EnergyGrid-scale batteries for storing renewable energy have large carbon footprint
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. A key problem is that the U.S. electrical grid has virtually no storage capacity, so grid operators cannot stockpile surplus clean energy and deliver it at night, or when the wind is not blowing. Stanford scientists have developed a novel way to calculate the energetic cost of building large batteries and other storage technologies for the electrical grid. The found that the fossil fuel required to build these technologies could negate some of the environmental benefits of installing new solar and wind farms.
Americans take electrical power for granted whenever they flip on a light switch. 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 cannot stockpile surplus clean energy and deliver it at night, or when the wind is not blowing.
To provide more flexibility in managing the grid, researchers have begun developing new batteries and other large-scale storage devices. A Stanford University release reports that according to Stanford University scientists, the fossil fuel required to build these technologies could negate some of the environmental benefits of installing new solar and wind farms.
“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 storage to help balance supply with demand. To our knowledge, this study is the first to actually quantify the energetic costs of grid-scale storage over time.”
Pumped hydro
The total storage capacity of the U.S. grid is less than 1 percent, according to Barnhart. What little capacity there is comes from pumped hydroelectric storage, a clean, renewable technology. Here is how it works: When demand is low, surplus electricity is used to pump water to a reservoir behind a dam. When demand is high, the water is released through turbines that generate electricity.
For the Stanford study, Barnhart and Benson compared the amount
