What Is My Old Commercial Solar System Worth?

An older commercial solar system is worth whatever income it will earn from here on, minus what it will cost to keep running and the risks a new owner takes on. That is why there is no single price per panel, and why you can get a first ballpark with only the size, age and location.

A letter or an email arrives asking about the solar on your building. Before you dig through old contracts or try to remember the login for a monitoring portal you haven't opened in years, you want to know one thing: is this even worth my time? That's a fair question. It's the one owners ask us most often, usually before they share a single document, and often in almost these words: "Based on the age of the system, what's it worth?"

This guide is for owners of commercial solar systems that are six or more years old, mostly in New Jersey and nearby states, and for the property managers, brokers, lenders, attorneys and finance advisors who work with them. If you'd rather start with a quick figure, our instant solar estimate needs no paperwork.

Why Isn't There a Simple Price per Panel?

Because a buyer pays for what the system will earn, not for the hardware, and two identical systems can earn very different amounts.

Used panels taken off a roof are worth little on their own. The value sits in the working system: the contract to sell its power, the state certificates it earns, the right to stay on the roof or land, and its approved connection to the grid.

Picture the same panels on two buildings. One sells its power at a good rate for eight more years. The other has two years left on its contract and pays roof rent that eats most of its income. That's why rules of thumb based on size alone tend to mislead.

What Income Does a Buyer Look At?

Three things: who pays for the power and at what rate, how many years of state incentive payments are left, and how much the system produces today.

• ●Power sales or bill savings. Many older systems sell their electricity to the building under a PPA (power purchase agreement), a contract where the building buys the system's power at a set price for a set number of years. The rate and the years left on that contract matter most. If instead the system is net metered (it offsets the building's own electric bill), its value is the bill savings, which rise as utility rates rise.
• ●SREC or TREC years left. In New Jersey, a system earns one certificate for every 1,000 kilowatt-hours it makes, and those certificates are sold separately from the power. SREC stands for Solar Renewable Energy Certificate; TREC is the Transition Renewable Energy Certificate that followed it. Most legacy SREC systems earn for 15 years (10 years if they registered after October 29, 2018), and TREC systems earn for 15 years. The clock starts when your utility gave permission to operate, and a sale does not reset it. A system in year 6 of its certificate term is in a very different spot from one in year 14. Our New Jersey guide explains which program you are likely on.
• ●Production today. What it makes now, not in year one. Some decline is normal: a review of nearly 2,000 field measurements by the National Renewable Energy Laboratory found panels lose a median of about 0.5% of their output per year (Jordan and Kurtz, 2012). Bigger drops usually point to a fixable problem. Here's how to tell if your system is still performing.

What Costs Pull the Value Down?

Anything the next owner will have to pay for: repairs, inverter replacement, insurance, roof or land rent, monitoring and routine upkeep.

• ●Repairs that are already due. Offline inverters, damaged panels or a dead revenue meter (the meter that counts what the system produces) all come off the value, along with the lost production. Our guide to reading a commercial solar repair quote helps you size them.
• ●Inverter replacement. Inverters, the boxes that convert the panels' power into the kind your building uses, usually wear out long before the panels. A buyer plans for that cost even if yours are running fine today. [DAVID TO CONFIRM: DGE allows for future inverter replacement when it values a system, even if the inverters are working today.] It's not a small risk: an NREL report describes a 924-kilowatt carport system that sat down for two years because the money to replace a failed inverter wasn't set aside (Walker et al., 2020).
• ●Site lease or roof rent. If the system pays rent to the building or landowner, that rent comes straight out of its income. One owner asked us whether an array was worth dealing with at all, because its rent schedule was higher than what it earned each year.
• ●Insurance, monitoring and upkeep. Costs that run every year.
• ●End-of-contract duties. Some PPAs require the system owner to remove the panels and restore the roof at its own cost when the contract ends. That future bill is part of the math.

Why Do Contracts and Paperwork Change the Number?

Because a buyer has to step into every contract, and anything unclear is a risk the buyer has to allow for.

Is it clear who owns the system? Can the PPA and the site lease be assigned (handed over to a new owner) without a fight? Is there still a loan on it, such as a PSE&G Solar Loan, which has to be paid off or taken over at sale? Is the certificate account in PJM-GATS (the regional system where New Jersey certificates are tracked) in your name?

Gaps don't kill a sale. They usually just widen the range until they're filled. Our questions to ask about a commercial solar contract cover what to look for, and selling a solar system without the paperwork explains how missing pieces get rebuilt.

What Happens to the Value After Year 15?

Nobody knows exactly, which is why owners and buyers often see "year 16" differently.

Many New Jersey systems reach the end of their PPA and their SREC term at about the same time. After that, the panels keep working and net metering does not end with the SRECs. But certificate income drops: once the incentive term ends, the system can still earn a general renewable certificate (a Class I REC), which usually sells for much less than an SREC. A PPA may also end with the system handed to the building owner or removed.

Owners and their advisors sometimes argue that power and certificate prices will be higher by then. A buyer also has to weigh older equipment that costs more to keep running and prices nobody can promise. A reasonable approach is to value the contracted years with care and treat the years after as a set of possible outcomes, not a single bet. [DAVID TO CONFIRM: DGE values the years under contract and incentive first and treats income after the PPA and SRECs end as a range of scenarios rather than a single forecast.]

Is a Broken System Worth Anything?

Yes. A system that isn't running is worth less than one that is, but it still has value.

With a working system, a buyer can count on income from day one. With a broken one, the buyer subtracts the repair cost and the time it takes to get running again. But the panels, the racking, the approved grid connection, the roof or land rights and any remaining certificate years are all hard and slow to recreate from scratch. Often the fix is an inverter or a wiring repair, not a new system. Do Good Energy buys systems as-is, including ones that need work. [DAVID TO CONFIRM: DGE will make offers on systems that are not producing today, with the repair cost reflected in the price.]

What Do I Need to Get a First Number?

Very little: the system size, the year it started operating and the location. A few answers and documents then narrow the range.

For a first ballpark, a buyer needs:

• ●System size in kilowatts
• ●The year it started operating
• ●ZIP code
• ●Whether you own it outright or a third party does, who buys the power, and whether it's working

What tightens the number:

• ●The PPA and site lease
• ●12 to 24 months of production data (a monitoring export or utility bills)
• ●The SREC or TREC registration and GATS account details
• ●The utility's permission to operate letter
• ●Repair and maintenance records, and any loan papers

Our document checklists list what matters for rooftop, carport and ground-mount systems. [DAVID TO CONFIRM: DGE gives a range from size, age and location first, then narrows it to a firm offer as contracts and production data come in.] The final price depends on the system's condition, contracts and records. When we buy, we take over every contract and responsibility that comes with the system and keep it running.

Start With a Ballpark Estimate

You don't need a full file to find out whether selling is worth a conversation. Our instant solar estimate asks a few quick questions about your system and gives you a starting range in about 23 seconds, with no obligation.