Great experiment! I'd love to hear from any commercial solar installers in the comments. My gut feeling is that you were very generous on the costs. I wouldn't be surprised if that sort of system costs double when installed by professionals.
Absolutely, I was as generous as I could be and it was still a fortune! And I assumed you'd do all the work yourself. I reckon double for the full professional install is about right too.
The bulk of the cost there was storing energy for heat for 3 days. You could do that by adding thermal mass to your house, or some other form of heat store, which should be cheaper than batteries. And anyone who has a spare field for those panels would probably have room for a wind generator. However, I realise that the question you were trying to answer was whether a system like yours could do it, and applaud you for actually doing the numbers!
Great point Robin! Having a passivehaus would certainly reduce the heat load needed and may affect the calcs meaningfully. Tim is it possible to do a calculation based on a passivehaus?
@@bloodynorahvan2203 yes, of course, it'd just require a change to the demand values over the winter. I won't be doing that on a video though, I'll leave that as an exercise for interested viewers 😉
As someone who is off grid by necessity, the thing I noticed is that not a mention was made about changing behaviour. So many people are energy hogs and it is that that really needs to be addressed. In winter I go into economy mode as I know that my solar won’t cope and this, being on a boat, includes foraging for wood to burn, wearing a pullover, cooking efficiently, turning things off etc. It’s not a hardship, it’s a way of life and actually is quite satisfying to see just how little one can get away with. If I were on the grid then I would certainly have a hybrid system so that I can still be independent when the grid goes down and to get money for unused power and also to sell spare power from the batteries at peak times. On the boat I use spare summer generation for water heating and for charging my propulsion pack for the hybrid propulsion system giving free travel for 9 months of the year. Using these methods my total energy bill is around £25 per year which covers those prolonged periods of gloom, such as the recent fortnight, when I run my engine for maybe 30-40mins every so often to replenish what the solar has failed to.
Gosh yes these days it is sacrilegious to suggest not heating entire houses to a hot summer temperature it seems. I heat for free with scavenged wood too. But that does not mean I waste it! Not used any this season yet. When I do it is just to take the chill off not to turn it into the tropics. Dress properly for winter as you mention. Last year my neighbour was putting his bins out wearing t shirt shorts and flip flops mid winter. Explains a lot of the whinging about energy costs. I find the later you start using any heat the better the body adapts. Grew up with Jack Frost on the inside of windows. Vey pretty! Likewise I do not see it as any hardship. I could afford what I want but would not waste the money. Dehumidifiers and heated towel rails, not even my rich relatives have those. Getting a solar system soon and it will be interesting to see if it can cover my low usage in winter.
As we use gas to heat and cook our electric bill is fairly consistent and it’s the gas bill that fluctuates. I would love to have enough solar for our small amount of electricity used and to disconnect from the electric grid. That way we wouldn’t have to pay the excessive standing charge that covers all the green subsidies and ‘smart’ meter installations. However I doubt that would be allowed even though they’d have no problem cutting us off if we missed paying a bill :-)
@@X5493-c7p you can earn more from exporting excess solar in the summer than the cost of the standing charge. You'd have a negative bill if you stayed connected to the grid.
Going off grid, not as easy as it sounds! The first couple of weeks in November sum up quite nicely why it couldn't happen for me with now over 9kwp solar and 2 Powerwalls. I still had to import 220kwh in that timeframe! Key point in that sort of weather is doing the importing off peak
You could save some on the inverter. You only need a "January"-sized inverter. Making extra power in the summer is just a problem for your offgrid setup because it can't go anywhere. If your field was conveniently located next to a seaside resort, you could charge electric cars for 6 months.
I'm off grid and am always looking to lower my carbonfoot, I have solar, wind generation, would like to do hydropower for winter production so my research has lead me to a methane biogas distillery, which would power instant water boiler, cooker or generators to charge batterys for the winter. I do like the thought of the export tariffs on grid, where if you had a big enough solar array, you could have a very jolly Christmas.
Nice. Diversifying your energy supply is definitely the way to do this. If you've got a stream that you can hook up with a small hydro generator that'd be ideal.
@TimAndKatsGreenWalk Thanks. Methane distillery would be like the export solar, I would compress it during the summer and use it during the winter. Unfortunately I don't have a stream, but I do have a allot of what ifs aswell, and spent last winter researching many different whys of hydro power production, my favourite is the syphon, where the propeller would be at the top of the water holding the syphon would pull the water into the pipe creating a very strong vortex which would pass a very very shallow pitched propeller blade, so big among of torque large amount of power in a short time, but researching realistically the pellton wheel is the long term small stream producer.
Comparing my figures to yours, I have 7.56kWh split over E/W roof we are very very similar production. I have an ASHP with our radiators and again usage pretty similar to yours. However my home usage is quite high so in December last year I used 645kWh Day and 1105kWh Night. I roughly calculated 7 times the amount we have now to cover our use. I did look at adding an extra powerwall but the problem with extra battery is that for 5 months of the year it would help to reduce the day rate by moving more to the cheaper rate, but still we would need extra. Then it would be almost unused for 7 months. So very difficult to justify. I am now holding out for V2G as it makes far more sense to use my EV to help out in the winter to buy cheaper night rate and do it that way to save money.
Yeah, it's all about balance. I recently doubled our battery storage to 10 KWh as the price came down a lot, they removed VAT and we've got an EV so can charge for less overnight. But I don't expect it to do much for 3-4 months per year. Much as I'd love to have V2H or V2G neither my car or the charger support this so I'm definitely going to put that on the backburner for a while. We've kept out 7-seater petrol car for occasional long trips where we need the storage space but should hardly use it now. In 8-10 years when that gets replaced hopefully a decent second hand V2G car will be a reasonable price, we can fit a second charger and switch over.
Excellent and very thought provoking. Never thought it would ever be practical with our weather (or financially sensible), but theoretically you could well be able to reduce January's demand by approx. 50% - 600 kWh generation would be a much easier target! Possible ideas to achieve this could be : solar thermal panels for some of hot water demand / super insulate to passive house plus levels to all but reduce the heating demand / use MVHR so no need for dehumidifiers & also assists with heat demand.
Yes, a passivhaus would make it much easier, for sure, I agree. MVHR is also something I'm looking into but not for the purposes of making it easier to get off-grid! I still very much enjoy exporting my excess solar during the summer.
Good to watch. Having various scenarios mapped out gives a better understanding of things. Here in Central Europe, large ground mounted arrays are pretty common in people's back gardens (around the 10KWP size), to complement whatever they can get on the roof. Batteries are not so common yet, but it will happen.
I really wish we had a larger garden to install some ground mounted panels. Even a handful, say 5 or 6, would really help us out in the winter. Sadly we have no room for that.
Good morning Tim, I am Off-the-Grid in Estonia (I have a 2ha Organic Farm) and currently have 7,2kWp installed which produce already over 50kWh a day max. I assume, you have a horizontal geothermal system and what you can do is install two lops of roughly 1200m of PEX-A pipe in 2,5m and 1,5m depth and of course the loop for the HeatPump in 90cm depth. All you need is a Fronius Inverter with SmartMeter, the Ohm Pilot and an In-Flow Heater 9kW (per 13kWp you need one) and in the summer you heat up the ground to 70-80°C... ...and in the Winter you can even by-pass the HeatPump if you use an Underfloor Heating System as long, as the ground is above 40°C. Only if you have used up the heat between 70-40°C you will need the HeatPump, but with this high temperature the HeatPump will work MUCH lesser. I will start installing this system 2025 but put two GreenHouses on top of it, to reduce the energy loss and have the possibility to grow things in Winter time. I think, you do not need more than 26kWp of Solar panels and around 60kWh of usable Battery capacity. I use SOPzS Batteries with 70,5kWh and my Power Consumption is under 18kWh a day. Have a nice day
I have had similar thoughts regarding the storage of surplus solar kWh in the summer as heat to be used in winter. How are you going to insulate the heated soil to avoid too much heat loss? (I mean in addition to the green house)
Sand is an insulator... What you really need is volume and enough PEX-A pipe (is perfect suitable for it, but do not expose it at any costs to sun/UV) however, depending on your climat, one meter of Soil/on top of your HeatStorrage is enough. In a rainy environment, a drainage membrane is necessary.
11:15. 'An area like this...' but that's a LOT more than just 88 panels. The shortest row there is about 100 panels. My cousin has 118 of ye olde 200w (and an early FIT payout!) panels on top of a south facing barn in Devon and on Christmas day last year (grey and raining) I could charge my car at 7kW from her Zappi!
@TimAndKatsGreenWalk lots more than most people have but I think an off-grid system doesn't have to be 'off grid' - you can minimize your import (and maximize your export) for far less outlay and far fewer panels. 🤔
@@TimAndKatsGreenWalk I think a spreadsheet could be created that shows how little battery and solar you need to run without importing on perhaps all but the very worst days in winter and the returns from the solar and not buying anything in the summer....
I wonder if you could replace your dehumidifiers/cost with a Nuaire loft based air filter/heat exchanger (£300-400). Ours runs off auto settings mainly Winter/colder months, top of stairs covers whole house (4bed 2floors), ending any condensation we used to have, cost to run is negligible (can’t detect it, but guessing it’s £1 month or less). It has an internal heat ring which would cost more to run of course, but we don’t need/use this with ASHP. It’s so effective that my plan to create an external vent for kitchen is shelved as we simply get no condensation even on coldest days & heavy cooking! I did it originally for air quality as house seemed to well sealed, years ago when using gas boiler/rads. Best thing I did before installing solar/battery & ASHP.
That system sounds very interesting, could you provide a bit more info about it? What model do you have, how much did it cost to install, etc? Had a quick look and am guessing you have a Drimaster Eco Heat as this has the heater which you don't use. I don't think we'd use the heat either so the basic unit without it would probably be sufficient. Do you notice any difference in terms of air quality? Any sufferers of allergies or asthma in your house? Cheers.
@ hiya, I have been asthmatic in my past so sensitive to air quality. We’ve had this model about 4-5yrs, I fitted it physically but electrician connected as it’s a mains circuit. I have mine suspended by rope from loft roof to minimise noise/vibration, it’s essentially silent only slight air noise if you stand beneath it on landing in dead of night. Most visitors don’t know it’s there. We have a remote controller on wall, also controls on ceiling fitting. But auto factory settings for temperature, etc very good. Absolutely ended any condensation anywhere in house, air definitely better, fresher. Heat exchanger for outgoing stale air to incoming fresh seems quite efficient. Not impacted our ASHP in house. About £300 to purchase at time, electrician minimal as minutes to do, we had him doing other work as well.
With vehicle to grid, you could save the £27k battery cost, then if stuck, go out and rapid charge the car each day (assuming you don't let it get too low 😂) Great video!
Are any bidirectional V2G EV chargers on the market yet? There are plenty of cheap Nissan Leaf cars on the market that already facilitate V2G that would be far cheaper than buying house batteries.
