What is the difference between a physical and a virtual PPA?

A physical PPA delivers actual electricity from the generator to the buyer, either on-site or through the grid. A virtual PPA (also called a synthetic or financial PPA) is a purely financial contract: the buyer never takes delivery of the power but settles the difference between a fixed contract price and the market price, and takes the renewable energy certificates. Corporations use virtual PPAs to hit sustainability targets without changing where their electricity physically comes from.

How long does a power purchase agreement last?

Utility-scale and corporate PPAs typically run 10 to 20 years, because the generator needs a long revenue horizon to finance the project. On-site commercial solar PPAs are often 15 to 25 years. Shorter terms exist but usually carry higher per-kilowatt-hour prices, since the developer has less time to recover its capital.

Who owns the renewable energy certificates in a PPA?

It depends on what the contract says, which is why the REC ownership clause matters. If the buyer is signing the PPA to meet a clean-energy goal, the buyer needs to retain the RECs. If the developer keeps them or sells them separately, the buyer is paying for electricity but cannot legally claim the environmental benefit. Spell this out explicitly.

What happens if the project produces less power than promised?

A well-drafted PPA includes a performance guarantee or an expected output figure, plus a remedy if the generator underperforms, such as a shortfall payment or a price adjustment. Without one, the buyer bears the risk of a bad solar year or an underbuilt project. Buyers should also confirm whether force majeure covers weather variability or only extraordinary events.

Do I need a PPA if I am just buying solar panels for my building?

No. If you buy and own the system outright, you do not need a PPA because you own the electricity it produces. A PPA is used when a third party owns the equipment and sells you the power it generates, which is common when a business wants solar without the upfront capital cost. In that case a separate installation contract governs the build and the PPA governs the ongoing sale of electricity.

Power Purchase Agreement Template (PPA)

Learn how to write a power purchase agreement (PPA): physical vs. virtual PPAs, pricing, key clauses, term length, and common drafting mistakes.

A power purchase agreement (PPA) is the contract at the center of almost every solar, wind, and clean-energy deal. It sets the price a buyer pays for electricity, how long the arrangement lasts, who carries the risk when a project underperforms, and who gets to claim the renewable energy. Get it right and you lock in predictable energy costs for a decade or more. Get it wrong and you can end up paying for power you cannot use or clean-energy claims you do not legally own.

This guide explains what a PPA is, the main types, how the pricing works, and how to draft one clause by clause, along with the mistakes that most often derail these deals.

What Is a Power Purchase Agreement?

A power purchase agreement is a long-term contract in which a power producer (the seller or generator) agrees to sell electricity to a buyer (the offtaker) at an agreed price. The seller builds, owns, and operates the generating asset, usually a solar array or wind farm. The buyer commits to purchasing the output, or the financial equivalent of it, over a fixed term.

Both sides get something out of it. The generator gets a guaranteed buyer, which is what makes a project financeable in the first place. Banks rarely fund a solar farm on the hope that someone will buy the power later; they want a signed PPA that proves the revenue is contracted. The buyer locks in a price that is usually below grid rates and steadier than them, and, when the contract is written for it, gets to count the electricity toward a sustainability goal.

PPAs range from a single rooftop system powering one building to a 200-megawatt wind farm feeding a Fortune 500 company's operations across several states. The core structure is the same; the complexity scales with the size of the deal.

Types of Power Purchase Agreements

Not every PPA delivers electricity the same way, and the type you choose changes almost every other term in the contract.

On-Site (Behind-the-Meter) PPA

The generator sits on the buyer's property, most often solar panels on a roof or a carport. The electricity flows directly to the building without touching the public grid. The buyer pays for what the system produces, and a third-party developer owns and maintains the equipment.

This is the common structure for a business that wants solar without the capital outlay. The developer handles financing, installation, and upkeep; the building owner simply buys the power. If you are going this route, the physical build is usually governed by a separate solar panel installation contract, while the PPA governs the ongoing sale of electricity once the system is live.

Off-Site (Physical) PPA

The generating asset is located elsewhere and delivers power to the buyer through the grid. A utility or a grid operator moves the electricity, and the buyer takes actual delivery at its meter. These deals are larger, and they involve a third party: the transmission provider. Off-site PPAs often require a sleeving arrangement, where a utility acts as an intermediary to schedule and balance the power.

Virtual (Synthetic or Financial) PPA

No electricity changes hands directly between the parties. Instead, the generator sells its power into the wholesale market, and the buyer settles a financial difference: if the market price is below the agreed strike price, the buyer pays the shortfall; if it is above, the generator pays the buyer. The buyer keeps its normal utility supply and takes the renewable energy certificates (RECs) so it can claim the clean-energy benefit.

Large corporations favor virtual PPAs because they can support a wind farm in Texas while their offices sit in New York, all without rewiring anything. The trade-off is exposure to market price swings, which is why the strike price and settlement mechanics deserve careful drafting.

How PPA Pricing Works

Price is the clause everyone negotiates hardest. A handful of standard structures show up in most deals.

Fixed price. A single per-kilowatt-hour rate for the entire term. Simple and predictable, which buyers like, though it can look expensive if grid prices fall.
Escalator. A fixed starting rate that rises by a set percentage each year, commonly 1 to 3 percent. This gives the developer rising revenue and still tends to stay below projected grid inflation.
Discount to grid. The buyer pays a set percentage below the local utility rate. Attractive on paper, but it removes price certainty because the bill tracks whatever the utility charges.
Indexed price. The rate floats against a market index. Rare in corporate PPAs because it defeats the purpose of locking in stability.

Whichever structure you use, define the price in plain numbers with a worked example. A rate table that a reader has to reverse-engineer is a dispute waiting to happen.

