Wind power – What about transmission line losses?

Secretary of Energy Dr. Steven Chu spoke yesterday at Dartmouth College, near my home town of Norwich, Vermont, and our local newspaper quoted him as saying that China’s electric transmission system can carry power farther and more efficiently and that by contrast, U.S. transmission lines lose "as much as 80 percent of energy when transmitting electricity over long distances."

Now of course, it’s not always easy to know what was actually said and perhaps reported inaccurately. But since the question of transmission line losses has come up occasionally in the past, and anti-wind individuals have questioned whether electricity can be transmitted efficiently from windy rural areas of the U.S. to population centers, we’d like to set the record straight.

The U.S. utility system contains two general types of power lines, transmission lines and distribution lines. Distribution lines, as the name suggests, are used to distribute electricity from substations to end users–they generally are far more numerous, run for shorter distances, and use lower voltage, while transmission lines operate at higher voltages and are used to carry electricity for long distances. According to the U.S. Department of Energy, total line losses for the entire electric utility system, both transmission AND distribution, in 2007 were just 6.5 percent.

As American Wind Energy Association and the Solar Energy Industries Association have previously urged, our nation needs a new system of transmission lines that can not only deliver renewable energy to population centers, but strengthen America’s outdated and over-stressed transmission system and improve its reliability to benefit all customers.

By Tom Gray,