Not long ago, grid operators only had to worry about coal, nuclear, natural gas and big hydro as sources of electricity generation. Except for the pollution, the threat of radioactive disaster, and blocking rivers, it was a simpler, more innocent time.
A day-ahead schedule with an hourly real-time update of dispatch in response to unexpected rising and falling demand worked fine for grid operators. The only forecasts they had to worry about were planned maintenance and major changes in weather.
Continued reliance today on such antiquated grid operating standards amounts to de facto discrimination against variable renewables like wind and solar.
To integrate variable renewables into a transmission system, sub-hourly scheduling and dispatch of generation, based on detailed forecasts of renewable resources and the state of the older power plants, is vital.
“Many of these grid operating practices were put in place decades ago to accommodate peculiar attributes of the fossil, nuclear, and hydroelectric power plants that made up nearly the entire generating fleet at the time,” the American Wind Energy Association (AWEA) and its allies wrote last fall in pre-decision comments on proposed rule changes by the Federal Energy Regulation Commission (FERC). “Attempting to fit variable renewable energy resources into these operating practices is often like trying to fit a round peg into a square hole.”