“Electric power markets in the United States are undergoing significant structural change that we believe, based on planning data we collect, will result in the installation of the ability of large-scale battery storage to contribute 10,000 megawatts to the grid between 2021 and 2023—10 times the capacity in 2019.”
How much is 10,000 megawatts? What is a megawatt?
A watt is a measure of electric power. A 60-watt light bulb uses 60 watts of power. A 60-watt bulb lit for one hour uses 60 watt-hours of electricity. A typical home refrigerator uses 350 to 780 watts.
A kilowatt is 100 watts. A megawatt is 1,000 kilowatts. A megawatt-hour (MWh) is 1,000 kilowatt-hours.
An average American home uses about 10,700 kilowatt-hours in a year, or about 880 KWh per month.
Large storage batteries are now being installed as a part of solar installations. The electricity generated by solar panels may be stored in the battery when demand/prices are low and sold into the grid when demand/prices are high. Most battery systems being installed in the US today are appurtenant to solar farms.
Battery storage systems use the same lithium-ion batteries developed and used for electric vehicles, just on a much larger scale.
It takes energy to store electricity. About 15% of the electricity stored in a battery is lost when the electricity is discharged.
A battery can supply electricity only as long as it has electricity to discharge. A 400-megawatt battery storage system is being installed at California’s largest gas-fired power plant, the Moss Landing Power Plant overlooking Monterey Bay. The batteries will be able to discharge enough electricity to power about 300,000 California homes for four hours.
These large-scale battery systems are a solution to the unreliability of solar and wind power. Without the ability to store electricity generated by solar and wind, back-up generators must be able to come online quickly to replace power lost when the wind doesn’t blow and the sun doesn’t shine. Natural-gas generator systems become more expensive to operate because they have to cycle on and off more frequently.
The Electric Reliability Council of Texas (ERCOT) is the grid operator for most of the Texas electric grid. We all learned a lot about ERCOT as a result of last February’s freeze. ERCOT projected 86,000+ megawatts of expected peak demand this summer. The previous record was 74,820 MW on August 12, 2019. The peak demand on August 15, 2021 was 73,821 MW. There are some 25,000 MW of “installed wind capacity” (when the wind blows) in ERCOT, 3,850 MW of installed solar capacity, and 225 MW of installed battery storage capacity.
California is the leader in solar capacity, but Texas is catching up. In 2020, solar comprised only 4 percent of Texas’ generating capacity. According to the EIA, Texas will add ten gigawatts (10,000 megawatts) of utility-scale solar power in 2021 and 2022. Most of those solar power projects will probably have battery systems. Solar is booming in Texas in part because of a 26% federal tax credit for solar projects started in 2021 and 2022. The credit drops to 22 percent in 2023 and 10 percent in 2024.