What is Solar Energy? What is Solar Energy? What is Solar Energy?

What is Solar Energy?

What is Solar Energy? What is Solar Energy?

What is Solar Energy?

Everything you need to know about solar energy.

When we say solar energy, we’re talking about capturing the sun’s light (photons) and converting it to electricity (voltage) through a process called “the photovoltaic effect,” or PV. Solar energy that’s captured using PV technology can power everything from homes, businesses, cars and aircraft to small appliances like calculators, portable power stations and more.

The sun is the single most abundant energy source in our solar system. Without it, we’d be just another cold rock floating through space. But exactly how powerful is the sun? According to the U.S. National Renewable Energy Laboratories (NREL), the amount of energy from sunlight that hits the Earth in one hour could supply the world’s energy needs for an entire year! That’s pretty powerful.

"As of 2020, the United States has a total installed solar capacity of 97.7 gigawatts (GW). That’s enough to power nearly 17.7 million homes!*"

Solar energy has been one of the fastest-growing sources of new energy in the world for many years now. As of 2020, the United States has a total installed solar capacity of 97.7 gigawatts (GW). That’s enough to power nearly 17.7 million homes!* And thanks to improved technology, more affordable materials and increased customer demand, solar continues to become more affordable. For many homeowners, that means rooftop solar now makes economic sense and can provide long-term savings.

Watch this quick 2-minute video about how biomass energy works:

Make a commitment to using clean, renewable energy in your own life with a solar energy plan from Green Mountain Energy.

Is solar energy renewable or nonrenewable?

Renewable energy is defined as energy that comes from a source that can naturally replenish itself on a human timescale. Suffice to say, the sun won’t be going away for a long, long, long time. And as long as the sun shines, we can use it to heat, cool and light our homes and businesses without polluting our precious planet with carbon dioxide (CO2) emissions.

How does solar energy work?

When the sun shines onto a solar panel, energy from the sunlight is absorbed by PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field within the cell, causing electricity to flow.

That’s the science behind solar energy. Now for a little history.

Though humans have used solar energy to light fires and keep their homes warm since the dawn of time, we only began to understand how solar energy works in 1839, when French physicist Alexandre-Edmond Becquerel discovered the photovoltaic effect that converts sunlight into electricity. Forty-four years later, American inventor Charles Fritts developed the world’s first rooftop solar array, using selenium coating on panels to produce an electric current. But it was Albert Einstein, in 1905, who helped us understand exactly how light produces the energy that we can capture to generate electricity. The paper that Einstein wrote completely changed the way we look at light. It also won him a Nobel Prize, which we hear is pretty awesome.

Modern PV technology was pioneered in the 1950s and 1960s, when the U.S. government developed it for use in our space program. Vanguard I, the first spacecraft to utilize solar panels, was launched in 1958, and PV solar panels have been an important part of satellites and other spacefaring vehicles ever since.

How does a solar panel work?

The modern solar panel generates electricity in much the same way that Fritts’s solar array did back in the 19th century, only now we capture solar energy using silicon solar cells that are much more efficient and can produce a lot more electricity. However, in order to use that electricity to power our lives, we have to convert it from direct current (DC) power to alternating current (AC) power. To do this, the solar panel is attached to a device called an inverter, which changes the electricity from DC to AC. From there, 100% clean electricity – generated by solar energy – is sent off for use in homes, businesses and more.

How we use solar energy today.

When multiple solar panels are wired together, they form what’s called a solar array. The more panels you have, the more electricity you’ll generate. And depending on how big your array is, the solar energy that you capture has three applications: utility, commercial, and residential.

Utility solar farms

Utility-scale solar power plants supply the national electric grid with large amounts of electricity for use in homes and businesses across the country. Today, the typical solar energy plant generates as much electricity as the average small- to medium-sized coal and fossil fuel plant. However, as PV technology gets better and less expensive, future solar power plants are expected to generate electricity in line with our nation’s biggest power plants.

