The Solar Energy Companies You Need to Know About

Solar energy companies are businesses that manufacture, install, or design solar collection and conversion equipment used to make electricity from sunshine. Solar power companies range from large to small.

Following is a list of the top 15 largest and best solar companies in the US, compiled by Green Technology Media. Short annotations of each company are included, compiled by

According to The Solar Energy Industries Association (SEIA) “The solar market is humming on its way to unprecedented growth” and SEIA expects “the total market size for solar in the United States to more than double within the next five years.”

In the US, the largest three solar companies “helped to deploy nearly a quarter of the commercial solar market in 2017,” (Davis).

Solar energy companies on Green Technology Media’s (GTM’s) recently published “who’s who” of commercial solar list are divided by how they function in the solar energy supply chain. Companies are then ranked by the company’s commercial solar capacity in megawatts (MW).

Thanks to Green Technology Media for the image.

Sunpower, the top-ranking US solar company develops and manufactures solar equipment, while Tesla owns and develops of solar energy technology. Other solar companies may own assets, develop technologies, arrange financing, or produce solar energy. Energy producers are called electricity production companies (EPCs).

Since the commercial solar industry is fragmented—some companies install, others manufacture, still others provide electricity, and some do both—it is difficult to say exactly how many companies there are in the US. But, Wikipedia has other more enlightening numbers:

As of the end of 2017, the United States had over 50 gigawatts (GW)                   of installed photovoltaic capacity. [1] In the twelve months through                   February 2018, utility scale and distributed solar power generated                       55.6 terawatt-hours (TWh), 1.37% of total U.S. electricity. During                       the same time period total solar generation, including estimated                         distributed solar photovoltaic generation, was 80.6 TWh, 1.98% of                     total U.S. electricity.

GTM notes that for companies like Telsa, which owns about 90% of its commercial projects, “having more control over multiple steps in the value chain appears to be a winning strategy.” Tesla sold 24% more solar installations in 2017 despite constrictions in the market caused by tariffs.

Tesla’s Gigafactory 2 in Buffalo, New York has finally begun installations of its solar roof for non-employees.

Tesla, which has recently bought Solarcity, is probably the most recognized name in solar technology, and is expected to have “1 gigawatt of annual capacity by the end of 2019, and 2 gigawatts at some point in the future” (Pyper).

According to Fred Lambert writing for electrek, Tesla also has plans to open an electric semi-truck factory that will eventually produce 10,000 trucks per year. Rumors place the manufacture of the trucks at Tesla’s Gigafactory 1 in Nevada, US. If Tesla succeeds in producing 10,000 trucks per year, it will be out-producing all other manufacturers.

Tesla has 500 advanced orders for the new semi, including an order for 100 trucks for Pepsico and another 125 for UPS.

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Sunpower, clearly the top-ranking solar company on GTM’s who’s who list, is a developer and module manufacturer. Because Sunpower both directly installs commercial solar energy systems and has channel partners, it was able to make gains last year even while the market constricted.

Sunpower focuses on solar installation projects larger than 1 MW while its channel partners target medium and small projects (less than 1 MW). Sunpower may not have the joie de vivre of an Elon Musk at its helm, but it’s still doing just fine.

NRG, third on the list, is an asset owner and developer. NRG Inc. is an energy company that, according to its website, brings “years of experience and a data-driven mindset to help you get the most out of your energy.”

NRG is committed to sustainable energy sources and specializes in new technology applications and “diverse generation sources” (  NRG hopes to achieve a 50% reduction in carbon emissions by 2030 and a 90% reduction by 2050.

NRG is the leading integrated power company in the US, serving 3 million customers.

