Renewable energy is power from sources that nature refills on a human timescale: sunlight, wind, moving water, heat from inside the earth, and plant material. Unlike coal, oil and natural gas, these sources do not run out when we use them. In 2025, they produced about 24% of utility-scale electricity in the United States, according to the U.S. Energy Information Administration’s breakdown of US electricity by source.
The rest of this guide covers how each type works and how much power it supplies. It also looks at California’s clean electricity law and the real trade-offs, plus what a household can actually do. For more explainers like this one, see our science and technology guides.
What counts as renewable energy
The test is simple. If a source is replaced by natural processes about as fast as we use it, it is renewable. The sun will keep shining and the wind will keep blowing no matter how many panels or turbines we build. Rivers also refill with rain and snowmelt. Forests and crops regrow.
Fossil fuels fail that test. Coal, oil and gas formed from ancient plants and animals over millions of years, so every ton burned is gone for good. Nuclear power sits in its own group. It produces almost no carbon dioxide while running, but its uranium fuel is mined and finite, so the EIA does not count it as renewable. That is why you will often see two separate terms: “renewable” and the wider “clean” or “zero-carbon,” which also includes nuclear.
The five main types and how they work
Solar
Solar panels are made of photovoltaic cells, usually silicon. When sunlight hits a cell, it knocks electrons loose and creates a direct current. An inverter then turns that into the alternating current your home and the grid use. Solar works on rooftops and in large desert fields alike. Its obvious limit is that output drops to zero at night and falls on cloudy days.
Wind
A wind turbine is a large propeller on a tall tower. Moving air spins the blades, which turn a shaft connected to a generator. Taller towers reach steadier, faster wind, which is why modern turbines keep getting bigger. Wind is the largest renewable source of electricity in the US. Most of it comes from the Great Plains and Texas, where wind is strong and land is open.
Hydropower
Hydropower uses falling or flowing water to spin turbines. Most of it comes from dams that hold back a reservoir and release water through the plant. Because operators can choose when to release water, hydro can follow demand during the day. That said, output depends on rain and snowpack, so drought years cut it sharply. Large dams also change river habitats for fish.
Geothermal
Geothermal plants tap heat from deep underground. Wells bring up hot water or steam, which drives a turbine. The cooled water is then usually pumped back down. Unlike sun and wind, geothermal runs around the clock. However, good sites are rare and concentrated in the West. California’s Geysers field north of San Francisco is one of the largest geothermal complexes in the world.
Biomass
Biomass means burning or processing organic material for energy. Examples include wood waste, farm residue, landfill gas and ethanol made from corn. It counts as renewable because the plants regrow and absorb carbon again. Still, it is the most debated type. Burning biomass releases smoke and carbon right away, and the climate benefit depends on how the fuel was grown and how fast it is replaced.
How much US electricity comes from renewables
In 2025, renewables made about 24% of the electricity from US utility-scale power plants, per EIA data. Still, natural gas was the largest single source at about 41%. Nuclear supplied about 18% and coal about 17%. However, these shares cover large plants only. Rooftop solar on homes and businesses adds more on top of them.
| Source (2025) | Share of US utility-scale electricity |
|---|---|
| Wind | about 11% |
| Solar | about 7% |
| Hydropower | about 6% |
| Biomass | about 1% |
| Geothermal | less than 1% |
| All renewables | about 24% |
| Natural gas | about 41% |
| Nuclear | about 18% |
| Coal | about 17% |
Solar is the fast mover. As recently as 2023 it supplied under 4% of utility-scale generation, so its share has nearly doubled in two years. Companies are part of that growth, because many sign long-term contracts to buy power straight from new projects. In 2017, for example, the Rock Falls wind project in Oklahoma began operating to supply a consumer goods company.
California’s share and the 100% clean electricity goal
California is well ahead of the national average. In 2023, 67% of the state’s retail electricity sales came from renewable and zero-carbon sources, up from 61% a year earlier, according to a July 2025 announcement from the governor’s office. Solar, wind and other renewables made up 43% of that. Large hydro and nuclear then added about 12% each. The state also had more than 15,000 megawatts of battery storage at the time.
The legal target comes from Senate Bill 100, signed in 2018. It sets a policy that renewable and zero-carbon resources supply 100% of retail electricity sales by the end of 2045. It also requires 60% from eligible renewables by 2030. A later law, SB 1020 (2022), added interim clean electricity goals of 90% by 2035 and 95% by 2040. As of October 2026, those targets remain state law. Note the wording, though: “zero-carbon” lets large hydro and nuclear count toward 2045, not just sun and wind.