Really interesting as usual. I’d be interested in the same calculation with an investment in Ripple - how much of a wind farm would you need to cover the winter low in solar
It would seem that the only way to go 'off-grid' in the UK for average Joe, is to go community solar/wind with a company like Octopus. Basically you could work out what you need to generate and then purchase sufficient generation from Octopus. They would then supply your house with all your electricity for the whole year without any of the dreaded daily charges. Octopus benefits because they are able to use the additional generation in the summer. This way you dont have to pay the high individual install costs, or the equipment and maintenance costs etcétera. There would of course be a maximum amount of Kw you could drawdown and if you went over, there would be a charge. It's also totally portable should you decide to move. Octopus would presumably install the sokar array / turbines close to your hone to save transmission costs.
Community scale solar installations is a great idea, and I think there might be one or two in existence already (I'd have to check though). I'm not sure how they currently work in terms of agreements with suppliers though.
@TimAndKatsGreenWalk I'm sure that I've seen a video with the CEO of Octopus talking about something like what I mean, and there are other schemes where the company will basically just "invest" in solar/wind on your behalf and pay dividends, but obviously it would be so much better to link it with your electric bill.
Ironically there is a TH-cam video of a house that has to go offgrid because the grid cost was £150k estimate. They did it with using a generator 10% of the time. But needed 88 panels and a giant battery system and 4 big victron inverters! Basically needed massive inverters to fill the batteries in 2 hours of sun on a winters day! TH-cam search victron to find it. Cost was about £55k. And panels had to be laid flat in field on ground to avoid planning permission!
Our energy provider offered us a Grid Connection for 28.000€ but our initial system (highly experimental) was 25.000€. We have several times reinvested (around 5600€) and will never pay again to a energy or grid provider. Argh, - with all these rising energy prices...
Thought provoking video! 👍 The mount structures would cost significantly more than all other elements bearing in mind you need to anchor them to the ground, concrete foundations etc to withstand storms (100 miles/hour or even higher). Adding a wind turbine to supplement generation at night will be beneficial. A tower structure, perhaps octagon in shape would very well accommodate all panels at optimum angle and work as the base for the wind turbine then you'd need a lot smaller land area and batteries. If there is a small steep hill next to your house, bingo
You can get some nifty ground mounting systems that use large metal screws that anchor into the ground, rather than needing concrete foundations. The advantage of those is that are much easier to remove afterwards too.
@@Jamey_ETHZurich_TUe_Rulez 88 panels each nearly 2m long, so you need very long south facing walls/fence/boundaries. My tower idea was to have structural integrity and uninterrupted solar generation all day
Yeah, you could definitely improve the payback by optimising for maximum generation in the summer instead, and so boost the summer generation at the expense of the winter. You'd be getting closer to £5-6k per year from export payments in that scenario.
The point about being off grid is that you learn to do more with less. It's a lifestyle more than it is about being independent from the grid. It's not really for those who enjoy a modern lifestyle with all the trimmings unless like you say, you have buckets of money. Heating and hot water are the real killers as off grid realistically you are going to need to burn something for that heat at the very least in winter.
That is true. In my thought experiment it was very much a case of keeping our existing lifestyle, but as you say in reality you'd have to make some pretty major changes. It could be feasible if you had a passivhause, for example, with very low heating demand.
Realistically the U.K. simply doesn’t have the climate where going off grid is viable. If you’re living somewhere where the climate has less seasonal variation, this month I’ve exported £3 so far, August for the same two weeks £40. My aim is probably similar to yours, go all electric and add a few more panels so that my annual cost is as close to zero, that does mean running up bills in winter, but it means getting into credit in summer
Would love to hear your thoughts on the installation of a wind turbine 300-500w output feeding a lithium battery or 2 at 12v through out the winter and connected to a 3000w inverter, winter is notorious for the wind speed increasing just as the solar decreases and no need for planning permission if in the garden of a detached property.
Domestic scale wind turbines are not great, really. They don't generate anywhere near as much as people assume and so the cost per kWh generated tends to be far worse than solar. They also need regular maintenance, which solar doesn't. Overall I'm not a fan (pun intended!)
Check your local restrictions on wind turbines, in our area we would need to mount them 24 feet above the top of our house. I love the ideas, but domestic wind turbines just don't work well, at present. You need quite a lot of wind to make them worthwhile.
fascinating stuff. makes me wonder how a wind/solar combo would work if you didn't happen to have a massive fictional field. Im also curious if there are any residential equivalents of an industrial electrolysis system, so summer excess energy becomes hydrogen, and in winter your stored hydrogen becomes electricity again..
Wind would definitely help in the winter, but you'd still need a large area to install sufficient turbines to generate enough. And I suspect it would be just as costly. I like the idea of a hydrogen factory though, that'd be fun!
Even though I knew the answer, I still found that interesting. I wouldn't want to go off grid, for the exact reasons you mention in the video. You can get away with a much smaller system and still effectively be bill free as you pointed out. Spare generation in the summer covers those poor winter months. This November is a perfect example of how bad it can get, my 15.5 kWp system is predicted to generate 13.4kWh a day, currently this month my average is just 7.7 kWh. PS Fogstar 15.5kWh battery is £2499 inc vat and delivery, that's £161 per kWh, they also have cheaper options 15.5 kWh for £1460, that's just £94 per kWh. Even though that saves some money you still need a suitable system to connect it all to the inverter or inverters, and that adds expense.
Hi Tim, an off topic question but in your office you have some really good storage solutions and in particular the white unit with 'oak' slimline drawers. Where did you get these drawers from as they seem to fit perfectly in the modules and as they look like the Ikea Kallax storage modules? Thanks in advance!
Ah, now those are Kat's cross stitch draws for holding all her threads and other items. Here's where she got them from: creations-by-rod.co.uk/ The white unit is indeed from Ikea, I forget the name of the unit, although you're probably right about them being Kallax.
If November's early output was anything to go by then it's no for me and that's with gas heating/cooking and minimal use when it's not sunny i.e. sod vacuuming etc - that's also with very little wind so a turbine wouldn't help that either...without a ginormous array (feasible) and equally large battery (probably unfeasible) it's just not practical without some form of instant back-up for the Dunkelflaute periods...
You would be fine going off grid for 9-10 month of the year in the U.K with a correctly configured EV and battery system. You may well need a low revolution petrol/ gas/ diesel generator for the wet dark months.
This is why XR has been pushing for a national retrofit programme. The bulk of the ~300 billion kWh of energy consumed in the UK’s homes annually is used for space and water heating. A substantial fraction (~ 2/3) of this consumption could be avoided with a national retrofit programme to the EnerPhit retrofit standard. Such a programme wouldn’t come cheap but it would be a one-off expenditure which could be paid for over several decades, either as an add-on to consumer energy bills, or, preferably, by a windfall tax on oil and gas companies.
Not cheap is a bit of an understatement for the cost of getting the UK housing stock up to Enerphit standard and maintaining it. Even if the workforce was available, I’m not sure there would be a net carbon advantage over getting the average EPC up to C, for example.
If there was a new magic battery-like storage that could take summer solar production peak energy and keep it till winter consumption peak then this might be more feasible. Or be closer to equator so there are less seasonal differences.
Yes, if you could store your summer generation for use in winter that'd be incredible. It'd require many 1000's of kWh of capacity though, in our case.
We can buy in USA 14kw wall mount battery $3300 indoors you pay slightly more about $200 for outdoor battery EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty
It's an interesting question posed. In practice, when people in the UK go off grid today they tend to use a generator for the coldest, darkest months. I think what sets your data apart is the inclusion of the heat pump and attempting to entirely generate from solar. Are there any other forms of electricity generation or energy storage that would compliment solar that could be deployed at a domestic scale? I think that's the real question to be answered. Great video btw
Biomass can be used, for example as ethanol in a generator, or wood in a Stirling engine. The latter option is commercially available in an off-grid ready package. Wind turbines can be an option in a location like a Scottish island. There's also hydrogen storage being offered commercially, a particularly expensive option at the moment I should add. For heat there is seasonal storage in soil, water, lime. For large commercial premises or small district heating networks, seasonal underground storage is commercially available and quite interesting. For individual houses, losses are a problem. The commercial systems I know for seasonal heat storage for individual houses do not cover the whole heating requirement. There's a solution in Germany ( marketed as Etank) where geothermal is combined with solar thermal. The soil is only insulated from the side and top and only 25 degrees Celsius are aimed for to keep losses down. They claim a seasonal COP for the heat pump of 8 or so, ie electricity is still required in January, just much less than with an air source heat pump.
Yes, indeed, the idea was to see if it was possible without any other energy source. The ideal would be a fast stream with a small turbine that could provide constant power. Although that's probably harder to come by than a suitably sized field!
I am no expert on this, but I would consider woodland to grow and coppice trees to make firewood. Ok, so you would need to either buy established woodland or have a lead time while the trees grow but once up and running there would be a carbon-neutral cycle happening. The trees would grow back quickly because with coppicing you keep the root system. You would need some way of making electricity for charging your chainsaw battery.
Use the excess solar in the summer to do the chopping. And a burner with back boiler would provide heat into water for a water tank which would have an emersion heater for use in summer when burner not in use.
If you have a sigenergy inverter and battery with the bidirectional DC charger module and a cupra born/Renault 5 which have V2H you could easily top up your batteries and not need as much solar panels for the poor generation months... Which makes it a lot more practical to be off Grid
@Jamey_ETHZurich_TUe_Rulez V2H will be the normal standard soon enough and an 80kwh car can run your house for days... Even if you're not filling up the house batteries... There are plenty of videos with the ford F150 lightning doing it.... It's a lot more practical than you think right now... Nevermind soon
@@TimAndKatsGreenWalk not necessarily you can DC fast charge your car and use the car as a house battery.. in the same way people were suggesting a diesel generator it would cost some money but not as much as 20 extra solar panels and it would probably be just for the very worst months
@@Jamey_ETHZurich_TUe_Rulez any car designed for V2H would be designed to cope with this and 10-15 years I'm pretty sure I'd have gone through at least 3 cars in that time... You're saying that we shouldn't use things that are actually specifically designed to do such things. Also it's to supplement the home to fill the gaps... Whilst there may be days it's not practical you can adjust your use and it's definitely possible and practical for the majority of the time.. definitely more practical than having a massive solar farm that you don't need for 9 months of the year and without the export money.... You could actually test it for a year before deciding to cut the cord
Nice intellectual exercise. Swings back towards a hybrid solution where you accept you'll be importing for (say) 3 months from mid Nov to mid Feb when you need to (at a cheap overnight rate). You could probably half the array or more. Keep playing with that spreadsheet (or get a bigger garden)😂
If you had an old mill with a nice reliable river then it’s probably just about possible. But as you say there are plenty of benefits from being on grid.
@@robinbennett5994 Although Kris was building that for someone else, he himself has a micro hydro generator, a wind turbine and solar panels, so I think he is pretty self sufficient in most weather. He does use a wood burner though for heat and hot water.
