Compare a green-power offer in two parts: what you pay for electricity or a subscription, and what renewable attributes you receive. Ask who owns and retires the renewable energy certificates, what quantity and period they cover, and how those commitments appear in the contract.
This guide concerns U.S. purchasing arrangements. Availability, tariffs and consumer protections depend on location. Gather a year of electricity use, your current rate and the full terms of each offer before comparing prices.
Identify the arrangement being sold
EPA’s green-power supply options distinguishes standardized products from customized project arrangements. Start by identifying whether the offer changes your electricity supplier, adds a premium to existing service, creates a solar subscription or supplies certificates separately.
On a narrow screen, scroll the table sideways. Keyboard users can focus the table region and use the arrow keys.
| Arrangement | Compare the financial terms | Confirm the renewable claim |
|---|---|---|
| Utility green-power program | Premium, quantity covered and cancellation rules | How certificates are acquired and retired for customers. |
| Competitive supplier offer | Full supply price, variable terms, fees and renewal | Resource mix, covered consumption and certificate evidence. |
| Community solar subscription | Subscription charges, bill credits, allocation and exit terms | Who retains the project’s renewable attributes. |
| Unbundled certificates | Price per MWh, quantity, period and verification | Retirement for the named customer without double counting. |
A bill-credit arrangement can save money while assigning renewable attributes elsewhere. Treat a project’s location, your financial participation and your right to make a renewable-use claim as separate fields to verify. For an on-site power purchase agreement, EPA explains that the contract specifies attribute ownership.
Read the certificate evidence
A renewable energy certificate, or REC, represents the non-power attributes associated with one MWh of qualifying renewable generation. On a shared grid, certificates provide the accounting trail for renewable-electricity use; they do not identify a dedicated physical stream of electrons to a particular customer.
Request the generation period, resource and location, covered quantity, tracking identifier and retirement evidence. Retirement removes a certificate from further trading for the stated claim. Check that the supplier retires the attributes on your behalf and identifies the period and beneficiary clearly.
EPA’s tracking-system explanation describes the role of registries and third-party verification in avoiding duplicate ownership. Ask which system or verification process is used and retain its report with the contract.
Different objectives need different evidence. Annual renewable-use matching, generation near your region, hour-by-hour matching and helping finance a new project are distinct goals. Ask how the offered product addresses the goal you actually have. A generic renewable percentage alone cannot answer all four questions.
Put prices on the same basis
Fictional household comparison: annual use is 9,000 kWh, equal to 9 MWh. Offer A adds a $0.02/kWh green premium covering all consumption: 9,000 × $0.02 = $180 per year.
Offer B supplies 9 MWh of certificates at $12/MWh plus a $15 annual fee: 9 × $12 + $15 = $123 per year. Both examples assume matching quantities and periods and documented retirement. They leave the household’s underlying electricity cost unchanged.
The $57 difference compares the attribute premiums only. Different resource, geographic, timing or project-development commitments could justify different prices. Confirm those terms before treating the offers as equivalent.
If an offer changes the electricity supply rate, calculate its full annual supply cost, fixed fees and likely variable-rate exposure against the current contract. For community solar, model subscription payments and actual bill-credit rules month by month. Avoid combining a credit with an assumed discount unless the contract supports both.
Keep a reviewable purchasing record
Record the offer date, provider, tariff or contract, usage estimate, renewal price mechanism, cancellation cost and credit/refund treatment. Request written answers to missing fields before signing. After the first billing period, reconcile the charges and covered quantity; after the reporting period, retain the promised certificate evidence.
Use precise claims that match the record: specify the quantity, period and type of renewable purchase. EPA’s market principles help distinguish renewable-energy attributes from carbon offsets and other environmental objectives.
For owning a rooftop system, see solar quote and savings comparisons. For a system-level explanation of electricity delivery, see the transmission grid guide. A clear contract and evidence trail make a purchasing decision easier to check at renewal.
Green-power offer comparison
Green-power offer comparison — plain-text download. Save a copy and fill it in with your own information. The file includes instructions, assumptions and references so it can be used independently.