Pros and cons of renewable energy
The case for renewables rests on a few plain facts. They burn no fuel, so running costs are low and there is no fuel price to spike. Wind, solar, hydro and geothermal release almost no carbon dioxide or air pollution while operating. Also, sunlight and wind are domestic, so they cannot be cut off by a foreign supplier.
Cost has moved fastest. Lazard’s 2026 analysis of the levelized cost of energy, which spreads a plant’s full lifetime cost over each megawatt-hour, puts new utility-scale solar at roughly $40 to $98 per MWh without subsidies. Onshore wind comes in at roughly $37 to $99. New gas combined-cycle plants cost about $51 to $129. Lazard also notes that costs rose across every technology this year. Even so, the Lazard LCOE+ report still finds renewables the cheapest new-build option on an unsubsidized basis.
The downsides are real too:
- Intermittency. Solar stops at sunset and wind comes and goes. So the grid needs backup from gas plants, hydro, imports or batteries.
- Storage cost. Batteries are spreading quickly, but most grid batteries cover about four hours. Pairing solar with storage pushes Lazard’s range up to about $61 to $156 per MWh.
- Land use. Solar farms and wind farms need far more land per unit of power than a gas plant. Siting fights over deserts, farmland and views can delay projects for years.
- Transmission. The best wind and sun are often far from cities. But new power lines are slow to permit and build.
- Materials. Panels, turbines and batteries need mined metals, and recycling them at scale is still developing.
Renewable energy vs non-renewable energy
| Renewables (solar, wind, hydro, geothermal) | Fossil fuels (coal, oil, gas) | |
|---|---|---|
| Supply | Refilled by nature | Finite, formed over millions of years |
| Fuel cost | None (biomass is the exception) | Ongoing, and prices swing |
| CO2 while running | Near zero | High |
| Available on demand | Hydro and geothermal yes; solar and wind vary | Yes |
| Land per unit of power | Higher | Lower at the plant, plus mining and drilling |
| Unsubsidized cost of new power (Lazard 2026) | About $37-99/MWh for wind and solar | About $51-129/MWh for gas combined cycle; $72-177 for coal |
What households can do
Most people do not need to build anything to use more renewable power. So start with your utility. Many offer a green power plan, and many Californians are served by community choice programs with higher renewable content. Check your bill or the provider’s power content label, which shows the actual mix you buy.
If you own your home, rooftop solar is the bigger step. Prices vary a lot by roof, state and installer, so run the numbers first. Our guide to solar panel costs in 2026 walks through current price ranges. Keep in mind one recent change: the federal 30% residential clean energy credit ended for systems installed after December 31, 2025, per the IRS guidance on the 2025 tax law. State and utility rebates may still apply.
Smaller steps also help. Run the dishwasher, laundry and EV charger in the middle of the day when solar output is high. In practice that also saves money on time-of-use rates. Then cut waste first, with LED bulbs, a smart thermostat and better insulation, because the cheapest kilowatt-hour is the one you never use.
Read next
Frequently asked questions
Why is renewable energy important?
It cuts the carbon dioxide and air pollution tied to burning fossil fuels. It also has no fuel bill, which protects against price spikes. And because sun and wind are local, it reduces dependence on imported energy.
Is nuclear power renewable?
No. The EIA classes it as non-renewable because uranium is mined and limited. However, it emits almost no carbon while running, so California’s SB 100 counts it as zero-carbon.
What is the most used renewable energy source in the US?
For electricity, wind is the largest, at about 11% of utility-scale generation in 2025. Solar was next at about 7%, followed by hydropower at about 6%.
Can a country run on 100% renewable energy?
Some grids already come close for hours or days at a time. Running full time needs large amounts of storage, transmission and flexible backup. That is why laws like SB 100 target “renewable and zero-carbon” power rather than renewables alone.
Have a question about this topic? Ask in the comments below. Our editors read every comment and answer questions here, and we add useful answers to the guide.
Sources
- eia.gov/energyexplained/electricity/electricity-in-the-us.php
- eia.gov/tools/faqs/faq.php
- gov.ca.gov/2025/07/14/in-historic-first-california-powered-by-two-t…
- energy.ca.gov/data-reports/clean-energy-serving-california
- leginfo.legislature.ca.gov/faces/billNavClient.xhtml
- seuc.senate.ca.gov/sites/seuc.senate.ca.gov/files/sb_1020_analysis.pdf
- lazard.com/research-insights/levelized-cost-of-energyplus-lcoeplus
- pv-magazine-usa.com/2026/07/13/u-s-solar-lcoe-on-the-rise-lazard-says
- irs.gov/newsroom/faqs-for-modification-of-sections-25c-25d-25e-3…