Keeping the air conditioners on for eastern utilities are "dozens of 1950s and 1960s coal-burning power plants that dump prodigious amounts of acid gases, soot, mercury and arsenic into the air. Because of new Environmental Protection Agency rules, and some yet to be written, many of those plants are expected to close in coming years."
To be sure, the EPA and private industry differ as to how many coal plants will need to be shuttered due to the new regulations. It could be as low as 1% or as high as 7%. Key will be getting natural gas plants opened to replace them because renewable power has its limitations.
"So much of the generating capacity added around the country lately is wind power, which is almost useless on the hot, still days when air-conditioning drives up demand." One utility assessed "a 100-megawatt wind farm as being worth only 13 megawatts on a peak summer day."