…Critical Reserve Margins…
Are reserve margins for the grid a quaint idea from the past? One would think so, given how RTO/ISOs are approaching the question.
Reserve margins are supposed to ensure there will be sufficient generating capacity even if demand suddenly and unexpectedly surges.
This could happen during a heat wave when the use of air-conditioning increases. See, Wind Power Threat http://wind power threat
As mentioned in the last article, ERCOT has seen its reserve margin become dangerously low, at 7.4%. In the past its reserve margin was 13.75%.
But, what is the reserve margin when wind and solar are added to the grid?
How can they be included as a reserve for use in an emergency when the reserve might not be there? As the last article explained, power from wind might not be available if there are freezing temperatures, or if it’s too hot. Or, when the wind isn’t blowing.
Power might not be available from solar when skies are cloudy for several days.
There have been attempts to use probabilistic analysis to estimate how much of installed wind and solar capacity should be included in the reserve. Though based on probabilities, it’s still only an estimate.
The only certain method would be to exclude wind and solar from any reserve margin.
The accompanying chart shows how much new build will be required in ERCOT’s territory to ensure a safe grid without blackouts. But how much of the new build can be wind or solar while still maintaining a safe grid?
ERCOT has said that the 10% of new build required in 2020 will be from new wind installations. Are they really counting on wind to provide sufficient reserve to bring the reserve back to 13.75%? A reserve that is only 3.5% if the wind doesn’t blow? And what about the following years? How safe will Texans be from blackouts when there is a negative reserve, i.e., shortfall?
The purpose of the reserve margin is to guarantee that electricity will always be available, barring system failures, so that there won’t be blackouts. But, any reserve based on estimates, no matter how scientifically made, can’t make that guarantee.
This is just another way in which wind and solar make our lives less safe.
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