Urban Trees and Electric Utilities

The Washington Post today has an interesting story on the environmental and economic value of planting street trees, highlighting Sacramento's progressive approach:

About 375,000 shade trees have been given away to city residents in the past 16 years, and there are plans to plant at least 4 million more. To receive up to 10 free trees, residents simply call the Sacramento Municipal Utility District, a publicly owned power company.
"A week later, they are here to tell you where the trees should be planted and how to take care of them," said Arlene Willard, a retired welfare case worker who with her husband, John, has planted four SMUD trees in the back yard of their east Sacramento house.

Why would an electric utility be interested in planting trees?

Sacramento's shade crusade easily pays for itself, with summertime energy savings about double what SMUD spends on trees each year. As they mature, trees already planted by the utility are expected to save enough electricity to power about 14,000 homes.
By planting 10 million trees and fabricating lighter-colored roofs and pavement, Los Angeles could reverse an urban "heat island" effect -- caused by concrete, asphalt and heat-retaining buildings -- that has been increasing for a hundred years, according to a simulation study by the Department of Energy's Lawrence Berkeley National Laboratory. It found that Los Angeles could lower its peak summertime temperature by five degrees, cut air-conditioning costs by 18 percent and reduce smog by 12 percent.

The reduction in power demand due to planting trees will not show up on a power utility's balance sheet. Utilities measure their output in kilowatt hours, but strategies that reduce peak demand can be just as effective in meeting their customers' needs, and more cost effective in terms of capital investment.