I have given this a lot of thought, the cheapest combination is a huge amount of panels, a large fraction of which are simply placed on the ground with a small spacer to get 5 cm ground clearance. The spacer can be a small wooden or plastic stick. Placed so close to the ground and without gaps, the panels will withstand a storm. You also do not need a large inverter. Panels can be connected in parallel. You can use a 12 kW hybrid inverter and connect about 48 kWp of panels and lose virtually no generation in December even on sunny days. On cloudy days horizontal panels actually produce slightly more power than tilted panels. The insolation is evenly spread across the sky, so panels that can see the whole sky, rather than just over half of it (70 degree tilt) can collect more sunlight. I have done comparisons with two systems next to each other. While the tilted system does much better on sunny days, on cloudy days, this is the other way round. When most days are cloudy, the difference in generation is not that large, but the horizontal orientation gives a much more even profile and therefore reduces the need for batteries. Even with a split of 15 kWp permanently installed to 60 kWp on the lawn for just the three darkest months there is a substantial surplus in the summer. You can put that into soil as heat using a concentric arrangement, where the edges are heated to about 50 degree with your heat pump and the extreme surplus days are used to heat a central space in the soil to well above 50 degrees Celsius. In winter you can thereby reduce your consumption for the heat pump substantially, for some days to zero. Total cost for 75 kWp, 60 only for the winter would be: 2000 pounds for a 20 kWp hybrid inverter, 5000 pounds for 45 kWh of battery storage, 6000 pounds for 75 kWp of panels, 2000 pounds for cables and miscellaneous parts, something like that, DIY about what your system cost and you'd be off grid and independent. As for export in summer: if everyone goes for cheap solar, the excess in summer is, without local seasonal storage, close to worthless. Sizing the grid to take your surplus solar in the summer to electrolysers for hydrogen production is a huge expense and the electrolysis units aren't free either.
You still need significantly more land than most people have access to, especially in the UK. That alone makes it unviable for the vast majority of people, irrespective of the cost (which is still a lot however you do it).
@@TimAndKatsGreenWalkThere are two perspectives I have on this. One is this question you are asking: would it be possible at vaguely acceptable cost just using solar and batteries, no fuel burnt and without any changes to behaviour. My answer to that is, yes, given a reasonably sized plot of land. I have got about 650 m2 and I think I could do it with the combination of extra panels just for winter and some very lossy seasonal heat storage. The other perspective is the following one: what kind of storage should we use as a country* to avoid excessive grid buildout costs? That's where I see a combination of batteries and heat storage. Particularly long duration heat storage underground is an area that deserves more attention. In urban environments this can be done with relatively shallow boreholes that are spaced tightly. This can be done virtually without losses, when mild, windy days are used for charging the soil heat battery with an air water heat pump and discharging on colder days within a few weeks with a water water heat pump. The big advantage of this is not just that surplus wind energy can be stored for cold days, you also reduce the required grid buildout, possibly even to such a degree that the present local grid will do. In the Netherlands this type of storage is already widely in use (about a hundred thousand flats), it's just not used to store wind energy, because price incentives are not there yet. In the Netherlands this type of system is used for seasonal storage with free heat in the summer obtained from offering cooling services.
@heikogerhauser3908 that's a very different video to the one I made. I was answering my specific question, I wasn't aiming to cover every option at every scale. There are other channels out there that cover that larger scale stuff much better than I could. Just Have a Think, for example ( www.youtube.com/@JustHaveaThink ).
Yes, a fun exercise. The cost of the field might be an issue and I believe the installation might easily be 10 x your estimate. Wire is very expensive these days. Connectivity and inverting would be done differently on that size of arrays. I think the method of payments might be different on such an industrial array. But a fun exercise anyway. Why are you using so much power on heating? Something seems to be wrong but I am sure it will be my understanding.
Rather off topic. I've had an ASHP for 14 years. I have no idea about its efficiency as there is no way to monitor or alter anything. The advice now is to run them in a steady state so that they don't cycle too much. My system is 12kw and has large radiators and underfloor heating and is way oversized for my 5 bed house. I am getting air to air installed as well. I think the efficiency should be a lot better than the current system, plus the cooling in Summer will be nice to have. I will still use the current system for hot water plus a little heating. Do you have any idea how to get the best efficiency out of air to air? Is it similar in that it should run for long periods to avoid cycling on and off?
Yes, pretty much the same applies, they're both heat pumps at the end of the day. I've been running ours low and slow (lowest fan setting) and it's been working well so far. I keep an eye on them though, and if I spot them cycling I'll turn them off for an hour or two, then back on once the house has cooled slightly. Our heat pumps are over-specced for our heat loss, so in mild weather they tend to start cycling if I leave them on for too long, so I'd recommend getting a heat loss survey or do your own calculation using Heat Punk, so that you don't run into the same problem (I'm intending to cover this is a future video, actually). Once it gets proper cold they'll probably stay on most of the day without cycling but we'll see how it goes.
Thanks Tim, The installer has recommended 2 fairly small outdoor units, each supplying 2 indoor units. The smaller units do seem to be more efficient. Like you, we are only going to have them in the most used rooms. I don't think they will be over spec for the room sizes and we can always use the ASHP to compliment them in very cold weather, if needed.
Do not buy anything except the best brands like Fujitsu and Toshiba. The Chinese brands are really inferior at heating although they are decent at cooling. Also if it doesn't bother you you can install floor indoor units which perform better at heating and worse at cooling.
I would buy 2 so you have nearly 30kw if your on grid charge at night for very cheap rate and use only battery during day EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty
The secret to off grid, is having the space for the solar. Not a crap ton of batteries. When you have 20-30kw of bifacial solar on the ground it does not matter if your system is only operating at 12% of its potential during the grey dismal months. Panels are cheap today when you buy them by the pallet.
@@TimAndKatsGreenWalk Most people who are "off grid" are on acreages. Not in a city. Where power is easily accessible. And like many people who are off grid today? It cost me less to be self sufficient than what the power company wanted to charge me to bring power 3/4 of a mile into this property.
And it's not that much space, about 4 m2 per kW. We've got 650 m2 of land, about half of which is lawn. That's 75 kWp of panels we could put there in the winter. As a trial I put 10 panels on the ground last winter and wired them two each in parallel to a Powerstation. Vastly overpaneling in winter time is no problem whatsoever. We also checked that the lawn didn't mind being covered by panels for approximately three months. One month after removing them the lawn where the panels had been could not be distinguished from the panel free bits of lawn. Panels are down to ridiculously low prices, PV Magazine just claimed 6 cents per Watt wholesale. That's about 50 pounds per kWp or less than 4000 pounds for 75 kWp.
Excess solar could be used to store ballons of hydrogen to run existing gas boiler. Your modeling graph would have to be reconfigured to factor that in. Good luck working out those stats
More realistic would be to buy a battery big enough to totally offset your daily consumption all year with cheap electric and see what the numbers say then. We are in the process of moving to this as part of a house renovation.
@TimAndKatsGreenWalk I did a quick calculation for myself last year and calculated that I'd need about 2000 kWh of batteries to get through the winter on excess solar generation from the summer months. Not realistic. Based on a similar situation to yours, with 10.5 kWhp PVs generating 8500 kWh per year and consumption at 9700 kWh per year. This includes charging my EV. Maybe I could lower consumption slightly by installing a Mixergy or ASHP water tank, instead of instant heated water, but I don't think that would make a big difference.
@@FoxInClogsyou wouldn’t need to store all 2000kwh at once though? I suspect most people would use less than 50kwh a day so having a battery of that size and charging with combination of cheap rate electric and solar.
Should the calculation take into account if you can get three phase Power? Scottish and Southern electricity networks have advised us we can have 11kw total PV Which i believe is sufficient for 1 tesla 2 battery (Output 5kw) and 14 (south facing) Solar panels (approximately 6 kw) total 11kw (we currently have 1 tesla 2 battery at 12 solar panels (430W each)) - so we are looking to add two additional south facing panels I was also looking to add an additional 9 North facing panels in order to try to get to net zero (electricity bill over 12 months) My solar provider has advised if i wanted to expand this one way would be to move to 3 phase supply this would allow me to treble what is allowed (e.g. to 33kw) Apparently introduction of three phase power could be £2k if it was close by or £20k if it was at the end of the road (looking to find this out currently) Obviously wouldn't proceed if it was a £20k cost
Well, the point of the video was to see if being off-grid was feasible, so no phases connected to the grid at all! If you're on-grid then three phases opens up so many options, I'd love to upgrade one day. But definitely staying on-grid!
@@TimAndKatsGreenWalk Have to say I am really enjoying using you excel spreadsheets One other approach might be to calculate KW requirements for 12 months of the whole system and then to expand the PV system so over 12 months the total cost is net zero (including what you can sell back to the grid). You may have done this already. Last year (prior to solar panels and battery) my KW usage was 8500 KW (but we have AC units) this year it is down to 6500kw In my case looking to add 2 further south facing panels and 9 north facing panels to generate 6500 kw or more. However now pushing up to the 11KW limited (specified by Southern Electric) hence my question on three phase supply. Has your electricity supplier limited you to a maximum wattage?
@@TimHolland-j8j our current limit is 5 kW but the DNO said off the record that I could probably go to to 7 without any problems. I would do that if I ever go ahead with my plans to get more panels on my North roof.
@@TimHolland-j8j I have a single phase power supply, and an export limit of 11.68kW. Consists of a 3.68kW inverter and an 8kW inverter. I now have 15.5kWp of panels, adding more panels doesn't require an increase in the export limit, it's the sum of the inverters that matter. I am gas and electric negative, looking like two years in a row now, and I didn't have as much PV last year.
@@TheRonskiman My solar installer advises that I am at 10kw already because of (1) 5kw solar inverter and (2) 5Kw tesla inverter. they have contacted SSE to see if the 11Kw limit can be increased
I think your battery and panel figures are wildly optimistic. Most home batteries come in at about £500 per kWh - not sure about UK but £50 for a 450W panel seems extraordinarily cheap. Plus you'd have to add in another £10K for wiring, breakers, safety equipment etc. I'm not sure where you're getting a 40kW hybrid inverter for £3K either? Remember the inverter has to be able to charge the batteries and be off grid.
Oh yes, absolutely, I was trying to be as generous as possible and it still came out extortionate. I got a lot of these values from Midsummer wholesale, there are actually 40+ kW commercial inverters for less than £3k, amazingly. Although those are not hybrids, as you point out.
Then pick the company with the cheapest standing charge and island yourself over the winter But still paying. It would be a small price to pay for missing out on the summer export
We earn almost enough from export in the summer to cover our winter costs with our existing system, and with only a few more panels we'd have a net zero bill. I'm satisfied with that.
Biggest problem is finding land that doesn't shade your ground mounted array where sun coming in at 15 degrees angle isn't shaded! It's not the land the panels take up. It's the 10-20 metres in front to be sure no house or trees shade the panels. You'd need a field or be on a hill!
If space was an issue and the cost of panels is getting pretty low wouldn't it make sense to have more of them, far closer to each other and only a small tilt towards the sun? Instead of a single 450w panel you could effectively have 3.5 panels and surely they wouldn't be less than a third as efficient just because they were flat or almost flat? While there's some big numbers in terms of cost here surely the biggest hurdle is having a small field available to deploy them?! In my situation I wanted as many panels as they could squeeze on my roof. My installer stated I couldn't go over 8.9 KWp because the DNO wouldn't allow it although I'm not sure how accurate that is. So we ended up with 23 390w panels when I think we could have got another 11 panels on my roof (we've got a big roof). However it's probably a moot point and 8.9 KWp was probably about right because the largest inverter Huawei do is 6 KWh and we do get a fair amount of clipping. Maybe we could pay for a second inverter? But either way there's zero chance of wanting to go off-grid in order to save ~£130 in standing charges. What I took from this video is more about scaling up the system and one day I'll look into it in the hope that I am allowed to by the DNO and it makes economic sense to do so.
