On cloudy days, large PV plan can supply its full power, for example 100 MW, and in less than one minute drop to 30 or 20 MW with a cloud. Very often, the full power is back five or ten minutes after the event; a nightmare for the grid manager.
The solar thermal plan harnesses the energy of the sun more efficiently, but the production of electricity pass trough a thermal cycle that is less efficient. The advantage of this thermal transition of the energy is the stability of the process. In a cloudy day, the total production of the electricity will of course be lower, but the process will stay constant and reliable for the grid. On sunny days, the system can store heat, an easy process, and deliver some electricity on the evening or at early peak hours the day after.
Wind-Do is a midscale wind turbine concept that permits a very low installation cost per MW of power. This allows the design of over capacity wind farms that can deliver 50 to 60% of their nominal power to the grid. (Beside 30 to 40% for recent giant wind turbines ones.) This over capacity makes available a significative amount of electricity that is produce, but that cannot be deliver to the grid. As the power sells to the grid pay all the operation expenses, if used, this over capacity is free energy.
Store electricity via batteries is efficient, but very expensive, in good part because of the relatively short lifetime of batteries beside other energy facilities. This system cost from 15 to ¢25 to store and return a KWh of electricity; even free electricity cannot use this as a viable storage business model.
Beside that, a steam turbine will have a low efficiency of 50% (a little less in reality) that alone is of low interest to store electricity. Now consider an existing steam system that is underused. Adding energy to increase the utilization of the system is then at no cost in terms of investment and operations. This means that a 5 ¢/KWh electricity that is transform in heat will produce a 10 ¢/KWh electricity cost in return, and by extension free input end by free output as there is no fix expenses to assume.
Imagine now the following scenario: Wind-Do wind farms are comfortable to sell their electricity at 6 ¢/KWh. The owner of a wind farm propose to sell his energy to the grid at ¢9 on the eight peak hours of the day, at ¢6 in the middle of the day and at ¢3 on the night. The wind farm sell its over capacity to the thermal solar farm at ¢3, adding most of its night production if useful. The solar system can reused this energy to produce electricity at ¢6 cost and sell it to the grid as wind energy at ¢9 on peak hour.
The grid manager is happy to have a very reliable source of electricity at peak hours, including in winter when there is less light but more wind. The wind farm sell its over capacity at 3 ¢/KWh, a significative net benefit. If we include all the night electricity, up to 50% of the wind production will be sale for storage. The solar plan enhance the profitability of its energy process for a very small investment, and can propose to the grid manager an above 95% availability of its full power at peak hours.
The perfect match !