Americans take electrical power for granted whenever they flip on a light switch. But the growing use of solar and wind power in the United States makes the on-demand delivery of electricity more challenging.
A key problem is that the U.S. electrical grid has virtually no storage capacity, so grid operators can't stockpile surplus clean energy and deliver it at night, or when the wind isn't blowing.
To provide more flexibility in managing the grid, researchers have begun developing new batteries and other large-scale storage devices. But the fossil fuel required to build these technologies could negate some of the environmental benefits of installing new solar and wind farms, according to Stanford University scientists.
"We calculated how much energy it will cost society to build storage on future power grids that are heavily supplied by renewable resources," said Charles Barnhart, a postdoctoral fellow at Stanford's Global Climate and Energy Project (GCEP) and lead author of the study. "It turns out that that grid storage is energetically expensive, and some technologies, like lead-acid batteries, will require more energy to build and maintain than others."
The results are published in a recent online edition of the journal Energy & Environmental Science.
Most of the electricity produced in the United States comes from coal- and natural gas-fired power plants. Only about 3 percent is generated from wind, solar, hydroelectric and other renewable sources. The Stanford study considers a future U.S. grid where up to 80 percent of the electricity comes from renewables.
"Wind and solar power show great potential as low-carbon sources of electricity, but they depend on the weather," said co-author Sally Benson, a research professor of energy resource engineering at Stanford and the director of GCEP.
"As the percentage of electricity from these sources increases, grid operators will need energy sto
|Contact: Mark Shwartz|