The issue is the height of the sun in the sky, really. You'd get the same power out of flat panels covering the whole area of the ground as you would with fewer tilted panels aligned in such a way as to not cast shadows on the other panels. In both cases the sun is providing the same amount of power over the same area, as long as the panels capture it all. So in that case it'd be cheaper to have fewer panels that are tilted in the optimum way.
Tim, I have a question/idea for a future video. Do it and I promise I'll buy you a coffee.... A friend of mine recently mentioned that he thought his Ohme charger was going to receive a software update to allow bidirectional charging. This sounded a bit nuts to me because I presumed that to do this would need a change in hardware or possible also the cable. Seemed a bit too good to be true to basically get it for free through an update. So is it true? If it is then are other charger brands likely to get it? Is it then feasible that cars could be updated to allow it as well? I'm aware that some cars (BYD) are advertised as being ready for V2H/V2G but again I presumed this was because of some hardware included during manufacture. I'd realistically put this whole thing on the back burner until we replace our other car which won't be for a pretty long time. But be interesting to know if it could be closer than I thought.
I think you're right. The Ohme (and all other home 'chargers') are just a fancy mains supply. The charger is in the car, and the car's inverter is designed for driving the motor, not back-feeding the grid. V2G normally uses a grid-tied inverter in the 'charger' unit, which (as you say) is a significant piece of hardware. Cars could potentially be designed to use their own inverter for V2G, but none are at the moment.
I think this is possible - I was chatting to a tech guy at the Octopus stand at Everything Electric last month and he said they were working on much the same. I pushed him a bit on this and he effectively said 'Wait and see'. I wondered if he was joking but the idea that some chargers might get an upgrade to do this, would seem to support the idea.
I very much doubt a software update would make a normal EV charger bi-directional, I find that claim highly suspicious! But I'm not an expert so I will make some enquiries.
I have in addition to my 1,86kWp, 3,64kWp and 1,82kWp two Windmills 2000W and one with 700W. And with 70,5kWh batteries I just failed a little bit in December... NOT NICE! Comming year I get 24 panels 455Wp more, and this should do it in DECEMBER.
Interesting video, makes one think in regards to why aren’t electric companies offering free solar and batteries for households, generating electricity for the grid through households would be cost effective compared with wind turbines, don’t know how much a wind turbine cost not only the actual cost of the item but the running cost with maintenance and doesn’t generate anything when no baked beans or when the wind doesn’t blow , would make a good chart = wind turbine cost let’s say over year by year cost and how many homes with solar and batteries in comparison, as example one turbine cost could be a thousand homes with solar and battery, how much would the grid gain compared which each other , if you look at your house as an example so you’ve got a cost of many things for the chart 14 thousand outlay and how much excess you put back to the grid = times that by the cost of one turbine = how many homes one could get done , I think you would be surprised it might be much more cost effective for the electricity companies or not , can’t think if anyone has even looked at this scenario.
In some respects the good export tariffs nowadays are achieving more or less what you're suggesting, by paying people for their excess. It would be interesting to compare typical wind turbine costs to an equivalent amount of domestic solar though, I agree.
@@TimAndKatsGreenWalk You have the knowledge and capability to do such a chart , actually the more I think of it the more I think nobody has even looked into this , especially when you think the buying power of the electric companies therefore the cost would be a lot less with a big order compared to us just buying an individual unit for one house , if you take your situation at a cost of 14 thousand for one house can you imagine if you put an order in for a thousand items wouldn’t be surprised if it ended up being half that amount , sorry just had another crazy thought = if a thousand households were to buy solar and batteries for their individual homes but purchased them as a group at the same time it also could be half price , can you imagine give an order into a company for 1.4 million for a thousand kits the discount would be enormous, you know people in the industry would be curious to ask them what discount would you get if you put an order in for a thousand units like you have in your house , whoops that’s another chart pending = look at the benefits = keeps you out of mischief.
@@KavanOBrien looking back, companies offered free electricity for putting solar on the roof of consumers. The solar panels look to often be passed to the house owner at the end of the contract? For negative experiences of large solar buying companies, have a look at Spirit Energy's video on Solar Together London?
Interesting thought experiment - shows why solar alone will never be a solution for grid decarbonisation. With us all slowly moving to heat pumps electrical usage in winter will dwarf that of summer when solar production will eventually more than meet demands
Luckily we have a lot of wind generation in the UK. And an increasing amount of grid scale battery storage. It requires being on-grid to benefit from it though!
I'd say no, because you'll get cloudy days on end that will drain your batteries, and not be able to generate enough to recharge each day. Today we've generated 3.1 kWh from a 10.5kWp array, while using 11.3 kWh, and have not run the stove, washer or dryer.
How did you get the 11,3kWh? I have also Heating circulation pumps running 24/7 and also a 320l freezer box, a 80l Freezer and a 250l Fridge but I am under 5kWh (and yes, I switch off my two Laptops and my Workstation)
@@michellekonzack Can't give an exact breakdown, but we have about 300W constantly from 2 freezers and a fridge freezer, computers, lights etc. Later in the day we also charged our EV, and as that's currently from a 120V external wall socket that adds into the mix, but asn't in this number. Any use the microwave or air fryer also adds in. Our solar feeds only "essential loads", i.e. those that we would wish to maintain during a powercut, so it excludes the stove, washer and dryer, and will also exclude a 240V 50A socket we will get for the EV level 2 charger. Late September we did have a couple of days around 5-6 kWh, but most days we top 10 kWh. Household of four.
Before I even started watching this I thought it would be unrealistic to be able to go off grid from solar alone. You need loads of space and loads of money and most people done have enough of either. Good video though
@@TimAndKatsGreenWalk Without watching the video as I'm at work, I can also say the answer is no. We have a 50kWp array here at work, and I've seen some very low days. If you can install the same along with a massive battery and your usage is low, then it's possible. Best bet have a piece of land with a decent stream with a good upstream head, you can then generate 1 kW or more 24/7 pretty easily. Add some PV for the summer months if water flow reduces.
Looks like 40 ish% efficiency is just about doable with perovskite-silicone composite panels. Those might be just around the corner for domestic customers (around the corner being a few more years at least, I suspect).
@ It will depend on your power usage as well as location. We have two EVs and without resorting to public charging it would be impossible to run those off grid 365 days a year without a grid connection. Yes I could get rid of the EVs but the savings I make from not buying petrol or diesel each week pay for my entire grid energy cost, both gas and electricity.
In spring I start rebuilding a russian UAZ 3303 into a 48V EV with a Victron Multiplus-II 48/10000 and ~62kWh of LiFePO4 Batteries. In the summer I will NEVER need a public charging station, but in the winter I charge on a public charging station and can even save the money for a noisy generator at home if necessary...
Bit weird not doing it for 'your array'. Let alone making up a ground mounted rare array type. All very well saying a perfect set up up and plenty of land to spare you 'could'. Plus too much wittering on about the costs, which are irrelevant, the point was 'can' you go off grid in the UK! There also is the option of some other form of winter heating. Even a generator to pick up the mid winter slack. More usage reduction needed! My electricity bill estimates about 2000kwh a year. No gas available.
@@TimAndKatsGreenWalk anything is possible, but at what cost! - you'll see this daily from the political hierarchy in their 4x4's / oil driven houses. Do as we say not as we do?
Your video reminded me of this video from a couple that IS off grid (in north Idaho) and uses a generator in December, but STILL gets more than half their electricity from solar…. th-cam.com/video/fv68DWKQ9zA/w-d-xo.html
Great experiment!
I'd love to hear from any commercial solar installers in the comments.
My gut feeling is that you were very generous on the costs.
I wouldn't be surprised if that sort of system costs double when installed by professionals.
Absolutely, I was as generous as I could be and it was still a fortune! And I assumed you'd do all the work yourself. I reckon double for the full professional install is about right too.
The bulk of the cost there was storing energy for heat for 3 days. You could do that by adding thermal mass to your house, or some other form of heat store, which should be cheaper than batteries.
And anyone who has a spare field for those panels would probably have room for a wind generator.
However, I realise that the question you were trying to answer was whether a system like yours could do it, and applaud you for actually doing the numbers!
It's always worth doing the numbers!
Great point Robin! Having a passivehaus would certainly reduce the heat load needed and may affect the calcs meaningfully. Tim is it possible to do a calculation based on a passivehaus?
@@bloodynorahvan2203 yes, of course, it'd just require a change to the demand values over the winter. I won't be doing that on a video though, I'll leave that as an exercise for interested viewers 😉
As someone who is off grid by necessity, the thing I noticed is that not a mention was made about changing behaviour. So many people are energy hogs and it is that that really needs to be addressed. In winter I go into economy mode as I know that my solar won’t cope and this, being on a boat, includes foraging for wood to burn, wearing a pullover, cooking efficiently, turning things off etc. It’s not a hardship, it’s a way of life and actually is quite satisfying to see just how little one can get away with. If I were on the grid then I would certainly have a hybrid system so that I can still be independent when the grid goes down and to get money for unused power and also to sell spare power from the batteries at peak times. On the boat I use spare summer generation for water heating and for charging my propulsion pack for the hybrid propulsion system giving free travel for 9 months of the year. Using these methods my total energy bill is around £25 per year which covers those prolonged periods of gloom, such as the recent fortnight, when I run my engine for maybe 30-40mins every so often to replenish what the solar has failed to.
Yes, the point of the video was to demonstrate how much would be needed to maintain our current lifestyle.
Gosh yes these days it is sacrilegious to suggest not heating entire houses to a hot summer temperature it seems. I heat for free with scavenged wood too. But that does not mean I waste it! Not used any this season yet. When I do it is just to take the chill off not to turn it into the tropics. Dress properly for winter as you mention. Last year my neighbour was putting his bins out wearing t shirt shorts and flip flops mid winter. Explains a lot of the whinging about energy costs. I find the later you start using any heat the better the body adapts. Grew up with Jack Frost on the inside of windows. Vey pretty! Likewise I do not see it as any hardship. I could afford what I want but would not waste the money.
Dehumidifiers and heated towel rails, not even my rich relatives have those.
Getting a solar system soon and it will be interesting to see if it can cover my low usage in winter.
As we use gas to heat and cook our electric bill is fairly consistent and it’s the gas bill that fluctuates. I would love to have enough solar for our small amount of electricity used and to disconnect from the electric grid. That way we wouldn’t have to pay the excessive standing charge that covers all the green subsidies and ‘smart’ meter installations. However I doubt that would be allowed even though they’d have no problem cutting us off if we missed paying a bill :-)
@@X5493-c7p you can earn more from exporting excess solar in the summer than the cost of the standing charge. You'd have a negative bill if you stayed connected to the grid.
Hey Tim, Looking at my panels, all covered in snow and 0 kWh produced today, I'm glad of my grid connection!
