Renewable Storage solved with Australian Sand - Part 02

This concept is based on the Masdar research which uses parabolic mirrors to focus light on a small area to heat sand, that falls through a cylinder. It then uses that heat as a store for future production of power. See article on later page
Sand can easily flow as in an hourglass. Sand can be very easily heated requiring only one fifth of the energy to heat compared to water. This heat is also given up easily.
Colder sand would come from a reservoir, lifted to a heat exchange tower, and be percolated through electrically heated furnaces, absorbing enough heat to reach 600 degrees or more depending on the quantity of electricity available at the time. Heat control is achieved by regulating sand flow.
This is then stored until required.
When needed, this heated sand is elevated to a heat exchange tower where it passes around channels of steam pipes. The relatively cool steam at 100C comes in the bottom of the tower and is superheated by the sand, reaching about 600-800C by the time it is discharged at the top. The steam is then in a supercritical state, ideal for generators. Heat control is achieved by regulating sand flow. At the turbines, the ideal temperature is about 550C.
The sand depleted of heat is returned to the cold reservoir where it remains at about 100 C.
Regulating the flow of sand, electricity and steam will establish control.
This system required very few moving parts, no mechanical or electrical systems that need to be invented and should cost a tiny fraction of batteries or hydro power.
It can easily be positioned at an existing power station using its turbines as well as its cooling systems.
It occupies an area 100mx100m (1 hectare) and 20-40m deep , buried at a depth of a few meters under a cover of sand, sufficient for total insulation.
Sand at 600C in an area of 1 hectare and 20 m deep (300,000 tons) can hold renewable energy the equivalent of 4,500 tons of coal or 10,000MWh: at 40m deep the equivalent of 9,000 tons of coal or 20,000MWh.
By comparison, the Tesla Battery in South Australia has a capacity of 129 MWh and the King Island battery 1.5MWh
All the surplus power production from wind, tide and solar can be stored in the sand and thus, not wasted. Eventually it would allow coal and gas to be mostly phased out
It is safe,
Sand of many types are suitable
It is environmentally friendly,
No toxic materials are used,
Recycling poses no problem
It is fraction of the cost of any other system.
It retains its heat over long periods of time.
It requires no new technology
Sand heated by renewable energy to 600-800 C contained with one hectare and 40M deep hold the heat equivalent of over 9,000 tons of coal.