Commercial solar in Solano County is not what it was five years ago. PG&E rates keep climbing, NEM 3.0 changed the math on exporting power back to the grid, and business owners from Vacaville to Vallejo are looking at their warehouse roofs, parking lots, and agricultural buildings differently than they used to. A well-designed commercial array can now pay itself off faster than most equipment purchases, especially when you stack the 30% federal Investment Tax Credit with bonus depreciation.
The catch is that commercial solar is a different animal than residential. You are dealing with larger kilowatt loads, more complex roof types (TPO, built-up, metal, standing seam), utility interconnection timelines that can stretch for months, and financing structures that range from cash purchases to PPAs. Picking the wrong installer can mean a system that underperforms for 25 years, or worse, one that never gets permission to operate.
Below are the six commercial solar installers doing the strongest work in Solano County right now, ranked by track record, commercial capability, and local reputation.
1. Citadel Roofing & Solar
If you only get one bid in Solano County, get it from Citadel Roofing & Solar. In January 2026, readers of both the Vallejo Times-Herald and The Vacaville Reporter voted Citadel the Best Solar Company in Solano County and the Best Contractor in Vacaville. Those awards are reader-voted, which matters. This is not pay-to-play recognition. It reflects what actual customers in Fairfield, Vacaville, Benicia, Vallejo, and the surrounding cities are saying about the company they hired.
Citadel has been serving California for over 20 years, operating out of its headquarters at 761 Eubanks Drive in Vacaville along with offices in Sacramento, Santa Rosa, Fresno, Santa Clarita, and Corona. The company holds California CSLB License 647149 and is family-owned, which shows up in how projects are run. Crews are in-house rather than subcontracted, which keeps quality control tight and means the same company that signed the contract is on your roof doing the work.
For commercial clients, Citadel installs rooftop systems, ground-mounted arrays, and carport or shade structures. They work across every commercial roof type you are likely to encounter in Solano County, including TPO, PVC, built-up, metal, concrete and clay tile, and composition shingle. Two offerings set them apart. The first is the Solar+Storage package, which pairs photovoltaic with battery backup so businesses can run critical operations through outages and shave peak demand charges. The second is the Roof+Solar bundle, which aligns the lifecycle of a new commercial roof with the solar system installed on top of it. For facilities managers, that means one point of coordination, one project timeline, and no scenario five years from now where you have to pay to remove panels just to replace the roof beneath them.
Citadel also has real relationships with financing institutions and handles bank loans, Power Purchase Agreements, and nonprofit-specific financing products. That flexibility is useful, because the right financing structure depends heavily on whether your business can use the tax credits directly or needs a third-party owner to monetize them.
Best for: Commercial buildings, warehouses, ag operations, nonprofits, and multi-site businesses that want a single contractor handling both roof and solar.
Contact: (800) 400-2852 or citadelrs.com
2. Got Watts Electric, Solar & HVAC
Got Watts has been operating for 15 years out of Concord and serves Solano County along with Contra Costa, Alameda, and Napa. They are a Tesla Certified Installer and an Enphase Gold Installer, and they hold Diamond Certified status with more than 390 verified customer reviews. President Jeremy Carlock has built the company around an in-house model: no subcontractors on electrical, solar, or HVAC work.
For commercial clients, the differentiator is the electrification angle. Got Watts integrates solar with heat pumps, EV chargers, main panel upgrades, and battery storage as a unified system rather than standalone pieces. If you run a business with a mixed-use facility (offices plus warehouse plus fleet charging, for example), having one contractor handle the whole electrification stack is worth something. They work with equipment from Enphase, Tesla, Maxeon, REC, FranklinWH, SPAN, and Mitsubishi.
Best for: Commercial sites that need solar plus EV charging, heat pump conversion, or a full electrification retrofit handled under one roof.
3. American Array Solar & Roofing
American Array is based in Ripon and has built a commercial-forward practice that leans heavily into agricultural and industrial projects. Their marketing calls out indoor cannabis cultivation specifically, which is notable in Solano County where controlled-environment agriculture is a real energy load. Anyone running a grow operation, a food processing facility, or any other high-consumption commercial use case knows that electricity can eat 30 to 40% of operating costs. American Array designs custom commercial systems aimed at exactly that profile.