Howdy Dave. Yes indeed, some days you just know you're gonna need the grid!
Fantastic Tim. I love a good spreadsheet! Well done.
Thank you! You can never have too many spreadsheets.
Going off grid, not as easy as it sounds! The first couple of weeks in November sum up quite nicely why it couldn't happen for me with now over 9kwp solar and 2 Powerwalls. I still had to import 220kwh in that timeframe! Key point in that sort of weather is doing the importing off peak
Yup, exactly!
You could save some on the inverter. You only need a "January"-sized inverter. Making extra power in the summer is just a problem for your offgrid setup because it can't go anywhere. If your field was conveniently located next to a seaside resort, you could charge electric cars for 6 months.
Yes, that might work. I like the idea of summer charging, that'd be a nice earner if you were in the right spot.
I'm off grid and am always looking to lower my carbonfoot, I have solar, wind generation, would like to do hydropower for winter production so my research has lead me to a methane biogas distillery, which would power instant water boiler, cooker or generators to charge batterys for the winter.
I do like the thought of the export tariffs on grid, where if you had a big enough solar array, you could have a very jolly Christmas.
Nice. Diversifying your energy supply is definitely the way to do this. If you've got a stream that you can hook up with a small hydro generator that'd be ideal.
@TimAndKatsGreenWalk Thanks. Methane distillery would be like the export solar, I would compress it during the summer and use it during the winter.
Unfortunately I don't have a stream, but I do have a allot of what ifs aswell, and spent last winter researching many different whys of hydro power production, my favourite is the syphon, where the propeller would be at the top of the water holding the syphon would pull the water into the pipe creating a very strong vortex which would pass a very very shallow pitched propeller blade, so big among of torque large amount of power in a short time, but researching realistically the pellton wheel is the long term small stream producer.
Comparing my figures to yours, I have 7.56kWh split over E/W roof we are very very similar production. I have an ASHP with our radiators and again usage pretty similar to yours. However my home usage is quite high so in December last year I used 645kWh Day and 1105kWh Night. I roughly calculated 7 times the amount we have now to cover our use.
I did look at adding an extra powerwall but the problem with extra battery is that for 5 months of the year it would help to reduce the day rate by moving more to the cheaper rate, but still we would need extra. Then it would be almost unused for 7 months. So very difficult to justify.
I am now holding out for V2G as it makes far more sense to use my EV to help out in the winter to buy cheaper night rate and do it that way to save money.
Yeah, it's all about balance. I recently doubled our battery storage to 10 KWh as the price came down a lot, they removed VAT and we've got an EV so can charge for less overnight. But I don't expect it to do much for 3-4 months per year. Much as I'd love to have V2H or V2G neither my car or the charger support this so I'm definitely going to put that on the backburner for a while. We've kept out 7-seater petrol car for occasional long trips where we need the storage space but should hardly use it now. In 8-10 years when that gets replaced hopefully a decent second hand V2G car will be a reasonable price, we can fit a second charger and switch over.
V2G really would be a game changer. I hope it hurries up and becomes more widespread soon.
Evman was sceptical in a recent video.
Excellent and very thought provoking. Never thought it would ever be practical with our weather (or financially sensible), but
theoretically you could well be able to reduce January's demand by approx. 50% - 600 kWh generation would be a much easier target!
Possible ideas to achieve this could be : solar thermal panels for some of hot water demand / super insulate to passive house plus levels to all but reduce the heating demand / use MVHR so no need for dehumidifiers & also assists with heat demand.
Yes, a passivhaus would make it much easier, for sure, I agree. MVHR is also something I'm looking into but not for the purposes of making it easier to get off-grid! I still very much enjoy exporting my excess solar during the summer.
Good to watch. Having various scenarios mapped out gives a better understanding of things. Here in Central Europe, large ground mounted arrays are pretty common in people's back gardens (around the 10KWP size), to complement whatever they can get on the roof. Batteries are not so common yet, but it will happen.
I really wish we had a larger garden to install some ground mounted panels. Even a handful, say 5 or 6, would really help us out in the winter. Sadly we have no room for that.
Good morning Tim,
I am Off-the-Grid in Estonia (I have a 2ha Organic Farm) and currently have 7,2kWp installed which produce already over 50kWh a day max.
I assume, you have a horizontal geothermal system and what you can do is install two lops of roughly 1200m of PEX-A pipe in 2,5m and 1,5m depth and of course the loop for the HeatPump in 90cm depth.
All you need is a Fronius Inverter with SmartMeter, the Ohm Pilot and an In-Flow Heater 9kW (per 13kWp you need one) and in the summer you heat up the ground to 70-80°C...
...and in the Winter you can even by-pass the HeatPump if you use an Underfloor Heating System as long, as the ground is above 40°C.
Only if you have used up the heat between 70-40°C you will need the HeatPump, but with this high temperature the HeatPump will work MUCH lesser.
I will start installing this system 2025 but put two GreenHouses on top of it, to reduce the energy loss and have the possibility to grow things in Winter time.
I think, you do not need more than 26kWp of Solar panels and around 60kWh of usable Battery capacity. I use SOPzS Batteries with 70,5kWh and my Power Consumption is under 18kWh a day.
Have a nice day
That sounds like a neat system. Sadly we don't have anywhere near enough land to do something like that.
Too bad....
I have had similar thoughts regarding the storage of surplus solar kWh in the summer as heat to be used in winter. How are you going to insulate the heated soil to avoid too much heat loss? (I mean in addition to the green house)
Sand is an insulator...
What you really need is volume and enough PEX-A pipe (is perfect suitable for it, but do not expose it at any costs to sun/UV)
however, depending on your climat, one meter of Soil/on top of your HeatStorrage is enough. In a rainy environment, a drainage membrane is necessary.
11:15. 'An area like this...' but that's a LOT more than just 88 panels. The shortest row there is about 100 panels.
My cousin has 118 of ye olde 200w (and an early FIT payout!) panels on top of a south facing barn in Devon and on Christmas day last year (grey and raining) I could charge my car at 7kW from her Zappi!
Well, I showed the area required was more than 600m^2, so 25m x 25m, which is considerably bigger than what most people have access to.
@TimAndKatsGreenWalk lots more than most people have but I think an off-grid system doesn't have to be 'off grid' - you can minimize your import (and maximize your export) for far less outlay and far fewer panels. 🤔
@@FFVoyager yes, exactly, there's no good reason to be totally off grid, really.
@@TimAndKatsGreenWalk I think a spreadsheet could be created that shows how little battery and solar you need to run without importing on perhaps all but the very worst days in winter and the returns from the solar and not buying anything in the summer....
I wonder if you could replace your dehumidifiers/cost with a Nuaire loft based air filter/heat exchanger (£300-400). Ours runs off auto settings mainly Winter/colder months, top of stairs covers whole house (4bed 2floors), ending any condensation we used to have, cost to run is negligible (can’t detect it, but guessing it’s £1 month or less). It has an internal heat ring which would cost more to run of course, but we don’t need/use this with ASHP. It’s so effective that my plan to create an external vent for kitchen is shelved as we simply get no condensation even on coldest days & heavy cooking! I did it originally for air quality as house seemed to well sealed, years ago when using gas boiler/rads. Best thing I did before installing solar/battery & ASHP.
That system sounds very interesting, could you provide a bit more info about it? What model do you have, how much did it cost to install, etc? Had a quick look and am guessing you have a Drimaster Eco Heat as this has the heater which you don't use. I don't think we'd use the heat either so the basic unit without it would probably be sufficient. Do you notice any difference in terms of air quality? Any sufferers of allergies or asthma in your house? Cheers.
Yes, that is the sort of thing I'm investigating, as it happens (not that exact model but I'm going to look into that, thanks for mentioning it).
@ i think the company Nuaire is based in Wales. They’re online.
@ hiya, I have been asthmatic in my past so sensitive to air quality. We’ve had this model about 4-5yrs, I fitted it physically but electrician connected as it’s a mains circuit. I have mine suspended by rope from loft roof to minimise noise/vibration, it’s essentially silent only slight air noise if you stand beneath it on landing in dead of night. Most visitors don’t know it’s there. We have a remote controller on wall, also controls on ceiling fitting. But auto factory settings for temperature, etc very good. Absolutely ended any condensation anywhere in house, air definitely better, fresher. Heat exchanger for outgoing stale air to incoming fresh seems quite efficient. Not impacted our ASHP in house. About £300 to purchase at time, electrician minimal as minutes to do, we had him doing other work as well.
With vehicle to grid, you could save the £27k battery cost, then if stuck, go out and rapid charge the car each day (assuming you don't let it get too low 😂) Great video!
Are any bidirectional V2G EV chargers on the market yet? There are plenty of cheap Nissan Leaf cars on the market that already facilitate V2G that would be far cheaper than buying house batteries.
I really hope V2G hurries up and goes mainstream soon, that'd be amazing.
Loved the silly nonsense, Tim. 😊
Glad to hear it!
Really interesting as usual. I’d be interested in the same calculation with an investment in Ripple - how much of a wind farm would you need to cover the winter low in solar
Good question. It'd be quite a bit in order to cover the heating load.
It would seem that the only way to go 'off-grid' in the UK for average Joe, is to go community solar/wind with a company like Octopus.
Basically you could work out what you need to generate and then purchase sufficient generation from Octopus. They would then supply your house with all your electricity for the whole year without any of the dreaded daily charges. Octopus benefits because they are able to use the additional generation in the summer. This way you dont have to pay the high individual install costs, or the equipment and maintenance costs etcétera.
There would of course be a maximum amount of Kw you could drawdown and if you went over, there would be a charge. It's also totally portable should you decide to move.
Octopus would presumably install the sokar array / turbines close to your hone to save transmission costs.
Community scale solar installations is a great idea, and I think there might be one or two in existence already (I'd have to check though). I'm not sure how they currently work in terms of agreements with suppliers though.
@TimAndKatsGreenWalk I'm sure that I've seen a video with the CEO of Octopus talking about something like what I mean, and there are other schemes where the company will basically just "invest" in solar/wind on your behalf and pay dividends, but obviously it would be so much better to link it with your electric bill.
That was fun! And I’m sort of relieved the payback was ten years - any faster and I’d be out looking for a field..
Man, I'd love a field where I could install a ground mounted system. I'd still want it to be grid-tied though!
Ironically there is a TH-cam video of a house that has to go offgrid because the grid cost was £150k estimate. They did it with using a generator 10% of the time. But needed 88 panels and a giant battery system and 4 big victron inverters! Basically needed massive inverters to fill the batteries in 2 hours of sun on a winters day! TH-cam search victron to find it. Cost was about £55k. And panels had to be laid flat in field on ground to avoid planning permission!
Well, there you go, seems I wasn't a million miles off.
Our energy provider offered us a Grid Connection for 28.000€ but our initial system (highly experimental) was 25.000€.
We have several times reinvested (around 5600€) and will never pay again to a energy or grid provider.
Argh, - with all these rising energy prices...