NextEra Energy is also a solar energy owner and developer. According to its website, NextEra energy, “is a Fortune 200 energy company with about 45,900 megawatts of generating capacity, revenues of over $17 billion, and about 14,000 employees throughout the United States and Canada.” And lucky those employees are since NextEra Energy made one of Forbes’ America’s Best Employers for the third year in a row (

Geronimo Energy ranks fifth on the list and is a solar energy developer with headquarters in Minneapolis and numerous projects in Minnesota, North Dakota, South Dakota, Illinois, New York and Michigan. Geronimo, “provides custom renewable energy solutions for utilities and corporations looking to harness renewable energy for business growth” and estimates that it has 1800 MW of renewable energy projects both operational and in construction and “a multi-gigawatt development pipeline of wind and solar projects in various stages of development throughout the United States.”

Geronimo prides itself on being farmer-friendly. Its mission statement: “We seek to leave the world a better place than it was before we touched it: environmentally, through the deployment of clean and renewable energy; in our communities, through economic development; for our employees, through personal improvement and pride in what we do; for our shareholders, through profitable operations” (Geronimo).

The rest of the story is here below the chart.

Rank Company Value Chain Participation MW Capacity
6 Borrego Developer and EPC 68.4
7 WGL Asset Owner 45.4
8 Wunder Capital Financier 37.3
9 Greenskies Asset Owner and Developer 34.7
10 REC Solar Developer and EPC 34.3
11 Nexamp Developer and Asset Owner 33.7
12 Coldwell Solar EPC 32.8
13 SoCore Energy Asset Owner and Developer 32.5
14 EnterSolar Developer and EPC 29.7
15 Ameresco Asset Owner and Developer 27.1

Click here to download the complete list.

Borrego, in business since 1980, is a utility scale solar energy developer and Energy Production Company (EPC). Borrego offers a “complete suite of services to commercial solar and energy storage customers including: development; Engineering, Procurement, and Construction (EPC); Operations and Maintenance (O&M); and, commercial solar financing” (Borrego).

Borrego has built a portfolio of more than 1,100 projects totaling more than 400 MW of solar capacity. The company likes to work on projects with educational facilities, government agencies, corporations, water districts, real estate developers, independent power producers (IPPs) and investor-owned utilities (IOUs). Borrego prides itself on being able to engineer solutions across an array of energy problems.

WGL is an asset owner that does environmentally friendly residential, commercial, industrial, and government installations. WGL has been busy.

According to its website, WGL plans to create a national legacy of renewable energy solutions. To this end, WGL has invested over 100 million a year for the past 4 years and now has over 700 million in clean energy projects in 28 states.

WGL uses “a distributed generation model that involves large multiple-solution projects that employ natural gas, solar, remotely generated wind and other solutions,” which could include onsite generation systems (WGL). It is currently creating such an energy model for the US General Services.

Thanks to WGL for the graphic.Another example of WGL’s work is the IND Solar Farm, a solar farm developed for Indianapolis Power and Light (IPL) on 183 acres located on the Indianapolis International Airport (IND).

The project is the largest solar farm on an airport in the world. WGL operates Phase IIA of the project which is currently generating 19.7 million kilowatt hours annually, equivalent to powering 1,586 homes for one year. The farm has 87,488 solar panels supplying power to the grid that serves the airport and the community. When completed, the farm is expected to generate more than 36.1 million kilowatt hours of solar energy annually, enough to power 3,650 homes. WGL emphasizes that the project is good for the whole community, both economically and environmentally: “The IND Solar Farm also provided jobs for over 100 local laborers and is generating clean, emissions-free energy that helps improve air quality in the skies over the airport and in the region” (WGL).

Next is Wunder Capital, founded in 2013 and based out of Boulder, Colorado. Wunder is the only company in the top 10 listed as only a financier of solar energy. Don’t let that fool you, though. Wunder Capital accurately claims to “make investing in solar dead simple” and will let you start your clean energy portfolio for only a $1,000.00 minimum investment.