Commercial Solar

Commercial solar arrays are smaller than the utility-size plants. They’re usually installed by commercial property owners on vacant land, rooftops and parking structures in order to provide electricity to the businesses that occupy their buildings. Depending on weather conditions and the size of the commercial solar installation, the business may even generate more solar energy than they need on a given day, which they can sell back to the local utility.

Residential solar

Thinking about installing your very own solar array right on your rooftop? If you do, you’ll be joining the more than 2 million homes in the U.S. that generate residential solar power. Residential rooftop solar systems generate power for individual homes. Just like utility and commercial solar arrays, they’re connected to the grid and can sell back the electricity they don’t use. Since homeowners typically supplement their solar power generation with traditional electricity to meet their energy needs, during the night or on cloudy days, the electricity they send back to the grid is usually exchanged for bill credits. And now that it’s getting less expensive to install, residential solar is becoming more and more popular as a renewable energy option.

How much does solar energy cost?

Though it’s different from state to state and from commercial to residential uses, the cost of solar energy keeps going down for a few reasons. First, as the technology gets better, the materials used to make solar arrays are getting less expensive. At the same time, consumer demand is increasing due to more people learning about the benefits of solar energy for the planet.

Governments at every level are seeing these trends, too, and they’re investing in solar energy by offering tax incentives and rebates for homes and businesses that go solar. For example, the federal solar tax credit, also known as the investment tax credit (ITC), can reduce the cost of a commercial or residential solar energy system by 30%.

For people who don’t want to install a solar system, utility-scale solar farms can provide 100% clean, renewable solar energy to any home or business using renewable energy certificates (RECs).

What are the benefits of solar energy?

Solar energy produces zero greenhouse gases. On top of that, it doesn’t require vast amounts of water like fossil fuels do. Conserving water and keeping the air clean? That’s a win-win for us all.

We’ve said it before, and we’ll say it again: improved technology, lower hardware costs and the demand for sustainable energy have steadily driven down the cost of solar panel systems in recent years.

The future shines bright for solar. The U.S. Bureau of Labor Statistics has rated solar energy as one of the fastest-growing job markets in America, with employment of solar PV installers projected to grow 51% from 2019 to 2029.

Homes and businesses with rooftop solar installations often see reduced electricity bills. Plus, whatever they don’t use can be sent back to the electric grid in exchange for payments or bill credits through various programs.

Unlike oil and natural gas, the nation’s solar supply won’t be running out anytime soon. As a country, we can generate solar power on our own soil without worrying about rising commodity prices, international political relations or other global factors.

Good for business

Leading with sustainability sets a positive tone for businesses. According to a 2017 Cone Communications CSR Study, 89% of customers are likely to switch to a company associated with a good cause (such as operating with 100% renewable energy) given similar price and quality. 


We can’t say it enough: as long as the sun shines, we’ll have access to solar energy. Each individual has the power to help increase the demand for renewable energy generation in America.

Choose a solar energy plan with Green Mountain Energy.

When you choose a 100% solar energy plan with us, you can help build a cleaner and greener future for your community and the planet. We have several solar energy plans that can meet your electricity needs without installing a single solar panel, plus green tools and add-ons that help you reduce your carbon footprint even further. And if you want to install a rooftop solar system on your home, we can help you do that, too.

We make it simple to choose 100% clean electricity made from renewable sources like solar energy. Let’s build a cleaner, greener tomorrow together.

This page is for general educational purposes only. Green Mountain Energy product offerings do not include all of the renewable sources shown.

*U.S. Department of Energy

Explore more renewable energy sources:

Wind energy

Harnessing the natural power of wind to make electricity for everyone.

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Geothermal energy

Using the heat generated beneath the Earth’s surface to power our lives.

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Harnessing the energy of flowing rivers, oceans and waterfalls.

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Biomass energy

Releasing and reusing the energy stored in waste and organic matter.

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Our customers have avoided


pounds of CO2

That’s like planting


new trees.