Thought provoking video! 👍
The mount structures would cost significantly more than all other elements bearing in mind you need to anchor them to the ground, concrete foundations etc to withstand storms (100 miles/hour or even higher). Adding a wind turbine to supplement generation at night will be beneficial. A tower structure, perhaps octagon in shape would very well accommodate all panels at optimum angle and work as the base for the wind turbine then you'd need a lot smaller land area and batteries. If there is a small steep hill next to your house, bingo
You can get some nifty ground mounting systems that use large metal screws that anchor into the ground, rather than needing concrete foundations. The advantage of those is that are much easier to remove afterwards too.
@@Jamey_ETHZurich_TUe_Rulez 88 panels each nearly 2m long, so you need very long south facing walls/fence/boundaries. My tower idea was to have structural integrity and uninterrupted solar generation all day
@@TimAndKatsGreenWalk Thanks for that Tim, I looked at some of those, they're indeed versatile 👍
Soooo, I’m going to be forced to go off grid in Derbyshire from January.
I’d be interested on your take on it.
I put my take into this video! You're gonna need more than just solar panels and batteries, basically.
Very interesting! Can you optimise this size of the installation for the best payback assuming you remain on the grid?
Yeah, you could definitely improve the payback by optimising for maximum generation in the summer instead, and so boost the summer generation at the expense of the winter. You'd be getting closer to £5-6k per year from export payments in that scenario.
The point about being off grid is that you learn to do more with less. It's a lifestyle more than it is about being independent from the grid. It's not really for those who enjoy a modern lifestyle with all the trimmings unless like you say, you have buckets of money.
Heating and hot water are the real killers as off grid realistically you are going to need to burn something for that heat at the very least in winter.
That is true. In my thought experiment it was very much a case of keeping our existing lifestyle, but as you say in reality you'd have to make some pretty major changes. It could be feasible if you had a passivhause, for example, with very low heating demand.
Realistically the U.K. simply doesn’t have the climate where going off grid is viable. If you’re living somewhere where the climate has less seasonal variation, this month I’ve exported £3 so far, August for the same two weeks £40.
My aim is probably similar to yours, go all electric and add a few more panels so that my annual cost is as close to zero, that does mean running up bills in winter, but it means getting into credit in summer
Yes, exactly. It wouldn't take much more generation for us to have a net zero annual bill, so I'm hoping to achieve that one day.
This will work until the duck curve gets to the point where the power companies will no longer pay us for export in the height of summer
Would love to hear your thoughts on the installation of a wind turbine 300-500w output feeding a lithium battery or 2 at 12v through out the winter and connected to a 3000w inverter, winter is notorious for the wind speed increasing just as the solar decreases and no need for planning permission if in the garden of a detached property.
Domestic scale wind turbines are not great, really. They don't generate anywhere near as much as people assume and so the cost per kWh generated tends to be far worse than solar. They also need regular maintenance, which solar doesn't. Overall I'm not a fan (pun intended!)
This is a good summary, too: th-cam.com/video/HW4iyMnblZ8/w-d-xo.html
Check your local restrictions on wind turbines, in our area we would need to mount them 24 feet above the top of our house.
I love the ideas, but domestic wind turbines just don't work well, at present. You need quite a lot of wind to make them worthwhile.
fascinating stuff. makes me wonder how a wind/solar combo would work if you didn't happen to have a massive fictional field.
Im also curious if there are any residential equivalents of an industrial electrolysis system, so summer excess energy becomes hydrogen, and in winter your stored hydrogen becomes electricity again..
Wind would definitely help in the winter, but you'd still need a large area to install sufficient turbines to generate enough. And I suspect it would be just as costly. I like the idea of a hydrogen factory though, that'd be fun!
Even though I knew the answer, I still found that interesting. I wouldn't want to go off grid, for the exact reasons you mention in the video. You can get away with a much smaller system and still effectively be bill free as you pointed out. Spare generation in the summer covers those poor winter months. This November is a perfect example of how bad it can get, my 15.5 kWp system is predicted to generate 13.4kWh a day, currently this month my average is just 7.7 kWh. PS Fogstar 15.5kWh battery is £2499 inc vat and delivery, that's £161 per kWh, they also have cheaper options 15.5 kWh for £1460, that's just £94 per kWh. Even though that saves some money you still need a suitable system to connect it all to the inverter or inverters, and that adds expense.
Yup, however you do it it'll cost a fortune, and require a lot of land.
Hi Tim, an off topic question but in your office you have some really good storage solutions and in particular the white unit with 'oak' slimline drawers. Where did you get these drawers from as they seem to fit perfectly in the modules and as they look like the Ikea Kallax storage modules? Thanks in advance!
Ah, now those are Kat's cross stitch draws for holding all her threads and other items. Here's where she got them from: creations-by-rod.co.uk/
The white unit is indeed from Ikea, I forget the name of the unit, although you're probably right about them being Kallax.
@@TimAndKatsGreenWalk Thank you very helpful indeed!
If November's early output was anything to go by then it's no for me and that's with gas heating/cooking and minimal use when it's not sunny i.e. sod vacuuming etc - that's also with very little wind so a turbine wouldn't help that either...without a ginormous array (feasible) and equally large battery (probably unfeasible) it's just not practical without some form of instant back-up for the Dunkelflaute periods...
Yup, it's pretty much a non-starter for anyone who doesn't own a huge amount of land and has money to burn.
You would be fine going off grid for 9-10 month of the year in the U.K with a correctly configured EV and battery system. You may well need a low revolution petrol/ gas/ diesel generator for the wet dark months.
Indeed, it's those tricky winter months that get you.
This is why XR has been pushing for a national retrofit programme. The bulk of the ~300 billion kWh of energy consumed in the UK’s homes annually is used for space and water heating. A substantial fraction (~ 2/3) of this consumption could be avoided with a national retrofit programme to the EnerPhit retrofit standard. Such a programme wouldn’t come cheap but it would be a one-off expenditure which could be paid for over several decades, either as an add-on to consumer energy bills, or, preferably, by a windfall tax on oil and gas companies.
That would definitely help a lot. Our house is pretty well insulated but it's still a way off of the EnerPhit standard.
Not cheap is a bit of an understatement for the cost of getting the UK housing stock up to Enerphit standard and maintaining it. Even if the workforce was available, I’m not sure there would be a net carbon advantage over getting the average EPC up to C, for example.
If there was a new magic battery-like storage that could take summer solar production peak energy and keep it till winter consumption peak then this might be more feasible. Or be closer to equator so there are less seasonal differences.
Yes, if you could store your summer generation for use in winter that'd be incredible. It'd require many 1000's of kWh of capacity though, in our case.
@ yes - it’d probably cost more in batteries than the rest of the house!
We can buy in USA 14kw wall mount battery
$3300 indoors you pay slightly more about $200 for outdoor battery
EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty
Ok
It's an interesting question posed. In practice, when people in the UK go off grid today they tend to use a generator for the coldest, darkest months.
I think what sets your data apart is the inclusion of the heat pump and attempting to entirely generate from solar.
Are there any other forms of electricity generation or energy storage that would compliment solar that could be deployed at a domestic scale? I think that's the real question to be answered.
Great video btw
Biomass can be used, for example as ethanol in a generator, or wood in a Stirling engine. The latter option is commercially available in an off-grid ready package. Wind turbines can be an option in a location like a Scottish island. There's also hydrogen storage being offered commercially, a particularly expensive option at the moment I should add. For heat there is seasonal storage in soil, water, lime. For large commercial premises or small district heating networks, seasonal underground storage is commercially available and quite interesting. For individual houses, losses are a problem. The commercial systems I know for seasonal heat storage for individual houses do not cover the whole heating requirement. There's a solution in Germany ( marketed as Etank) where geothermal is combined with solar thermal. The soil is only insulated from the side and top and only 25 degrees Celsius are aimed for to keep losses down. They claim a seasonal COP for the heat pump of 8 or so, ie electricity is still required in January, just much less than with an air source heat pump.
Yes, indeed, the idea was to see if it was possible without any other energy source. The ideal would be a fast stream with a small turbine that could provide constant power. Although that's probably harder to come by than a suitably sized field!
I am no expert on this, but I would consider woodland to grow and coppice trees to make firewood. Ok, so you would need to either buy established woodland or have a lead time while the trees grow but once up and running there would be a carbon-neutral cycle happening. The trees would grow back quickly because with coppicing you keep the root system. You would need some way of making electricity for charging your chainsaw battery.
Use the excess solar in the summer to do the chopping. And a burner with back boiler would provide heat into water for a water tank which would have an emersion heater for use in summer when burner not in use.
This is fine when you are younger - but the effort involved when you get to retirement age might prove to be rather daunting.
It all comes down to land. You need a lot regardless of what route you take!
If you have a sigenergy inverter and battery with the bidirectional DC charger module and a cupra born/Renault 5 which have V2H you could easily top up your batteries and not need as much solar panels for the poor generation months... Which makes it a lot more practical to be off Grid
@Jamey_ETHZurich_TUe_Rulez V2H will be the normal standard soon enough and an 80kwh car can run your house for days... Even if you're not filling up the house batteries... There are plenty of videos with the ford F150 lightning doing it.... It's a lot more practical than you think right now... Nevermind soon
You still need enough generation to cover your consumption though.
@@TimAndKatsGreenWalk not necessarily you can DC fast charge your car and use the car as a house battery.. in the same way people were suggesting a diesel generator it would cost some money but not as much as 20 extra solar panels and it would probably be just for the very worst months
@@Jamey_ETHZurich_TUe_Rulez any car designed for V2H would be designed to cope with this and 10-15 years I'm pretty sure I'd have gone through at least 3 cars in that time... You're saying that we shouldn't use things that are actually specifically designed to do such things. Also it's to supplement the home to fill the gaps... Whilst there may be days it's not practical you can adjust your use and it's definitely possible and practical for the majority of the time.. definitely more practical than having a massive solar farm that you don't need for 9 months of the year and without the export money.... You could actually test it for a year before deciding to cut the cord
I have done it and on the cheap with Lead Acid batteries.
And a field of solar?
Nice intellectual exercise. Swings back towards a hybrid solution where you accept you'll be importing for (say) 3 months from mid Nov to mid Feb when you need to (at a cheap overnight rate). You could probably half the array or more. Keep playing with that spreadsheet (or get a bigger garden)😂
Indeed. I would love a big enough garden for a ground mounted system, that'd be awesome. But there's no way we're moving from here any time soon!
If you had an old mill with a nice reliable river then it’s probably just about possible. But as you say there are plenty of benefits from being on grid.
Ooh, that would be amazing.
Kris Harbour has several videos of building a water wheel like this - highly recommended. th-cam.com/video/PvgeSJKlNUs/w-d-xo.html
@@robinbennett5994 Although Kris was building that for someone else, he himself has a micro hydro generator, a wind turbine and solar panels, so I think he is pretty self sufficient in most weather. He does use a wood burner though for heat and hot water.
