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Renewable energy certificates | The Outlet — Pilot Energy

Written by Pilot Energy | May 26, 2026 4:21:47 PM

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Renewable generator 1 MWh generated = 1 REC created WREGIS / GATS registry Bundled REC travels with the power (PPA / green tariff) Unbundled REC sold separately $1-5/MWh typical Strong claim: new project Additionality satisfied RE100 / CDP accepted Weak claim: existing gen No additionality Greenwashing risk

The short version

A renewable energy certificate (REC) is a tradable instrument representing one megawatt-hour of electricity generated from a qualifying renewable source. When a wind farm or solar plant generates 1 MWh, it creates one REC — a unique digital certificate tracked in a registry (WREGIS in the West, GATS in PJM, M-RETS in the Midwest). That REC can be sold separately from the underlying electricity, transferred to a buyer, and used to substantiate renewable energy claims.

RECs are the currency of the voluntary and compliance renewable energy markets. Utilities use them to demonstrate compliance with state renewable portfolio standards (RPS). Corporations use them to support Scope 2 market-based accounting claims and sustainability commitments to RE100, CDP, and other frameworks.

RECs do not guarantee zero-carbon electricity consumption: A REC represents that renewable electricity was produced somewhere on the grid — not that it was physically delivered to the buyer. Critics argue that widespread unbundled REC purchasing provides weak environmental integrity because it does not fund new renewable capacity. This debate is central to corporate sustainability credibility.

Bundled vs. unbundled RECs

Bundled RECs travel with the physical electricity they represent — they are embedded in a PPA or green tariff where the buyer receives both the power and the associated renewable attributes. Bundled RECs represent the strongest form of renewable energy procurement and are universally accepted by voluntary sustainability frameworks.

Unbundled RECs are separated from the electricity and traded independently. A coal plant can buy RECs from a wind farm and claim it delivers green power — the REC is the claim, regardless of what electricity is actually generated. Unbundled REC prices are typically $1–$5/MWh for generic green-e certified RECs, far below the cost of generating new renewable capacity. Critics argue this makes unbundled RECs an accounting exercise rather than genuine climate action.

REC registries and tracking

RECs are tracked in regional registries that prevent double-counting. In the western US, WREGIS (Western Renewable Energy Generation Information System) tracks renewable generation and REC creation and transfer. GATS (Generation Attribute Tracking System) serves PJM. M-RETS serves the Midwest. Each REC has a unique serial number, the generating facility, generation month, and fuel type. When a REC is retired (used to substantiate a claim), it is permanently removed from the registry.

The additionality debate

The most substantive criticism of unbundled RECs is that they fail the additionality test — they do not fund new renewable generation that would not otherwise exist. Buying a $2/MWh REC from a 20-year-old hydro plant provides no incremental climate benefit. Leading corporate sustainability frameworks — RE100, the Science Based Targets initiative, and the GHG Protocol's forthcoming 24/7 carbon-free energy guidance — are increasingly distinguishing between high-integrity procurement (new projects, matched temporally and geographically) and low-integrity procurement (cheap unbundled RECs from existing plants).

Common questions

What is a renewable energy certificate (REC)?
A REC is a tradable certificate representing one megawatt-hour of electricity generated from a qualifying renewable source. RECs are tracked in regional registries (WREGIS, GATS, M-RETS) and can be transferred to buyers to substantiate renewable energy and Scope 2 sustainability claims. One MWh of renewable generation creates exactly one REC.
What is the difference between bundled and unbundled RECs?
Bundled RECs travel with the physical electricity they represent — embedded in a PPA or green tariff. Unbundled RECs are separated from the underlying electricity and traded independently, often at very low prices ($1–5/MWh). Bundled RECs are universally accepted by sustainability frameworks. Unbundled RECs from existing generation face criticism for failing the additionality test — they do not fund new renewable capacity.
What is the additionality requirement for RECs?
Additionality means that a renewable energy purchase should fund new generation that would not otherwise have been built. Long-term PPAs and VPPAs with new projects satisfy additionality. Buying cheap unbundled RECs from existing facilities does not — the generation would have occurred regardless of the purchase. RE100, the Science Based Targets initiative, and other frameworks increasingly require additionality for credible renewable energy claims.
How are RECs used for Scope 2 accounting?
Under the GHG Protocol market-based method for Scope 2 greenhouse gas accounting, corporations can claim zero-carbon electricity consumption when they retire RECs matching their consumption. Bundled RECs from PPAs or green tariffs provide the strongest Scope 2 claims. Unbundled RECs are accepted under current standards but are increasingly scrutinized as the bar for corporate sustainability claims rises.
What does REC retirement mean?
REC retirement is the permanent removal of a REC from circulation after it has been used to substantiate a renewable energy or Scope 2 claim. Once retired, a REC cannot be resold or reused — it is the mechanism that prevents double-counting in the renewable energy market. RECs are retired in regional registries (WREGIS, GATS, M-RETS) by the organization making the renewable energy claim.

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