What Is Solar Energy, and How Does It Work?

Photo Credit:

You see solar panels everywhere: on rooftops, on car canopies, on compacting trashcans, on outdoor lamps, on spacecraft, and in solar farms like the one Altus Power owns and operates in Kapolei, HI. But what is solar energy, and how does solar energy work? How do those panels convert sunlight to electricity?

For starters, solar energy is a vast resource — even the most abundant energy resource on earth, according to the National Oceanic and Atmospheric Administration. In fact, the NOAA adds, the Sun provides 173,000 terawatts of solar energy to the Earth continuously, an amount more than 10,000 times the world’s total energy use. And that energy will be available for the lifetime of the Sun. “It's finite, but we're talking billions of years,” MIT physics professor Washington Taylor said in a 2011 MIT News article.
 

What is solar energy?

Solar energy involves the harnessing of heat and light from the Sun to generate warmth and electricity. Systems for harnessing solar energy be passive or active.  

Passive solar techniques include passive solar heating systems, which use the location, orientation, and construction materials of a building to control that building’s interior temperature, as the Environmental and Energy Study Institute explains.

Active solar techniques, meanwhile, include photovoltaic cells, concentrated solar power, and solar water heating. Photovoltaic cells use semiconductor material to convert sunlight into electricity. Concentrated solar power uses an array of mirrors to concentrate sunlight into receivers that convert the light into heat, which can then power turbines and generate electricity. And solar water heaters use solar collectors to heat water for households, commercial buildings, and swimming pools.

How does solar energy work?

Of the solar technologies listed above, photovoltaic (PV) cells might be the hardest to understand: How do those cells take in sunlight and put out electricity anyway?

As the U.S. Energy Information Administration explains, PV cells are made up of semiconductor material, typically silicon, that can absorb the photons — or particles of solar energy — of sunlight. When those photons are absorbed, electrons become dislodged — or “freed” — from the semiconductor material.

But in the case of silicon PV cells, there’s already an internal electric field, since a layer of n-type silicon is placed next to a layer p-type silicon, according to the American Chemistry Society. N-type silicon has an excess of electrons, while p-type silicon has an excess of holes. At the junction between the two layers, electrons fill in the holes, leaving negatively charged ions on one side and positively charged ions on the other.

Because of this electrical field, freed electrons are drawn to the n-side, while the holes they leave behind are drawn to the p-side. With an electrical imbalance between the two sides, conductors channel the electrons from the n-side, through a circuit that includes an external load like a battery, and back to the p-side, where the electrons fill in holes and the cycle begins anew.

What are the advantages of solar energy?

Though the creation of PV cells can be expensive and energy-intensive, solar energy use has definite advantages. The U.S. Energy Information Administration notes that the use of solar energy can have an indirect benefit to the environment by reducing or replacing more harmful energy sources.

For example, renewable energy like solar energy can reduce or replace energy derived from fossil fuels. An NREL study found that if the western United States got 35% of electricity from wind and solar, carbon emissions would drop by 25-45%, which is the equivalent of taking approximately 22 to 36 million cars off the road.

Solar energy can also “improve air quality, reduce water use from energy production, and provide ecosystem services for host communities through carbon sequestration, pollination, and ground and stormwater management,” according to the U.S. Department of Energy’s Office of Energy Efficiency & Renewable Energy.

In its 2011 book Solar Energy Perspectives, the International Energy Agency stated that the development of “affordable, inexhaustible, and clean” solar energy would have huge benefits. “It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise,” the agency contended. “These advantages are global.”

Keep your finger on the pulse

Subscribe to our newsletter to get the latest sustainability news and product updates from Altus Power.  

By subscribing you agree to with our Privacy Policy.
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

Photo Credit:

Community Solar

Refer a Friend to Altus Community Solar and You’ll Both Get $50

Are you already making a difference (and getting a discount on your annual electricity costs) through Altus Community Solar? Do you know someone who would want to do the same? You and they can both get $50 through Altus Power’s Community Solar referral program.

The Altus Power Team
July 15, 2024
2
min read

Photo Credit:

Community Solar

How Much Does It Cost to Switch to Solar? Zero, With Community Solar

The cost of solar panels can be a major outlay for homeowners, but there’s an alternative — one with which solar energy doesn’t have to cost a cent and can even save customers money. By participating in Community Solar, customers pay nothing up front, and they save money through utility bill discounts. Community solar is thus a viable option for households that can’t afford solar panels or — in the case of renters and condo owners — can’t install them. In fact, 77% of U.S. residential households are likely ineligible for rooftop solar systems, according to GTM.

The Altus Power Team
July 9, 2024
2
min read

Photo Credit:

Community Solar

U.S. Electric Bills Expected to Spike This Summer — Community Solar Can Help

Americans might get a shock when they see their electric bills this summer, as the cost to keep cool is projected to reach record-breaking levels in the United States in the upcoming months. Community Solar, though, offers savings, with no home equipment or upfront fees required.

The Altus Power Team
June 26, 2024
3
min read

Photo Credit:

Community Solar

Supporting Hawaii’s Renewable Revolution With Community Solar

Altus Power’s Hawaii program supports the state’s transition to clean electric power. As with our presence in other states, Altus offers Hawaii residents — homeowners and renters alike — the benefits of Community Solar, including the chance to reduce their community’s carbon footprint, without any equipment or changes to their existing utility.

