What are the environmental benefits of solar energy–and what are its impacts?

Solar energy is a win-win: It saves you money and contributes to a cleaner environment. Solar panels draw their energy from the sun, a renewable resource that never diminishes. When you install a solar energy system at your home or business, you reduce your reliance on fossil fuels, improving your air quality and protecting the environment. We'll explain the key environmental benefits of solar energy and some of its lesser-known impacts.

For the average homeowner, powering 100% of your home with solar energy is equivalent to removing the emissions created by driving 19,316 miles per year in a typical car—a tremendous environmental benefit. 

About 60% of the electricity that power plants generate in the U.S. comes from fossil fuels like coal and natural gas—but extracting and burning fossil fuels is expensive and causes global warming and climate change. Even if we somehow ignored those problems, we'd eventually run out of fossil fuels. 

By contrast, solar energy creates clean, renewable power from the sun, so it's free, abundant, and doesn't create any carbon emissions or local air pollution. Unlike other renewable power sources like wind and hydropower, it's relatively easy to install on small patches of private property like your roof. If we could capture all of the sun's energy shining on the Earth for just one hour, we could power the entire world for one year!

By investing in solar energy, you can help reduce our reliance on nonrenewable fossil fuels in favor of one of the most abundant, consistent sources of energy available: our sun. Here are the two main ways solar panels benefit your local environment:

1. Solar energy decreases greenhouse gas emissions

Generating electricity with solar power instead of fossil fuels can dramatically reduce greenhouse gas emissions, including carbon dioxide (CO2). When we burn fossil fuels, we emit greenhouse gasses, leading to global warming and climate change. Climate change already contributes to severe environmental and public health issues, including extreme weather events, rising sea levels, and ecosystem changes.

Going solar will shrink your carbon footprint because you'll create fewer greenhouse gas emissions (including carbon dioxide and methane). One home installing a solar energy system can have a measurable effect on the environment: According to the U.S. Energy Information Administration, the average U.S. household uses 10,632 kilowatt-hours (kWh) of electricity annually. Switching that amount of electricity generation from fossil fuels to solar power has the same emissions reduction effect as planting 125 trees every year or eliminating the annual production of 8,440 pounds of coal.

2. Solar energy reduces respiratory and cardiovascular health issues

One of the most significant solar energy benefits is that it doesn't release air pollutants because it's a clean energy source. An analysis by the U.S. Department of Energy (DOE) 's National Renewable Energy Laboratory (NREL) found that widespread solar adoption would significantly reduce nitrous oxides, sulfur dioxide, and particulate matter emissions, all of which can cause health problems. NREL found that, among other health benefits, solar power results in fewer chronic bronchitis, respiratory and cardiovascular problems, and lost workdays related to health issues.

Solar panels don't produce emissions once they're mounted on your roof. But they aren't zero-emissions resources for their entire lifetime: They have to be manufactured in a factory first and recycled at the end of their useful life, and these two processes do have some environmental impact.

Many researchers frame the environmental impact of solar energy with the concept of energy payback time (EPBT). The EPBT tells us how long it will take for solar panels to produce enough clean electricity to "pay back" the energy required to produce them. This calculation varies depending on a few different factors, including:

• The productivity of your solar panels: If you live in a sunny area and your solar panels are very efficient, your system will generate more electricity and have a shorter EPBT.

• The solar panel manufacturing process: Some solar panels require more energy for production than others. For example, thin-film modules have a smaller carbon footprint than silicon modules because they need less energy for manufacturing.

• The manufacturing location of your solar panels: Solar panels must be transported from their place of manufacture to their installation location. If your solar panels were manufactured in Europe or Asia and installed in the U.S., they'd have a higher EPBT than those manufactured in the U.S. due to transportation-related emissions.

While the EPBT of a solar panel depends on many factors, the market is moving in the right direction: According to an analysis from Fraunhofer-Gesellschaft, a large European research organization, between 1996 and 2020, the average energy payback time for rooftop monocrystalline silicon solar panels declined by 12.8%. In the U.S., the EPBT of silicon rooftop solar panels with 19.9% efficiency was just 0.95 years in 2020—much shorter than a solar panel's expected 25-40 year lifespan. 

As the solar industry matures, manufacturers are constantly looking for ways to move to domestic manufacturing and improve the efficiency of the solar panel manufacturing process and solar cells themselves, which means that solar's EPBT will continue to decrease.

For example, the same report from Fraunhofer-Gesellschaft found that the amount of material used for silicon cells dropped 84% over the past 16 years, and the average efficiency of solar cells in commercial panels increased by 33% in the past ten years. This means panels require less silicon, and installations require fewer panels to meet the same production, lowering EPBT. And as more solar panels reach the end of their life cycles, recycling them will also become more cost-effective and efficient.

How does solar photovoltaic energy differ from solar thermal energy?

Solar panels on your roof convert solar energy into usable electricity via the photovoltaic effect. The photovoltaic effect is a property of materials in solar cells called semiconductors that enable them to generate an electric current when exposed to sunlight. We can also produce heat for your home or electricity for large-scale solar installations by directly capturing the heat from solar radiation and using it as solar thermal energy. 

How has solar technology changed?

Solar panels are more efficient, produce more power, and require less silicon for manufacturing than they did just ten or even five years ago. Today, SunPower offers the most efficient solar panels installed in residential systems at 22.8% efficiency. However, researchers achieved 47% solar cell efficiency in 2020 in a lab setting. 

Can you go off-grid with solar?

It is possible to go off-grid with solar if you pair your panels with a battery. However, installing a battery system big enough to provide complete energy independence will likely cost a lot of money, depending on your energy use. You'll usually see the best financial savings by remaining connected to the grid. If you want protection from grid outages, installing a battery that can support your critical power loads for a few hours to a day rather than one that will power your entire home is best.

While the environmental impact of solar energy is greater than zero, its overall benefits far outweigh its costs: With a solar installation, you can save money on your electric bills while reducing your carbon footprint and improving your air quality. To go solar with confidence, check out the EnergySage Marketplace. You'll receive multiple solar quotes from vetted installers to compare them based on factors like installer reputation, equipment quality, and price, enabling you to find the right system at a great price.