Wall Street Journal: As residents of the East Coast cranked up their air conditioners in last week's stifling heat wave, utility officials turned not only to every available power plant but also to increasingly popular "demand response" programs that reward customers for cutting power use at peak times.
In the energy world, where units of electricity are measured in "megawatts" or millions of watts, these peak-time conservation efforts are said to provide valuable "negawatts" that help cushion the electric grid against...