Renewables Test IQ of the Grid

摘要

In the afternoon of 26 February 2008, the winds died down in a stretch of west Texas that's home to thousands of tall wind turbines. Over a span of 3 hours, the turbines' contribution to the state's electricity grid fell by 75%. That 1500-megawatt (MW) drop-equivalent to the output of three midsized coal-burning power plants-coincided with a spike in demand. At 6:30 p.m., the alternating current in the state's transmission lines started to alternate more sluggishly, an ominous signal that the system was approaching collapse.