You invest your dollars, and Wunder Capital finds the best clean energy projects to invest your money in. At a 6-7% estimated return on your investment, it is dead simple. Wunder also boasts having the, “best online investment portal,” and we must say, it is a simple, streamlined portal, user friendly and easy to navigate.

According to Wunder Capital’s website, “Wunder actively manages everything, from the sourcing of commercial solar opportunities, to the underwriting, contracting, and construction of each project. Once a system is live, Wunder manages the ongoing operation and maintenance of the array, bills the energy customer, and distributes proceeds to investors.”

Greenskies belongs to the Clean Focus Group, which includes Greenskies, Clean Focus Yield, and Clean Focus China. The group “originates, develops, finances, constructs, owns, and operates renewable energy projects in the United States, Taiwan, and China.”

Thanks to Greenskies for the graphic.Like the other companies on the list, Greenskies is determined to make clean energy opportunities available and affordable. Unlike the others on the list, Greenskies is the only “end-to-end solar provider that owns the entire value chain.” It literally owns every step in the process of creating energy from sunlight.

Greenskies believes it can provide solar energy more affordably and efficiently because of its vertical integration. It also likes long term partnerships with investors and other clients, and to this end, Greenskies customers can “Work with a single person for your entire project, from origination to operations – all under one roof” (

REC Solar is listed as a developer and energy production company. It was founded in 1997. REC is a subsidiary of Duke Energy.

Nexamp is a solar energy developer and asset owner with “more than 200 solar systems completed totaling over 100 megawatts of solar generating capacity.” Nexamp “develops, designs, builds, owns, finances, and operates commercial-scale solar systems.” It is also a mission-oriented company that provides community solar projects, which offer individuals the opportunity to go solar without equipment.

If you click here, you can “solarize” your electric bill. Here is how it works. Nexamp builds a community solar farm. Customers like you purchase a share in the solar farm and are then entitled to a share of solar energy which is received from the existing utility grid. Once a month, Nexamp pays customers their share directly onto their electric bill. Nexamp has two new community solar projects on its website, on in Massachusetts and one in New York state, with many more still in the pipe.

Thanks to Nexamp for the graphic.

Coldwell Solar, an energy production company, proudly proclaims itself, “California’s leading solar company.” Ranking twelfth on the list, this mission-driven company is family owned. Coldwell was founded in 1986. Its owners have a combined 100 years of solar energy experience.

The company’s focus is on commercial, industrial, and government solar projects. Coldwell offers consulting, financing, design, engineering, and construction help as well as solar check-ups and performance monitoring.

Right now, according to Coldwell’s website, “the commercial solar market is expected to triple by 2020. Commercial, government and nonprofit building owners with large rooftops and parking lots, and farms and agricultural businesses with plenty of open space are monetizing these assets with solar energy. . . providing an immediate boost to the bottom line.”

SoCore Energy is a developer and asset owner serving large companies, electric cooperatives, municipalities, and other power suppliers. SoCore also provides community solar opportunities for some customers.

EnterSolar is a developer and asset owner that started out in New York state and has since become a national solar energy player. EnterSolar is a mission-driven company that works at “creating a trusted, single source for corporations looking to advance towards clean energy.” EnterSolar credits its success to its commitment to sustainability and clean energy.

Thanks to Entersolar for the photo.

Ameresco is an asset owner and developer which has been in business since 2000. Ameresco helps customers complete Energy Savings Performance Contracts (ESPCs) projects. ESPC’s are designed to allow federal agencies to make energy efficiency upgrades and facility improvements without special appropriations from Congress. An ESPC might also be between an energy company and a public or private organization. The company’s website explains that by “Leveraging budget neutral solutions, including energy savings performance contracts (ESPCs) and power purchase agreements (PPAs), we eliminate the financial barriers that traditionally hamper energy efficiency and renewable energy projects.”