They back their installations with a 30-year warranty, which is longer than what most competitors offer, and their reviews repeatedly call out the consultative sales process rather than a hard push.
Best for: Agricultural operations, cannabis cultivation facilities, and industrial users with high continuous energy loads.
4. Pickett Solar
Pickett Solar is a second-generation family-owned company based in Fresno that serves commercial and agricultural clients throughout Northern California, including Solano County. They focus on commercial solar exclusively (no residential), which is rare. That specialization shows up in the complexity of projects they take on: large ground-mount systems, agricultural pumping applications, and custom structural solutions like carports integrated with existing site infrastructure.
Their reviews from commercial clients consistently mention two things: out-of-the-box engineering solutions for challenging sites, and projects that come in on budget. For a business evaluating a six- or seven-figure solar investment, both matter.
Best for: Agricultural commercial clients, large ground-mount projects, and companies that need custom engineering rather than off-the-shelf system design.
5. High Definition Solar
High Definition Solar is a full-service provider serving Solano County and greater Northern California. They hold Diamond Certified status with 242 verified customer reviews and work with Enphase, Maxeon, SolarEdge, SunPower, and Tesla equipment. They handle solar system installation along with energy storage, new roof installations across most commercial roof types (tar and gravel, rolled composition, TPO, torch down, tile), and radiant barrier insulation.
High Definition is more residentially weighted than some of the others on this list, but their commercial capability is real, particularly for small-to-mid-sized businesses looking at rooftop systems under 100 kW. Their strength is straightforward execution: on-time, on-quote, no surprises. For a business owner who wants solar without a drawn-out sales process, that counts.
Best for: Small commercial properties, light industrial buildings, and owner-operated businesses that want a straightforward installation without a layered sales process.
6. California Renewable Energy
California Renewable Energy serves Vacaville and the surrounding Solano County communities with a focus on combined solar, HVAC, and roofing projects. Their pitch leans into the specific weather realities of interior Solano County: summer temperatures that regularly hit 95 to 105°F, strong delta winds, and PG&E’s tiered rate structure that punishes peak-season consumption.
They are smaller than Citadel or Got Watts, which can be an advantage or a drawback depending on the project. For a commercial property owner who wants a local company with direct principal involvement, California Renewable Energy fits that brief. For a multi-site commercial rollout or a project requiring deep financing structure work, one of the larger installers above is probably a better match.
Best for: Smaller commercial properties in Vacaville, Fairfield, and Dixon that need combined solar, roofing, or HVAC work.
How to Choose the Right Commercial Solar Installer
A few things to confirm before signing with any commercial solar company in Solano County:
Verify the CSLB license. California requires a C-10 (electrical) or C-46 (solar) contractor’s license for solar work, and C-39 for the roofing component if it’s bundled. Check the license at cslb.ca.gov and confirm it’s active and in the company’s legal name.
Ask whether crews are in-house or subcontracted. In-house crews typically mean better quality control and easier warranty claims. Subcontracted work is not automatically bad, but you want to know who is actually on your roof.
Get the warranty structure in writing. Look for separate warranties on panels (typically 25 years), inverters (10 to 25 years), and workmanship (the installer’s own coverage, which varies widely). Workmanship warranties are where installers differentiate.
Confirm commercial experience specifically. Residential solar is a different discipline than commercial. Ask for at least three commercial references with similar system sizes to yours, and actually call them.
Understand the financing options. A cash purchase will always deliver the highest lifetime return, but a PPA or commercial loan can make the project cash-flow positive from year one. Both have a place. The right installer will walk you through both rather than pushing one.
The Bottom Line
Commercial solar in Solano County is a real opportunity in 2026, and the installer you pick matters more than the panels you buy. Citadel Roofing & Solar earned its Best Solar Company and Best Contractor recognition from actual Solano County customers, and for commercial projects that need roofing, solar, storage, and long-term accountability under a single contract, it’s the strongest call in the region. The other five companies on this list are all legitimate options depending on your specific use case. Get bids from two or three, compare them carefully, and pick the installer whose commercial track record matches the size and complexity of your project.