I have given this a lot of thought, the cheapest combination is a huge amount of panels, a large fraction of which are simply placed on the ground with a small spacer to get 5 cm ground clearance. The spacer can be a small wooden or plastic stick. Placed so close to the ground and without gaps, the panels will withstand a storm. You also do not need a large inverter. Panels can be connected in parallel. You can use a 12 kW hybrid inverter and connect about 48 kWp of panels and lose virtually no generation in December even on sunny days. On cloudy days horizontal panels actually produce slightly more power than tilted panels. The insolation is evenly spread across the sky, so panels that can see the whole sky, rather than just over half of it (70 degree tilt) can collect more sunlight. I have done comparisons with two systems next to each other. While the tilted system does much better on sunny days, on cloudy days, this is the other way round. When most days are cloudy, the difference in generation is not that large, but the horizontal orientation gives a much more even profile and therefore reduces the need for batteries. Even with a split of 15 kWp permanently installed to 60 kWp on the lawn for just the three darkest months there is a substantial surplus in the summer. You can put that into soil as heat using a concentric arrangement, where the edges are heated to about 50 degree with your heat pump and the extreme surplus days are used to heat a central space in the soil to well above 50 degrees Celsius. In winter you can thereby reduce your consumption for the heat pump substantially, for some days to zero. Total cost for 75 kWp, 60 only for the winter would be: 2000 pounds for a 20 kWp hybrid inverter, 5000 pounds for 45 kWh of battery storage, 6000 pounds for 75 kWp of panels, 2000 pounds for cables and miscellaneous parts, something like that, DIY about what your system cost and you'd be off grid and independent. As for export in summer: if everyone goes for cheap solar, the excess in summer is, without local seasonal storage, close to worthless. Sizing the grid to take your surplus solar in the summer to electrolysers for hydrogen production is a huge expense and the electrolysis units aren't free either.
You still need significantly more land than most people have access to, especially in the UK. That alone makes it unviable for the vast majority of people, irrespective of the cost (which is still a lot however you do it).
@@TimAndKatsGreenWalkThere are two perspectives I have on this. One is this question you are asking: would it be possible at vaguely acceptable cost just using solar and batteries, no fuel burnt and without any changes to behaviour. My answer to that is, yes, given a reasonably sized plot of land. I have got about 650 m2 and I think I could do it with the combination of extra panels just for winter and some very lossy seasonal heat storage. The other perspective is the following one: what kind of storage should we use as a country* to avoid excessive grid buildout costs? That's where I see a combination of batteries and heat storage. Particularly long duration heat storage underground is an area that deserves more attention. In urban environments this can be done with relatively shallow boreholes that are spaced tightly. This can be done virtually without losses, when mild, windy days are used for charging the soil heat battery with an air water heat pump and discharging on colder days within a few weeks with a water water heat pump. The big advantage of this is not just that surplus wind energy can be stored for cold days, you also reduce the required grid buildout, possibly even to such a degree that the present local grid will do. In the Netherlands this type of storage is already widely in use (about a hundred thousand flats), it's just not used to store wind energy, because price incentives are not there yet. In the Netherlands this type of system is used for seasonal storage with free heat in the summer obtained from offering cooling services.
@heikogerhauser3908 that's a very different video to the one I made. I was answering my specific question, I wasn't aiming to cover every option at every scale. There are other channels out there that cover that larger scale stuff much better than I could. Just Have a Think, for example ( www.youtube.com/@JustHaveaThink ).
Yes, a fun exercise. The cost of the field might be an issue and I believe the installation might easily be 10 x your estimate. Wire is very expensive these days. Connectivity and inverting would be done differently on that size of arrays. I think the method of payments might be different on such an industrial array. But a fun exercise anyway. Why are you using so much power on heating? Something seems to be wrong but I am sure it will be my understanding.
Heat pump heating. Go check out my stats videos for more details.
Rather off topic.
I've had an ASHP for 14 years. I have no idea about its efficiency as there is no way to monitor or alter anything. The advice now is to run them in a steady state so that they don't cycle too much. My system is 12kw and has large radiators and underfloor heating and is way oversized for my 5 bed house. I am getting air to air installed as well. I think the efficiency should be a lot better than the current system, plus the cooling in Summer will be nice to have. I will still use the current system for hot water plus a little heating. Do you have any idea how to get the best efficiency out of air to air? Is it similar in that it should run for long periods to avoid cycling on and off?
Yes, pretty much the same applies, they're both heat pumps at the end of the day. I've been running ours low and slow (lowest fan setting) and it's been working well so far. I keep an eye on them though, and if I spot them cycling I'll turn them off for an hour or two, then back on once the house has cooled slightly. Our heat pumps are over-specced for our heat loss, so in mild weather they tend to start cycling if I leave them on for too long, so I'd recommend getting a heat loss survey or do your own calculation using Heat Punk, so that you don't run into the same problem (I'm intending to cover this is a future video, actually). Once it gets proper cold they'll probably stay on most of the day without cycling but we'll see how it goes.
Thanks Tim,
The installer has recommended 2 fairly small outdoor units, each supplying 2 indoor units. The smaller units do seem to be more efficient. Like you, we are only going to have them in the most used rooms. I don't think they will be over spec for the room sizes and we can always use the ASHP to compliment them in very cold weather, if needed.
Do not buy anything except the best brands like Fujitsu and Toshiba. The Chinese brands are really inferior at heating although they are decent at cooling. Also if it doesn't bother you you can install floor indoor units which perform better at heating and worse at cooling.
I would buy 2 so you have nearly 30kw if your on grid charge at night for very cheap rate and use only battery during day
EG4-WallMount Indoor Battery | 48V 280Ah | 14.3kWh | Indoor | Heated UL1973, UL9540A | 10-Year Warranty
Most households in the UK wouldn't need anywhere near that amount of storage.
The secret to off grid, is having the space for the solar. Not a crap ton of batteries. When you have 20-30kw of bifacial solar on the ground it does not matter if your system is only operating at 12% of its potential during the grey dismal months. Panels are cheap today when you buy them by the pallet.
Not many people have that amount of land available.
@@TimAndKatsGreenWalk Most people who are "off grid" are on acreages. Not in a city. Where power is easily accessible. And like many people who are off grid today? It cost me less to be self sufficient than what the power company wanted to charge me to bring power 3/4 of a mile into this property.
@@Jamey_ETHZurich_TUe_Rulez Which I already do.
And it's not that much space, about 4 m2 per kW. We've got 650 m2 of land, about half of which is lawn. That's 75 kWp of panels we could put there in the winter. As a trial I put 10 panels on the ground last winter and wired them two each in parallel to a Powerstation. Vastly overpaneling in winter time is no problem whatsoever. We also checked that the lawn didn't mind being covered by panels for approximately three months. One month after removing them the lawn where the panels had been could not be distinguished from the panel free bits of lawn. Panels are down to ridiculously low prices, PV Magazine just claimed 6 cents per Watt wholesale. That's about 50 pounds per kWp or less than 4000 pounds for 75 kWp.
Excess solar could be used to store ballons of hydrogen to run existing gas boiler. Your modeling graph would have to be reconfigured to factor that in. Good luck working out those stats
That is a very unlikely scenario. Great if you could do it, but that would be a lot of extra costly equipment and a dangerous thing to do.
More realistic would be to buy a battery big enough to totally offset your daily consumption all year with cheap electric and see what the numbers say then.
We are in the process of moving to this as part of a house renovation.
Yes, exactly, that'd be a more sensible strategy.
@TimAndKatsGreenWalk I did a quick calculation for myself last year and calculated that I'd need about 2000 kWh of batteries to get through the winter on excess solar generation from the summer months. Not realistic.
Based on a similar situation to yours, with 10.5 kWhp PVs generating 8500 kWh per year and consumption at 9700 kWh per year. This includes charging my EV.
Maybe I could lower consumption slightly by installing a Mixergy or ASHP water tank, instead of instant heated water, but I don't think that would make a big difference.
I also didn't take power leakage into account, which I'd expect when batteries need to store energy for 6 months.
@@FoxInClogsyou wouldn’t need to store all 2000kwh at once though? I suspect most people would use less than 50kwh a day so having a battery of that size and charging with combination of cheap rate electric and solar.
Should the calculation take into account if you can get three phase Power?
Scottish and Southern electricity networks have advised us we can have 11kw total PV
Which i believe is sufficient for 1 tesla 2 battery (Output 5kw) and 14 (south facing) Solar panels (approximately 6 kw) total 11kw (we currently have 1 tesla 2 battery at 12 solar panels (430W each)) - so we are looking to add two additional south facing panels
I was also looking to add an additional 9 North facing panels in order to try to get to net zero (electricity bill over 12 months)
My solar provider has advised if i wanted to expand this one way would be to move to 3 phase supply this would allow me to treble what is allowed (e.g. to 33kw)
Apparently introduction of three phase power could be £2k if it was close by or £20k if it was at the end of the road (looking to find this out currently)
Obviously wouldn't proceed if it was a £20k cost
Well, the point of the video was to see if being off-grid was feasible, so no phases connected to the grid at all! If you're on-grid then three phases opens up so many options, I'd love to upgrade one day. But definitely staying on-grid!
@@TimAndKatsGreenWalk
Have to say I am really enjoying using you excel spreadsheets
One other approach might be to calculate KW requirements for 12 months of the whole system and then to expand the PV system so over 12 months the total cost is net zero (including what you can sell back to the grid). You may have done this already.
Last year (prior to solar panels and battery) my KW usage was 8500 KW (but we have AC units) this year it is down to 6500kw
In my case looking to add 2 further south facing panels and 9 north facing panels to generate 6500 kw or more. However now pushing up to the 11KW limited (specified by Southern Electric) hence my question on three phase supply.
Has your electricity supplier limited you to a maximum wattage?
@@TimHolland-j8j our current limit is 5 kW but the DNO said off the record that I could probably go to to 7 without any problems. I would do that if I ever go ahead with my plans to get more panels on my North roof.
@@TimHolland-j8j I have a single phase power supply, and an export limit of 11.68kW. Consists of a 3.68kW inverter and an 8kW inverter. I now have 15.5kWp of panels, adding more panels doesn't require an increase in the export limit, it's the sum of the inverters that matter. I am gas and electric negative, looking like two years in a row now, and I didn't have as much PV last year.
@@TheRonskiman My solar installer advises that I am at 10kw already because of (1) 5kw solar inverter and (2) 5Kw tesla inverter. they have contacted SSE to see if the 11Kw limit can be increased
What would you have done in the last 2 weeks of cloud. The battery size would have to have been huge.
Quite.
You need a backup generator in the UK. There simply is no other way.
I think your battery and panel figures are wildly optimistic. Most home batteries come in at about £500 per kWh - not sure about UK but £50 for a 450W panel seems extraordinarily cheap. Plus you'd have to add in another £10K for wiring, breakers, safety equipment etc. I'm not sure where you're getting a 40kW hybrid inverter for £3K either? Remember the inverter has to be able to charge the batteries and be off grid.
Oh yes, absolutely, I was trying to be as generous as possible and it still came out extortionate. I got a lot of these values from Midsummer wholesale, there are actually 40+ kW commercial inverters for less than £3k, amazingly. Although those are not hybrids, as you point out.
The question is ,what is the cheapest way to go off grid in the most innovative way.
Good question! Curious to see what people come up with.
One crusial figure you missed out on was the standing charge. Take that into account and it comes in around 44k as opposed to 45k
Haha! Yeah, totally worth it for that. No idea where you got £1000 for the standing charge though. Closer to £200 per year.
