Solar or wind combined with an energy storage technology must be evaluated as a package deal; if, making a comparison of costs, or advantage/disadvantage with our legacy power generation.
Of course a generation system with units on spinning-hot standby, producing no power but burning fuel, will be less efficient.
That’s exactly right. Also, if less efficient gas or coal generation equipment has to be installed to accommodate the wind and solar, that also has to be part of the overall calculation. This issue has particularly become evident in areas where they have gradually got rid of the coal and replaced it with gas….. unfortunately, a lot of that gas is using open loop instead of combined cycle technology because they need it to be able to come on line in a hurry if the wind or solar suddenly stops. The difference in efficiency between open loop and combined cycle is about 20% in efficiency. What this means is that if only combined cycle technology was used, the increase in efficiency over open loop is so great that the wind and solar don’t really provide a contribution at all……