The lowest electricity prices in more than a decade are testing the whole business model of independent power-generation companies. While most companies are thrilled when their fuel costs drop, plunging natural-gas prices have pushed wholesale electricity prices down to rock-bottom levels. That trend is pressuring the sales and stock prices of some of the biggest power-plant owners in the U.S. A U.S. Supreme Court decision this week put additional pressure on generators’ stocks with a ruling that allows big consumers to receive payments for cutting their electricity use that are equivalent to what generators are paid to make electricity. “It’s a tough time for merchant power companies,” said SunTrust energy analyst Ali Agha. Independent power companies came to the fore in the 1990s when many states deregulated their electricity markets. Merchant generators own power plants and sell the electricity they make to big industrial users and utilities. The companies […]