Then pick the company with the cheapest standing charge and island yourself over the winter
But still paying. It would be a small price to pay for missing out on the summer export
We earn almost enough from export in the summer to cover our winter costs with our existing system, and with only a few more panels we'd have a net zero bill. I'm satisfied with that.
Biggest problem is finding land that doesn't shade your ground mounted array where sun coming in at 15 degrees angle isn't shaded! It's not the land the panels take up. It's the 10-20 metres in front to be sure no house or trees shade the panels. You'd need a field or be on a hill!
Yup, another good point.
If space was an issue and the cost of panels is getting pretty low wouldn't it make sense to have more of them, far closer to each other and only a small tilt towards the sun? Instead of a single 450w panel you could effectively have 3.5 panels and surely they wouldn't be less than a third as efficient just because they were flat or almost flat? While there's some big numbers in terms of cost here surely the biggest hurdle is having a small field available to deploy them?!
In my situation I wanted as many panels as they could squeeze on my roof. My installer stated I couldn't go over 8.9 KWp because the DNO wouldn't allow it although I'm not sure how accurate that is. So we ended up with 23 390w panels when I think we could have got another 11 panels on my roof (we've got a big roof). However it's probably a moot point and 8.9 KWp was probably about right because the largest inverter Huawei do is 6 KWh and we do get a fair amount of clipping. Maybe we could pay for a second inverter?
But either way there's zero chance of wanting to go off-grid in order to save ~£130 in standing charges. What I took from this video is more about scaling up the system and one day I'll look into it in the hope that I am allowed to by the DNO and it makes economic sense to do so.
The issue is the height of the sun in the sky, really. You'd get the same power out of flat panels covering the whole area of the ground as you would with fewer tilted panels aligned in such a way as to not cast shadows on the other panels. In both cases the sun is providing the same amount of power over the same area, as long as the panels capture it all. So in that case it'd be cheaper to have fewer panels that are tilted in the optimum way.
In uk average use is 7 to 11k of electricity a day
In the summer. A lot more in winter if you have electrified heating.
Tim, I have a question/idea for a future video. Do it and I promise I'll buy you a coffee....
A friend of mine recently mentioned that he thought his Ohme charger was going to receive a software update to allow bidirectional charging. This sounded a bit nuts to me because I presumed that to do this would need a change in hardware or possible also the cable. Seemed a bit too good to be true to basically get it for free through an update. So is it true? If it is then are other charger brands likely to get it? Is it then feasible that cars could be updated to allow it as well? I'm aware that some cars (BYD) are advertised as being ready for V2H/V2G but again I presumed this was because of some hardware included during manufacture.
I'd realistically put this whole thing on the back burner until we replace our other car which won't be for a pretty long time. But be interesting to know if it could be closer than I thought.
I think you're right. The Ohme (and all other home 'chargers') are just a fancy mains supply. The charger is in the car, and the car's inverter is designed for driving the motor, not back-feeding the grid. V2G normally uses a grid-tied inverter in the 'charger' unit, which (as you say) is a significant piece of hardware. Cars could potentially be designed to use their own inverter for V2G, but none are at the moment.
I think this is possible - I was chatting to a tech guy at the Octopus stand at Everything Electric last month and he said they were working on much the same. I pushed him a bit on this and he effectively said 'Wait and see'. I wondered if he was joking but the idea that some chargers might get an upgrade to do this, would seem to support the idea.
I very much doubt a software update would make a normal EV charger bi-directional, I find that claim highly suspicious! But I'm not an expert so I will make some enquiries.
I don't think you can realistically with solar, now if you had a fast running stream through your land then maybe in combination with solar.
Yup, that'd do it.
I have in addition to my 1,86kWp, 3,64kWp and 1,82kWp two Windmills 2000W and one with 700W.
And with 70,5kWh batteries I just failed a little bit in December...
NOT NICE!
Comming year I get 24 panels 455Wp more, and this should do it in DECEMBER.
Interesting video, makes one think in regards to why aren’t electric companies offering free solar and batteries for households, generating electricity for the grid through households would be cost effective compared with wind turbines, don’t know how much a wind turbine cost not only the actual cost of the item but the running cost with maintenance and doesn’t generate anything when no baked beans or when the wind doesn’t blow , would make a good chart = wind turbine cost let’s say over year by year cost and how many homes with solar and batteries in comparison, as example one turbine cost could be a thousand homes with solar and battery, how much would the grid gain compared which each other , if you look at your house as an example so you’ve got a cost of many things for the chart 14 thousand outlay and how much excess you put back to the grid = times that by the cost of one turbine = how many homes one could get done , I think you would be surprised it might be much more cost effective for the electricity companies or not , can’t think if anyone has even looked at this scenario.
In some respects the good export tariffs nowadays are achieving more or less what you're suggesting, by paying people for their excess. It would be interesting to compare typical wind turbine costs to an equivalent amount of domestic solar though, I agree.
@@TimAndKatsGreenWalk You have the knowledge and capability to do such a chart , actually the more I think of it the more I think nobody has even looked into this , especially when you think the buying power of the electric companies therefore the cost would be a lot less with a big order compared to us just buying an individual unit for one house , if you take your situation at a cost of 14 thousand for one house can you imagine if you put an order in for a thousand items wouldn’t be surprised if it ended up being half that amount , sorry just had another crazy thought = if a thousand households were to buy solar and batteries for their individual homes but purchased them as a group at the same time it also could be half price , can you imagine give an order into a company for 1.4 million for a thousand kits the discount would be enormous, you know people in the industry would be curious to ask them what discount would you get if you put an order in for a thousand units like you have in your house , whoops that’s another chart pending = look at the benefits = keeps you out of mischief.
Didn't companies offer free tariffs to FIT customers at one point?
@@Biggest-dh1vr what for the life of the solar ?
@@KavanOBrien looking back, companies offered free electricity for putting solar on the roof of consumers. The solar panels look to often be passed to the house owner at the end of the contract?
For negative experiences of large solar buying companies, have a look at Spirit Energy's video on Solar Together London?
Of course you would need planning permission to put all those panels in a field (or probably anywhere else).
Yes, indeed, I'm sure you would.
Interesting thought experiment - shows why solar alone will never be a solution for grid decarbonisation. With us all slowly moving to heat pumps electrical usage in winter will dwarf that of summer when solar production will eventually more than meet demands
Luckily we have a lot of wind generation in the UK. And an increasing amount of grid scale battery storage. It requires being on-grid to benefit from it though!
@TimAndKatsGreenWalk I wonder if car to grid will eventually form part of the national infrastructure of battery storage...
@@adamdevine7375 oh, I'm sure of it in the fullness of time. I wish it'd hurry up and become more commonplace!
Maybe 2 sigma would be more appropriate, giving you 95% of the results falling within the normal distribution, or for belt and braces go for 3.
Yes, I considered using two sigma but it was already ridiculous so I left it at one!
I'd say no, because you'll get cloudy days on end that will drain your batteries, and not be able to generate enough to recharge each day.
Today we've generated 3.1 kWh from a 10.5kWp array, while using 11.3 kWh, and have not run the stove, washer or dryer.
Yes, I mentioned that in the video.
How did you get the 11,3kWh?
I have also Heating circulation pumps running 24/7 and also a 320l freezer box, a 80l Freezer and a 250l Fridge but I am under 5kWh (and yes, I switch off my two Laptops and my Workstation)
@@michellekonzack Can't give an exact breakdown, but we have about 300W constantly from 2 freezers and a fridge freezer, computers, lights etc.
Later in the day we also charged our EV, and as that's currently from a 120V external wall socket that adds into the mix, but asn't in this number. Any use the microwave or air fryer also adds in.
Our solar feeds only "essential loads", i.e. those that we would wish to maintain during a powercut, so it excludes the stove, washer and dryer, and will also exclude a 240V 50A socket we will get for the EV level 2 charger.
Late September we did have a couple of days around 5-6 kWh, but most days we top 10 kWh.
Household of four.
Before I even started watching this I thought it would be unrealistic to be able to go off grid from solar alone. You need loads of space and loads of money and most people done have enough of either. Good video though
Indeed, intuitively that was my feeling too but I thought I should probably actually do the sums to be sure. I'm glad my intuition was correct.
@@TimAndKatsGreenWalk Without watching the video as I'm at work, I can also say the answer is no. We have a 50kWp array here at work, and I've seen some very low days. If you can install the same along with a massive battery and your usage is low, then it's possible. Best bet have a piece of land with a decent stream with a good upstream head, you can then generate 1 kW or more 24/7 pretty easily. Add some PV for the summer months if water flow reduces.
Perhaps off grid is possible when we can manufacture 75%+ efficient solar panels. That is sadly a long way off, if it’s even possible
Looks like 40 ish% efficiency is just about doable with perovskite-silicone composite panels. Those might be just around the corner for domestic customers (around the corner being a few more years at least, I suspect).
It is already possible, but you have to get rid of the AC/HeatPump and also cook with Propane in the Winter (in the summer I use my Induction Stove)
@ It will depend on your power usage as well as location. We have two EVs and without resorting to public charging it would be impossible to run those off grid 365 days a year without a grid connection. Yes I could get rid of the EVs but the savings I make from not buying petrol or diesel each week pay for my entire grid energy cost, both gas and electricity.
In spring I start rebuilding a russian UAZ 3303 into a 48V EV with a Victron Multiplus-II 48/10000 and ~62kWh of LiFePO4 Batteries.
In the summer I will NEVER need a public charging station, but in the winter I charge on a public charging station and can even save the money for a noisy generator at home if necessary...
Bit weird not doing it for 'your array'. Let alone making up a ground mounted rare array type. All very well saying a perfect set up up and plenty of land to spare you 'could'. Plus too much wittering on about the costs, which are irrelevant, the point was 'can' you go off grid in the UK!
There also is the option of some other form of winter heating. Even a generator to pick up the mid winter slack.
More usage reduction needed!
My electricity bill estimates about 2000kwh a year. No gas available.
Well if money's no object, and land's no object, well of course you can 🙂
I believe I made my point in the video quite clearly.
Nope, the only way to do this is via an oil bivalent system
Well, there are more ways than that, but yeah, very tricky to do with just solar and batteries.
@@TimAndKatsGreenWalk anything is possible, but at what cost! - you'll see this daily from the political hierarchy in their 4x4's / oil driven houses. Do as we say not as we do?
Why is everyone laying these panels out in rows on the floor. Why not just lift the entire rows up into a skinny tower?
Ease of installation and maintenance.
A skinny tower surmounted by a wind turbine in a lake covered with solar behind a dam on a hill?
Thankyou for the silly nonsense 👍🏻
Always a pleasure.
ere no
Indeed
Your video reminded me of this video from a couple that IS off grid (in north Idaho) and uses a generator in December, but STILL gets more than half their electricity from solar…. th-cam.com/video/fv68DWKQ9zA/w-d-xo.html
You can do anything you like off-grid if you're willing to supplement with a generator. I was trying to avoid that in my scenario.
That was interesting. Not realistic for the vast majority of people.
Absolutely. If everyone tried to do that we'd rapidly run out of land!