The Altus Power Team
June 18, 2024
2
min read

Photo Credit:

Community Solar

Nearly 80% of U.S. Households Are Likely Ineligible for Rooftop Solar

Solar energy is on the rise, but what happens to the estimated 77% of U.S. households that can’t install rooftop solar? Whether they wish to save money or help reduce the United States’ reliance on fossil fuels, households for whom rooftop solar isn’t possible or affordable can still benefit from solar energy. Community Solar links households with solar projects — e.g. solar farms — by allowing them to purchase solar energy, often at a discount, that then gets delivered to the local grid.

The Altus Power Team
June 11, 2024
3
min read

Photo Credit:

Industry Analysis

The Story of Altus: The Founding of a Clean Power Company

Gregg Felton first experienced solar energy in grade school, when he and his classmates baked cookies in a solar oven during a field trip to Central Park. Now Felton is the CEO of Altus Power, the largest owner and operator of commercial-scale solar in the United States. We are proud to present Altus Power’s journey so far, introduce our team and partnerships, and provide you with Felton’s vision for Altus’s future.

The Altus Power Team
June 10, 2024
2
min read

Photo Credit:

Community Solar

The Environmental Benefits of Community Solar

June 5 is World Environment Day, an annual occurrence that the United Nations Environment Programme launched in 1973 to engage the public to protect and restore the Earth. And at Altus Power, we’re celebrating World Environment Day by spotlighting the environmental benefits of Community Solar, subscription-based clean energy programs that connect customers with solar energy projects around the United States.

The Altus Power Team
June 5, 2024
2
min read

Photo Credit:

Community Solar

Is Community Solar Available in My State?

If you’re wondering whether Community Solar is available in your state, you may already know that Community Solar fills in the gaps where residential solar isn’t available or affordable. Here are details on Community Solar policies in the states where Altus Power has Community Solar projects.

The Altus Power Team
May 20, 2024
4
min read

Photo Credit:

Community Solar

What Is a Solar Farm?

The term “solar farm” may conjure images of fields with rows of solar panels, much like rows of any agricultural crop. And that’s exactly what many solar farms look like. But these projects take other forms, too, especially in areas where land comes at a premium or where land isn’t suitable for other uses.

The Altus Power Team
May 16, 2024
4
min read

Photo Credit:

Community Solar

Powering New York State With Community Solar

The state of New York is committed to making solar energy accessible and affordable for all. We are proud to play a role in that progress as we continue expanding our Community Solar presence and serving customers in the Empire State.

The Altus Power Team
April 22, 2024
2
min read

Photo Credit:

Altus Power

Community Solar

What Is Community Solar?

If you’re curious about Community Solar, you’ve come to the right place. Here at Altus Power, we are leading the way towards a more sustainable future by offering Community Solar to homeowners and renters in multiple states across the country.

The Altus Power Team
January 29, 2024
3
min read

Photo Credit:

Industry Analysis

AI and Sustainability: 3 Lessons Learned From CES 2024

Now that CES 2024 is a few days behind me, I’ve had some time to reflect on everything I saw and heard during my trip to Las Vegas. Not only did I have the opportunity to experience the trade show floor and take in the wide range of sustainability innovations featured at the show, but I also had the honor of representing Altus Power on a panel about AI and sustainability alongside industry leaders: Rene Lammers from PepsiCo, Aviad Almagor from Trimble and moderator Ariana Stolarz from Accenture. Here are three themes that emerged from this lively conversation.

Julia Sears
January 22, 2024
4
min read

Photo Credit:

Community Solar

5 Ways to Cut Your Energy Costs in 2024

January 10th is National Cut Your Energy Costs Day and we're sharing our top 5 tips for saving on electricity costs this year.

The Altus Power Team
January 10, 2024
3
min read

Photo Credit:

Industry Analysis

The State of Clean Energy: A 2023 Recap and What’s Ahead for 2024

We're in a moment of huge growth in renewable energy. Check out our latest post for highlights from 2023 and a look ahead for 2024.

The Altus Power Team
January 5, 2024
4
min read

Photo Credit:

Unsplash

Altus IQ

Companies That Prioritize Decarbonization Are Winning the Game

Earlier this year, Forbes released a list of 100 "Net Zero Leaders" — companies like CBRE who are both "leading the transition to a low-carbon economy by 2050" and changing their business models to meet sustainability targets. Getting on a list like this — or striving to — isn't just about good PR. (Though that doesn't hurt either, of course.)

Julia Sears
December 5, 2023
3
min read

Photo Credit:

Pexels

Altus IQ

Spreading the Sunshine: How Solar Energy Is Empowering Commercial Companies to Transform Communities

In order for America to have a chance at hitting global climate targets, the commercial sector needs to ensure that its power is electric and clean. In short: the future of net zero depends on solar-forward commercial that transforms communities.

Lars Norell & Gregg Felton
December 5, 2023
3
min read

Photo Credit:

Altus

Community Solar

A Greener Future For NJ Starts With Community Solar: Here's What You Need to Know

After a successful two-year pilot program, the New Jersey Board of Public Utilities recently established a permanent Community Solar Energy Program designed to provide more New Jersey residents — especially from low- and moderate-income households — greater access to clean energy and significantly lower utility bills. The new program will support enough solar to enroll about 30,000 subscribers across the state. 

Altus Power Team
December 5, 2023
5
min read
View all