title: "Renewable Energy Certificates (RECs) Explained" description: What RECs are, how they work, and what it actually means when your utility or employer claims to use 100% renewable energy. summary: What RECs are, how they work, and what it actually means when your utility or employer claims to use 100% renewable energy. category: policy difficulty: Intermediate updated: 2026-02-10 tags: ["RECs", "renewable energy", "policy", "green power", "carbon"] relatedTools: ["/tools/emissions-estimator"] faqs:
- question: Does buying RECs directly reduce emissions? answer: It's debated. Purchasing RECs provides revenue to renewable generators and creates a market signal favoring clean energy. However, most environmental economists agree that the emissions impact depends on whether your REC purchase causes additional renewable generation to be built (additionality). Purchasing RECs from an already-built wind farm that would operate regardless has minimal direct impact. Voluntary RECs bundled with a PPA for new construction have stronger additionality claims.
- question: How much does a REC cost? answer: Voluntary (unbundled) REC prices vary widely. National wind RECs trade for as low as $1–$5 per MWh. Solar RECs (SRECs) in states with solar carve-outs can sell for $20–$300+ per MWh depending on the state and supply/demand balance. Compliance REC prices in states with aggressive RPS mandates can be higher.
- question: If I have rooftop solar, do I own RECs? answer: Yes — as the system owner, you automatically own the RECs associated with your solar generation. If you sell your RECs (or your utility's net metering agreement includes REC transfer), you can no longer claim the renewable attributes of that electricity. Read your interconnection agreement carefully.
- question: Are RECs a form of greenwashing? answer: They can be, depending on how they're used. A company buying cheap, unbundled wind RECs to claim "100% renewable" while doing nothing else to reduce emissions is making a weaker environmental commitment than one signing a PPA for new solar construction. The distinction between "matched with RECs" and "directly powered by renewables" is important for consumers to understand.
Renewable Energy Certificates (RECs)
When a wind turbine or solar farm generates 1 megawatt-hour (MWh) of electricity, two things are created: the physical electricity (electrons flowing into the grid) and a Renewable Energy Certificate — a tradeable certificate representing the environmental attributes of that generation.
RECs are the accounting system that prevents double-counting of renewable energy claims and enables renewable energy markets.
How RECs Work
The Two-Product Model
Renewable generators produce:
- Electricity — sold on the wholesale market like any other electricity
- RECs — sold separately (unbundled) or together with the electricity (bundled)
The REC represents the "greenness" — the environmental, social, and other non-power attributes. Whoever retires (uses) the REC gets to claim the renewable energy.
Tracking Systems
RECs are tracked through regional registries:
- PJM-GATS (Mid-Atlantic)
- NEPOOL GIS (New England)
- M-RETS (Midwest)
- WREGIS (West)
- NC-RETS (Carolinas)
Each REC has a unique serial number, generator ID, fuel type, vintage (month/year of generation), and location. This prevents the same MWh from being claimed twice.
Types of REC Markets
Compliance Markets (Mandatory)
Most states have a Renewable Portfolio Standard (RPS) requiring utilities to obtain a percentage of their electricity from renewables. As of 2025:
- 30+ states have an RPS or equivalent
- Standards range from 10% to 100% renewable by various target dates
- Utilities buy RECs to demonstrate compliance
Non-compliance results in Alternative Compliance Payments (ACPs) — penalty rates of $25–$100+ per MWh — which set a ceiling on compliance REC prices.
Voluntary Markets
Companies, institutions, and individuals voluntarily purchase RECs to meet sustainability goals. The voluntary market is growing rapidly:
- Green-e Energy (administered by the Center for Resource Solutions) is the leading certification for voluntary RECs, verifying additionality and preventing double-counting
- Major corporate buyers include Google, Amazon, Microsoft, and Apple
- Residential "green power" programs from utilities are typically backed by voluntary RECs
Solar Renewable Energy Certificates (SRECs)
Some states with solar carve-outs in their RPS create a separate market specifically for solar generation:
| State | Active SREC Market | Approximate Price (2025) | |-------|:-:|:-:| | New Jersey | Yes | $80–$120/MWh | | Massachusetts | Yes (SMART program) | Varies by project | | Maryland | Yes | $50–$70/MWh | | Pennsylvania | Yes | $20–$40/MWh | | Washington, D.C. | Yes | $300+/MWh | | Illinois | Yes (Adjustable Block) | Varies by block |
For rooftop solar owners in SREC states, selling SRECs can provide significant additional revenue — potentially $500–$3,000+/year depending on system size and SREC prices.
What "100% Renewable" Actually Means
When a company or utility claims to be "100% renewable," they can mean different things:
Strongest Claims
- On-site generation: Company generates its own renewable electricity (e.g., Apple's Maiden, NC data center with adjacent solar farm)
- New PPA: Company signs a long-term contract for new renewable generation, providing the financing certainty needed to build the project (most "additional")
Moderate Claims
- Bundled RECs: Company purchases RECs along with the physical electricity from an existing renewable generator in their grid region
Weakest Claims
- Unbundled national RECs: Company purchases cheap wind RECs from a wind farm in a different grid region that would have operated regardless. The company's local grid mix is unchanged.
Understanding these distinctions matters for evaluating corporate and utility green claims.
RECs and Your Solar Panels
If you own rooftop solar:
- You automatically own the RECs from your system's generation
- Some net metering agreements require REC transfer to the utility — meaning you give up the "green" claim in exchange for bill credits
- In SREC states, you can sell SRECs for additional income while still using the electricity
- If you sell your RECs, you cannot claim your electricity is "renewable" — you've sold that attribute to someone else
Read your interconnection agreement and any SREC registration documentation carefully to understand your REC ownership.