According to the Wall Street Journal, already weathering losses from the economic downturn, power companies are bracing themselves for what could possibly be a permanent change in consumer consumption patterns. Figures from a sample of major utilities across the country reveal a sharp decline in power use among households and businesses.

Xcel Energy experienced a 3 percent drop in home-energy use from August 2008 through September 2008, while Duke Energy experienced a 9 percent decline in usage among residential customers. In the Midwest, Duke posted a 5.9 percent drop in electricity sales in the third quarter.

Experts say the drop in consumption will be difficult for U.S. utilities to absorb because they traditionally rely on sales growth of 1 to 2 percent per year to underwrite expansion plans to meet the demands of a growing population.

“We’re in a period where growth is going to be challenged,” said Jim Rogers, Duke Energy chief executive officer.

As it is, utilities have committed to investing $1.5 trillion to $2 trillion by 2030 on upgrades for their electric systems.