Ridenbaugh Press/Northwest

There’s a tendency to think that conservation is something that helps only at the edges, if there. But it can amount to more than that. What’s more surprising is how much it evidently has amounted to already.

From the Northwest Power & Conservation Council, which recently oversaw a study on electric power conservation in the region:

Improved efficiency reduced demand for electricity in the Northwest in 2008 by an amount equal to the power use of about 148,000 homes, the highest annual accomplishment since recordkeeping began 30 years ago, according to the Northwest Power and Conservation Council.

The 2008 efficiency improvements — energy conservation — totaled 234 average-megawatts (an average-megawatt, a unit of electricity measurement, is 1 million watts delivered continuously for a year). That is equal to the output of an average-size natural gas-fired power plant.

Efficiency improvements have a cost, but it is lower than the cost of building new power plants. In 2008, the average cost of efficiency for the region’s electric utilities was just $20 per megawatt-hour (2 cents per kilowatt-hour), or approximately one-fifth the cost of power from a new generating plant fueled by either natural gas or wind. Total spending by the region’s electric utilities to achieve the improved efficiency was $251 million or just 2.2 percent of regional retail electricity revenues.

The report isn’t absolute: It comes from 64 reporting electric utilities, to 51 that haven’t reported yet. (You didn’t think there were that many in the Northwest, did you?) But pretty indicative of the potential.