How CRE Sponsors Finance Solar: The Five Capital Structures

Most sponsors approach solar the wrong way round. They start with a proposal from an installer, look at the payback period, and try to decide whether the project is worth doing. The payback number is the least interesting part of the decision. A solar array on a commercial asset is a capital-structure question: you are adding a long-lived, cash-generating improvement to a property that already has a lender, a hold period, an equity waterfall, and a tax profile. Those four constraints determine which financing structures are even available to you, and that is what decides whether the project happens.

This piece walks the five structures that actually get used on commercial real estate, what each one does to your balance sheet and your returns, and the diligence question that kills more of these deals than economics ever do.

First: the four constraints that pick the structure

Before comparing structures, get honest answers to four questions. Each one eliminates options.

1. 01How long are you holding? A structure that amortises over 20 years behaves very differently in a five-year hold than in a permanent hold. Some structures transfer cleanly to a buyer; others become a negotiation item at sale that costs you basis points on the exit cap.
2. 02Can you use the tax credits? Federal energy credits are only worth face value to a taxpayer with enough tax liability to absorb them. Many real estate partnerships — particularly those with significant depreciation shelter or foreign or tax-exempt LPs — cannot. If you cannot use the credit efficiently, you either monetise it or you let someone else own the system.
3. 03What do your loan documents say? This is the question sponsors skip and then discover eight weeks in. Most senior loans restrict additional liens, additional indebtedness, material alterations, and the granting of easements or rooftop rights. Every one of those is implicated by a solar project.
4. 04Who wants the electricity? On-site consumption by a single tenant, on-site consumption by common-area load, net metering back to the utility, and export to a community-solar subscriber base are four different revenue models with four different risk profiles.

Structure one: cash from the balance sheet

The simplest option and the one most sponsors reject too quickly. You fund the system from equity or from a capital-improvement reserve, you own the asset, and you keep every dollar of energy saving and every tax attribute. There is no lender consent needed for an unencumbered payment, no new lien, no third-party counterparty, and nothing to explain to a buyer at exit beyond a functioning improvement that reduces operating expense.

The objection is always the same: it is the most expensive capital in the stack, and using it here means not using it somewhere else. That objection is legitimate but it should be tested rather than assumed. If the system reduces a controllable operating expense on an asset you intend to hold, the saving capitalises into value at your exit cap rate. A dollar of permanent NOI improvement at a 6% cap is worth roughly sixteen dollars of value. Run that comparison against your actual marginal use of equity before dismissing cash.

Structure two: C-PACE

Commercial Property Assessed Clean Energy is the structure that has changed the most in the last three years, and it is now the default first look for energy improvements on commercial assets in enabling jurisdictions. C-PACE is long-dated, fixed-rate, fully amortising capital repaid through a voluntary assessment on the property tax bill. Because repayment travels with the property rather than the borrower, terms run far longer than a commercial mortgage — often twenty to thirty years — and the obligation transfers to a buyer at sale rather than needing to be retired.

More than twenty-five states plus the District of Columbia have enabling legislation, and volumes have grown from a niche efficiency product into mainstream commercial real estate finance. Cumulative investment passed roughly $10 billion by the end of 2024, and the product is now being used at institutional scale — a single $465 million C-PACE origination closed in January 2026 to support a 532-unit office-to-residential conversion in Washington, D.C.

What C-PACE funds varies by programme but generally covers energy efficiency, renewable generation, water conservation, and in a growing number of states seismic and resiliency work. Retroactive funding — reimbursing eligible costs already incurred, typically within a lookback window — is available in some programmes and is one of the more useful features for sponsors who have already completed work with expensive capital.

Structure three: equipment loan or capital lease

A straightforward secured loan or lease against the equipment itself, usually from a specialty finance provider. Shorter than C-PACE, generally seven to fifteen years, and secured by the system rather than the real property. The advantage over C-PACE is that it does not touch your property tax bill and, depending on structure, may avoid the senior-lien consent problem — though most loan documents still capture it as additional indebtedness requiring consent.

The trade-off is term and transferability. A fifteen-year amortisation against a five-year hold means you are either prepaying at exit or asking a buyer to assume equipment debt on a system they did not choose. Read the prepayment terms carefully; some of these facilities carry make-whole provisions that materially change the economics of an early sale.

Structure four: third-party ownership via PPA or site lease

You do not finance the system at all. A developer finances, owns, and operates it, and you either buy the electricity under a power purchase agreement at an agreed rate, or you lease them roof or ground rights and collect rent. Your capital contribution is zero. Your tax attributes are also zero — the developer takes them, which is precisely why the structure exists.

This is the correct answer for a large share of real estate partnerships, because it converts a capital-intensive project with a tax-credit dependency into either a reduced operating expense or a new revenue line. It is particularly clean where the sponsor cannot use the credits and does not want the operating responsibility for a generating asset.

The cost is control and exit flexibility. A twenty-year PPA is an encumbrance a buyer will diligence. If the contract rate is above market at the time of sale, it is a value deduction. If the agreement has weak assignment provisions, poor removal or relocation terms, or an inadequate performance guarantee, it becomes a genuine problem in a disposition. Negotiate the exit provisions of a PPA as carefully as the price.

Structure five: tax-equity and credit-transfer structures

For projects large enough to justify the transaction cost, the tax attributes can be monetised directly. Historically this meant a tax-equity partnership, where an investor with tax appetite takes an ownership interest structured to allocate the credits and accelerated depreciation to them. Since the Inflation Reduction Act, there is a simpler path: a direct transfer of the credit for cash under Section 6418, which survived the 2025 tax legislation intact.

A transfer converts a credit you cannot use into cash you can put into the capital stack at closing. It is not free — credits sell at a discount to face value, and the buyer will require indemnities, insurance, and diligence on the underlying project — but it is dramatically less complex than a tax-equity partnership and it has opened credit monetisation to project sizes that could never previously support it.

The diligence item that kills these projects

It is almost never the energy model. It is the existing loan documents. Solar projects on encumbered commercial real estate touch several standard covenants at once: restrictions on additional liens, restrictions on additional indebtedness, requirements for lender approval of material alterations, limits on granting easements or licences over the property, and insurance and casualty provisions that assume a roof without a generating asset bolted to it.

Sequence the work accordingly. Pull the loan agreement, the deed of trust or mortgage, and any intercreditor or subordination agreements before you commission a feasibility study. Identify every consent you need and who has to give it. On a securitised loan, understand whether you are dealing with a servicer, a special servicer, or a rating-agency confirmation requirement, because each has a different timeline. Doing this first turns a project that dies quietly at week eight into a project with a realistic schedule.

Where a capital advisor is actually useful here

Solar on real estate sits in an awkward gap. Energy developers understand the generation asset but not the real estate capital stack. Real estate lenders understand the stack but treat the generation asset as an unfamiliar risk. The work that makes these projects close is translation: presenting the improvement in terms a real estate credit committee underwrites, and structuring the capital so the incentive value actually reaches the deal rather than being lost to a structure the sponsor could not use.

If you are weighing an energy project on an asset you own, the useful first conversation is about the constraints — hold period, tax position, and loan documents — not about the array.