Top 30 Commercial Solar Contractors in 2026

Quanta Services installed more than 6.1 million kW of solar in 2025, making it the largest solar contractor in the country. But if you're a general contractor (GC) sourcing a rooftop array for a warehouse, school, or office park, Quanta isn't who you're calling. Once you strip out the utility-scale megaprojects, the commercial and industrial (C&I) solar leaderboard looks completely different, and it's topped by a division of a 100-year-old California construction company most people outside the industry have never heard of.

That company is Teichert Solar, and it's just one of dozens of contractors reshaping how commercial buildings get powered. Here's Siteline's breakdown of the top commercial solar contractors from Solar Power World's newly released 2026 rankings, based on kilowatts (kW) installed in 2025.

How Solar Power World Ranks Commercial Solar Contractors

Solar Power World (SPW) ranks contractors annually by the number of kW they installed in the prior year, and its list spans four markets: residential, commercial, utility, and community solar. A company's overall rank reflects total kW installed across the markets it serves, which is why utility-focused giants like Quanta Services, Moss, and McCarthy Building Companies dominate the top of the full 2026 list.

The commercial sublist works differently. It isolates each company's kW installed specifically in the commercial, industrial, and/or municipal markets, meaning a contractor's ranking here reflects work on office buildings, schools, warehouses, and government facilities—not solar farms. Some companies, like SOLV Energy, show enormous overall installation totals but rank lower on the commercial list because most of their work is utility-scale.

According to SPW's 2026 survey data, 64% of companies on this year's list serve the commercial market, which is more than any other segment, including residential (59%), utility (17%), and community solar (12%)—although these percentages overlap since many contractors work across multiple markets.

Top 30 Commercial Solar Contractors in 2026

Here's the full ranked list of the top 30 commercial solar contractors, based on C&I kW installed in 2025, according to Solar Power World's 2026 Top Commercial Solar Contractors list.

Source: Solar Power World, 2026 Top Commercial Solar Contractors. Figures reflect kilowatts installed in the commercial, industrial, and municipal markets in 2025.

5 Commercial Solar Contractors to Watch in 2026

A few names on this list stand out, either because they're the largest players or because they're growing fast enough to reshape the competitive landscape.

1. Teichert Solar

Headquarters: Sacramento, California

Teichert Solar is a division of Teichert Construction, one of California's oldest civil infrastructure firms. Teichert Solar became its own division in 2018 and has since installed more than 650 megawatts (MW) of solar capacity, specializing in solar carports, garage tops, ground-mount systems, and single-axis trackers.

2. DCE Services

Headquarters: Cornelius, North Carolina

DCE Services is the installation arm of DCE Solar, which has operated since 2019 and installed more than 2 gigawatts (GW) of solar capacity nationwide. DCE Services focuses on rooftop installations, handling everything from racking and modules to electrical work and system startup.

3. Solar Landscape

Headquarters: New Jersey

Founded in 2012, Solar Landscape bills itself as the nation's most experienced commercial rooftop and community solar developer. The company has installed more than 250 commercial rooftop projects totaling over 40 million square feet, and it built 82% of all New Jersey rooftop solar projects energized in 2025.

4. MARS Energy Group

Headquarters: Rocklin, California

Founded in 2021, MARS Energy Group consolidated several specialized divisions, including NewGen Energy and Unified Renewables, under one brand in 2024. In November 2025, the company acquired Nelnet Renewable Energy, adding engineering, procurement, and construction (EPC) capacity and an active commercial solar pipeline.

5. M Bar C Construction

Headquarters: San Marcos, California

M Bar C Construction has specialized in solar and non-solar carports for commercial, industrial, and municipal clients since 1997 and has installed more than 1 GW of solar support structures nationwide. In January 2026, M Bar C acquired AFC Solar, a Texas-based carport contractor that appeared on Siteline's original 2024 commercial solar list, a reminder of how quickly this market is consolidating.

What the C&I Solar Boom Means for Subcontractor Billing

Commercial solar contractors are growing fast, and growth brings the same billing headaches every commercial subcontractor eventually runs into. As firms like MARS Energy Group and M Bar C Construction expand through acquisitions, they're taking on more crews, GC relationships, and pay apps to track, often before their back-office processes catch up.

Once a solar contractor is running dozens of active commercial projects across different GCs and portals, spreadsheets stop being enough. Missed billing deadlines and unresolved compliance holds cause payment delays and eat into cash flow.

A few things solar subcontractors scaling their commercial work should have in place:

• A consistent process for generating and submitting pay apps across every GC portal they work with.
• A system for collecting lien waivers and other compliance docs from lower-tier vendors and subcontractors, especially on larger EPC projects with multiple trade partners.
• Visibility into which GCs pay fastest before bidding new work, since payment speed varies widely by GC.

Solar contractors who treat billing as an afterthought tend to hit the same wall other fast-growing subs hit: strong project pipeline, weak cash flow. Siteline's billing software helps subcontractors of every trade—including solar—get paid faster by automating pay apps, lien waivers, and collections in one place. Book a demo now to learn more.

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FAQ

What counts as commercial solar versus residential or utility solar?

Commercial solar refers to systems installed on business and industrial properties, such as office buildings, warehouses, and distribution facilities. It differs from residential solar (homes) and utility-scale solar (large solar farms that feed directly into the power grid).

Which company installed the most commercial solar in 2025?

According to Solar Power World's 2026 rankings, Teichert Solar installed the most commercial solar in 2025, with 114,430 kW across the C&I market.

How is Solar Power World's commercial ranking different from its overall ranking?

The overall ranking reflects total kW installed across all markets a company serves, including utility-scale work. The commercial sublist isolates kW installed specifically in the commercial, industrial, and municipal markets, which is why the two rankings feature almost entirely different companies at the top.

How big is the commercial solar market in 2026?

Solar Power World's 2026 survey found that 64% of companies on its Top Solar Contractors list serve the commercial market.

Do commercial solar contractors need construction billing software?

Yes. Commercial solar contractors bill through the same GC portals, face the same lien waiver requirements, and deal with the same payment delays as any other commercial subcontractor. As solar EPCs and installers scale through acquisitions and new GC relationships, manual billing processes tend to break down quickly.

Where can I see the full 2026 Top Solar Contractors list?

The complete list, including residential, utility, and community solar rankings, is available on Solar Power World's website.

How often does Solar Power World update this list?

Solar Power World publishes an updated Top Solar Contractors list annually, typically in July, based on installation data from the prior calendar year.