Generating electricity with solar panels and wind turbines is now cheaper than using coal or natural gas. Wind and solar energy were emerging technologies with minimal market share in 2000, but they are now the fastest growing sources of electricity in the US. According to the Solar Energy Industries Association (SEIA), solar energy represents 43% of capacity added in 2020, while wind energy represents 38%. Together, both technologies represent 81% of new electricity generation in the US.
California is the top solar state with 31.3 GW installed, while Texas is the top wind state with 31 GW. As of early 2021, the US has 97.2 GW of solar power and 122.4 GW of wind power. This means that California is home to 32% of solar capacity, while Texas has 25% of wind capacity.
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Like any technology, solar panels and wind turbines have limitations. They can only generate electricity when their respective resource is available – sunlight or strong wind. Solar and wind energy can help reduce electricity costs, but they must be combined with other sources, such as hydropower and fossil fuels, to ensure a reliable energy supply. Combining solar panels and wind turbines with batteries is also a promising concept, but energy storage applications are still limited by their high cost.
Solar energy: the fastest growing source of electricity in the US
Despite the COVID-19 pandemic, 2020 was a record year for the US solar industry. The new capacity added was 19.2 GW, bringing the total to 97.2 GW. As the 26% federal tax credit for solar energy has been extended for two years, this growth is expected to continue. According to SEIA, the solar generation capacity installed so far in the US can produce electricity for 17.7 million homes.
- Utility-scale solar farms represent the majority of new capacity, with nearly 14 GW deployed in 2020. The project backlog is even larger, with 69 GW in development and construction.
- Domestic solar grew by 3.2 GW, while the non-residential sector grew by 2 GW.
Solar energy is affected by economies of scale and project costs decrease as installed capacity increases. According to the latest SEIA data, the average cost is $2.83/watt for home solar, $1.36/watt for non-residential solar, and $0.78/watt for solar utilitarian. When single-axis tracking is added, the cost of solar power increases to $0.91/watt.
California added the most solar capacity of any state, with 3,904 MW of new installations in 2020. However, Texas is close behind with 3,425 MW. Florida came in third with 2,822 MW, while Virginia came in fourth with 1,406 MW. These were the four states that added more than 1,000 MW of solar energy in 2020, among 27 that added more than 100 MW.
Wind Energy: A Second Place After Solar Energy
Wind and solar energy are often mentioned together, and both production methods produce cheap electricity with virtually unlimited energy consumption. However, there are also important differences between solar panels and wind turbines. Solar panels are cost-effective on projects of all sizes, while wind turbines need a certain scale to be viable. Furthermore, solar panels can be used on any unshaded roof with the structural capacity to support them, while wind turbines are very demanding in terms of site conditions.
Wind power had the 2nd highest growth among all US electricity sources in 2020, with 16.9 GW of new capacity added, reaching 122.4 GW in total. Texas continues to be the leader in wind energy, with 4,235 MW added in 2020. However, there were other states that also deployed more than 1,000 MW of wind capacity last year:
- Iowa = 1,498 MW
- Wyoming = 1,123 MW
- Illinois = 1,029 MW
- Missouri = 1,028 MW
Onshore wind represents almost all installed capacity so far, and the US has just 42 MW of offshore wind at the beginning of 2021. However, the US has considerable offshore wind resources , and there are already 26 GW of projects underway . The Atlantic Coast has most of the U.S. offshore wind generation potential – potentially 4.6 billion kWh per year.
Conclusion
The US still gets 60% of its electricity from fossil fuels, according to the latest data from the US EIA . Wind and solar energy represent 8.4% and 2.3%, respectively, but are growing rapidly. They represent 81% of all new capacity added in 2020, while fossil fuels and all other sources represent the remaining 19%. With tax incentives and decreasing technology costs, this trend is expected to continue.