Key Clauses in a Power Purchase Agreement

1. The Parties and the Facility

Name the seller and buyer with full legal entity names and states of formation. Then describe the facility precisely: location, technology, nameplate capacity in megawatts, and the point of delivery where responsibility passes from seller to buyer. Vague facility descriptions cause fights when a project is built slightly smaller than promised.

2. Term and Commercial Operation Date

State the length of the agreement and, critically, when the clock starts. Most PPAs run from the commercial operation date (COD), the day the project is fully built and generating at scale, not the signing date. Include a long-stop date: if the project is not operational by then, the buyer can walk away. This protects a buyer from being tied to a project that never gets built.

3. Price and Payment Terms

Beyond the pricing structure above, spell out the billing cycle, the metering method, invoice timing, and what happens on late payment. Specify which meter's reading governs and who reads it. For virtual PPAs, describe the settlement calculation step by step, including the reference market and the settlement period.

4. Delivery, Metering, and Title

Define where the electricity is delivered and the exact moment title and risk of loss transfer from seller to buyer. Identify the revenue-grade meter that measures output, who owns it, and how disputes over readings are resolved. In an off-site deal, address transmission losses and who pays for them.

5. Renewable Energy Certificates

Decide who owns the RECs and say so explicitly. This is the single most common source of confusion in green PPAs. A buyer signing the contract to meet a carbon goal must retain the RECs; otherwise it is buying electrons but not the right to call them clean. The mechanics of transferring or retiring the certificates should be described, not assumed.

6. Performance Guarantees

A generator's output varies with weather, equipment health, and design. A buyer wants some floor. Include an expected annual output figure and a remedy if the project falls short, such as a shortfall payment or a rate credit. Conversely, some PPAs cap how much power the buyer must take, so a sunny year does not blow past the buyer's needs.

7. Change in Law and Change in Tax Credits

Incentives drive the economics of most energy projects. If a tax credit disappears or a new grid fee shows up, the numbers shift. A change-in-law clause allocates that risk: it says who absorbs the cost and whether the price can be renegotiated. Given how often energy policy moves, do not skip this.

8. Curtailment

Sometimes the grid operator orders a project to stop feeding power in, or the buyer cannot take it. The curtailment clause defines who is responsible when generation is cut and whether the buyer still pays for power it did not receive. Buyers should watch for "deemed delivered" language that bills them for curtailed energy.

9. Credit Support and Security

Because these contracts run for a decade or more, each side wants assurance the other can perform. This often means a parent guarantee, a letter of credit, or a security deposit. The larger and longer the deal, the more this clause matters. If you are new to this concept, the same idea appears in commodity deals; an offtake agreement uses nearly identical credit-support mechanics to protect a long-term buyer.

10. Default, Termination, and Buyout

Define what counts as a default for each party, the cure periods, and the remedies. Many PPAs also include a buyout schedule, letting the buyer purchase the system outright at set points during the term. State the termination payment so neither side is surprised.

11. Force Majeure and Governing Law

Cover events outside either party's control and, importantly, clarify whether ordinary weather variation counts (it usually should not, since intermittency is the whole nature of renewables). Then name the governing state law and dispute forum.

How to Write a PPA: Step by Step

Step 1: Fix the structure first. Decide whether the deal is on-site, off-site physical, or virtual. Everything downstream, pricing, delivery, RECs, depends on this choice.

Step 2: Identify the parties and the facility. Use full legal names and pin down the project's capacity, location, and delivery point.

Step 3: Set the term and the start date. Tie the term to the commercial operation date and add a long-stop date that lets the buyer exit if construction stalls.

Step 4: Choose and define the price. Pick fixed, escalating, or discount-to-grid, then write the rate in numbers with a worked example.

Step 5: Assign the RECs. State plainly who keeps the certificates and how they transfer.

Step 6: Allocate the risks. Address performance shortfalls, curtailment, change in law, and force majeure. These clauses are where a generic template usually falls short.

Step 7: Add credit support and remedies. Specify the security each party posts and the consequences of default.

Step 8: Finalize governing law and signatures. Confirm each signatory has authority to bind their entity, then execute.

Common Mistakes to Avoid

Leaving REC ownership silent. If the contract does not say who owns the certificates, a buyer chasing a sustainability target may find it has no legal claim to one. This is the mistake that most often undercuts the entire point of a green PPA.

Starting the term at signing instead of COD. A project can take a year or more to build. Tie the term to operation, and add a long-stop date so a delayed project does not trap the buyer.

Ignoring curtailment economics. "Deemed delivered" language can leave a buyer paying for power that never arrived. Read this clause closely.

Copying a residential template for a commercial deal. A rooftop lease for a homeowner and a corporate offtake contract share a name and almost nothing else. The scale, credit terms, and risk allocation are different animals. For a plain services arrangement, a general service agreement is a better starting point than a mismatched PPA.

Skipping the change-in-law clause. Energy incentives move constantly. A PPA without a mechanism to handle a lost tax credit or a new fee leaves both sides exposed. If the project sits on leased ground, coordinate the PPA with the underlying solar land lease so the two contracts do not contradict each other on term or termination.

When to Use a PPA

A business wants solar without buying the equipment. A developer owns the system and sells you the power.
A company needs to hit a clean-energy target but cannot physically source renewable power where it operates. A virtual PPA solves this.
A utility or large buyer is financing a new project and needs a contracted revenue stream to make the financing work.
A landowner or facility host is hosting generation and wants the electricity at a fixed, predictable rate for years.

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Generate Your Power Purchase Agreement with Contractable

A power purchase agreement rewards precision. The pricing, the term start, the REC ownership, and the risk clauses all have to line up, and a mismatched template can cost far more than it saves. Contractable builds a power purchase agreement tailored to your deal, with the right structure, pricing terms, and risk allocation for your situation. No lawyers or legal background required.