First Solar, America’s leading manufacturer of solar panels, along with Tesla vis a vis SolarCity, were the two companies not impacted by the new tariffs. First Solar does manufacture some of its panels offshore, but the technology used is different and exempt from the tariffs (Deagan). Investment experts are raving about First Solar’s future, noting that it outperformed consensus estimates in the first quarter of 2018.

First Solar also recently announced that it will open a new solar manufacturing plant near its existing facility in Perrysburg, Ohio. According to Pyper, “The 1.2-gigawatt factory will produce the company’s Series 6 thin-film PV modules, with construction slated to begin in mid-2018 and full production mode expected in late 2019.”

In conclusion, it is blatantly obvious that now is a great time to be in solar energy or to get into solar energy. Top to bottom level jobs are going unfilled. More jobs are coming. Businesses, municipalities, and homeowners can install solar energy systems with any of a long list of qualified providers and see almost immediate returns on investment (ROI’s) in the form of lower electricity bills. More solar system installations enable more distribution of the grid, meaning more locations producing solar energy onsite. Just about everybody agrees making our grids stronger also makes our communities, and by extension our nations, more self-reliant.

We aren’t even going to start on how much money the average family can save with solar panels. Here is a short list of residential solar installers, JFYI. Here is a link to a longer list. Enough said.

Sunrun is one of the largest solar companies in the US, installing solar panel systems in 22 states. Sunrun has been in business since 2007. Sunrun has recently gotten into the energy storage market. Sunrun offers leases, power purchase agreements (PPA’s), and offers loans to help you pay for your solar energy system.

Vivint Solar started out doing business as Vivint Home Security, but in 2011 it became Vivint Solar. Serving over 100,000 customers in 21 states, Vivint originally installed solar panels free, often with a PPA-like program. Like Sunrun, Vivint now offers $0 down plans, PPAs, full ownership models, and has a solar loan program.

Sunova has its headquarters in Houston, but also does business in 21 states and U.S. territories. Sunnova doesn’t have in-house installation or maintenance workers. Rather Sunova partners with local installers. Fortunately, Sunnova’s solar energy packages are on $0 down terms and include options to either own the system or lease it.

SunPower produces some of the most recommended solar panels. They also only partner with local installers, giving them authorization to sell and install SunPower products. SunPower plans to expand into community solar soon.

Although SolarCity has recently decreased its residential installation and maintenance, it is still one of the larger US solar companies. Founded by Elon Musk’s famous cousins (Tesla) in 2006, SolarCity currently serves 27 states and was just acquired by Tesla in 2016. What’s hot and interesting right now about SolarCity is that it is producing its recently upgraded solar roof in a huge factory in Buffalo, New York, called Gigafactory 2.

SolarCity, Sunrun, and Vivint supplied 56% of residential solar in 2017, primarily leasing solar arrays to customers. However, this year the number is likely to decrease to 50% because smaller companies like Sunworks and Petersen Dean are offering loans to finance purchasing solar systems outright (Sweet).


Suggested Resources

Visit the NREL, EIA, SEIA, and Solar Technologies Office websites for more solar energy resources.

Works Cited

Davis, Michelle. “” 22 March 2018. Webpage. 1 May 2018.

Deagan, Brian. “” 23 January 2018. Webpage. 10 May 2018.

“” 25 April 2018. Webpage. 1 May 2018.

“” 2018. Webpage. 10 May 2018.

“” 7 May 2018. Webpage. 9 May 2018.

“” 2017. Webpage. 1 May 2018.

Lacey, Stephen. “” 31 May 2016. Webpage. 8 May 2018.

Lambert, Fred. “” 8 February 2018. Webpage. 9 May 2018.

Piper, Julia. “” 26 April 2018. Webpage. 1 May 2018.

Solar Energy Industries Association. “U.S. Solar Market Insight Report 2017 Year-In-Review.”. March 2018. ebook. 11 May 2018.

Sweet, Cassandra. “” 30 May 2016. Webpage. 8 May 2018.

Thanks to GTM for the featured image.