Renewabl’s guide to unbundled EACs, or renewable energy attribute certificates

Read the full version of the guide on Renewabl's website.

There’s more than one way to buy renewable energy. If your electricity comes from the grid, you can’t separate green from grey – but energy attribute certificates (EACs) offer a practical workaround. Called GOs (in Europe), REGOs (in the UK), and RECs (in the US), certificates let buyers claim credit for 1 megawatt‑hour (MWh) of renewable electricity delivered to the grid.

Renewable EACs are market-based instruments recognised by national energy bodies. They increasingly support granular matching – even down to 24/7 hourly alignment between generation and consumption. This guide explains how EACs work, where to get them, and how to use them in clean energy procurement.

Tl;dr

• Renewable energy attribute certificates (EACs) have emerged as a low-risk way to source renewable energy
• EACs allow corporate buyers to claim clean power, even if their electricity offtake comes from a local grid
• By proving that a traceable and verifiable volume of clean energy has been purchased at the source, these certificates back up claims that a firm is advancing its net zero commitments 
• EACs provide additional revenue for energy sellers and send demand signals for more renewable to be built 
• When EACs are 24/7 hourly-matched, the benefits are magnified as consumption is linked to generation more accurately and in a granular way
• While purchasing EACs is meant to be straightforward, there are some barriers to entry and strategic complexities to consider

Part I: Introduction to renewable certificates

What are renewable energy attribute certificates? EACs / REGOs / GOs 

EACs are an established instrument for buying, verifying, and trading renewable power. Each one represents 1 megawatt-hour (MWh) of electricity generated from renewable sources; typically solar, wind, or hydro.

EACs have different names in different regions. They're called Renewable Energy Guarantees of Origin (REGOs) in the UK, Guarantees of Origin (GOs) in the EU, and Renewable Energy Certificates/Credits (RECs) in North America. Australia calls them Large-Scale Generation Certificates (LGCs). Other jurisdictions offer International Renewable Energy Certificates (I-RECs). 

These are all national and regional variations, but energy attribute certificate (EAC) is the generic catch-all term.

Regardless of label, EACs contain key details (attributes) about how, where, and when the clean power was produced. They include:

• The point of origin (generation facility)
• The month in which they were generated
• The specific renewable energy technology (solar, wind)
• The rate of carbon emissions (‘zero’ for a renewable generation plant)
• A stamp of authenticity from the national EAC registration body

Why do EACs matter?

EACs or RECs (renewable energy certificates) aim to increase the accountability and transparency of renewable energy production. 

EACs demonstrate that an organisation has procured its power from a renewable plant despite physically off-taking it from the grid, where everything is mixed together. EACs provide verification and traceability, legitimising claims around achieving environmental goals. They also create demand signals for more renewable generation assets, like solar or wind farms, to be built.

How do renewable energy certificates work?

National regulatory agencies like Ofgem in the UK act as EAC registries. They issue certificates to clean energy producers, who are then able to sell them to their off-taking customers for a volume of power equivalent to their actual usage. 

Once a buyer becomes sole owner of an EAC, they can ‘retire’ or ‘cancel’ it with the registry (the exact language depends on the jurisdiction). This indicates that the clean power has been consumed and validates their renewable energy claims. EACs can be traded multiple times, but once cancelled, they cannot be re-sold, ensuring no double-claiming of renewable power.

For example, if a buyer wants to use EACs to reduce scope 2 emissions, they would calculate their total power consumption for a given period and determine how many EACs are needed to meet their renewable energy targets. This could be the full amount of their consumption or just the portion not already covered by existing renewable contracts. After they’ve made the purchase, they cancel or retire their EACs with the registry and claim a corresponding amount of renewable electricity consumption. 

EAC cancellation

After being purchased, cancelling or ‘retiring’ EACs can happen in two different ways, based on whether or not a buyer’s local registry allows corporate buyers to have their own EAC registry account (some do, others don’t).

Option 01: The buyer has an account with their EAC registry

EACs are transferred from the energy supplier’s account to the buyer’s account. The company then holds these EACs until it retires them. 

Option 02: The buyer doesn't have an EAC registry account 

A broker or supplier retires the EACs in their own account and provides an attestation document to the buyer. This document includes the certificate type, volume, generation source, and confirmation of retirement. 

Corporates must provide proof of EAC procurement and retirement to substantiate their renewable energy claims. This includes certificate serial numbers, registry details, purchase contracts, and official retirement statements to confirm alignment with reporting periods.

Bundled or unbundled EACs?

Renewable energy certificates come in two formats, bundled and unbundled:

• Unbundled EACs are sold separate from the physical supply.
• A bundled EAC is sold with the physical electricity included in the same contract: Physical PPAs, where both the electricity and the associated EACs originate from the same renewable asset. Virtual PPAs, where the electricity and EACs are purchased from the same renewable project, but the electricity may not physically reach the buyer. Green tariffs, where both electricity and EACs are provided by an energy supplier (utility) in a single financial transaction.

In practice, you could buy bundled EACs directly from a clean power project, or from an energy retailer (supplier) that obtains the certificates from a project on your behalf. 

Unbundled EACs may also be procured from sellers or retailers. As the EAC buyer, you would take electricity from the grid as normal, then use your EACs to verify your renewable energy consumption and sustainability claims. 

To make the claim, EACs would be either cancelled on your behalf by the supplier or transferred into your own EAC registry account, allowing you to cancel them yourself. The method depends on the rules of the respective market in which you are operating.

“Whether an EAC is bundled or unbundled doesn't change its environmental impact. It's just a transactional choice. Bundling can be useful, but it doesn't automatically tell you things like where or when the energy was generated, or if it actually adds new capacity to the grid.”

– JP Cerda, CEO and Co-founder @ Renewabl

For more information about unbundled EACs vs green tariffs, read our procurement business case.

How 24/7 hourly matching adds value

EACs have traditionally been sold on an annual basis, however new platforms are enabling wide adoption of hourly-matched EACs. Using real-time generation data, they provide accurate links between clean renewable energy production and consumption. 

This is made possible through hourly time stamped energy certificates, also referred to as granular certificates (GCs). Granular certificates (GCs) would provide more detailed information about renewable energy generation than current options, improving transparency and credibility. 

In terms of availability, several regions have adopted granular certificates, enabling better tracking of renewable energy. For example, in Nordic countries like Denmark, Sweden, and Finland, electricity grid operators are pioneers in hourly tracking. The UK is working toward hourly certifications with its REGO system, and North America has implemented hourly RECs through platforms like PJM-GATS and M-RETS. 

While registries are working towards supporting this level of granularity, we can bridge this gap at Renewabl. To validate the hourly match, GCs are created to represent each of the underlying registry EACs. These GCs are given a time stamp which can be verified by aligning the unique registry EAC IDs with the metered generation data.

Find out more about hourly matching and its impact on procurement strategies.

Part II: EACs, regulation, and market developments

The EU has been a leader in setting rules and standards to advance the renewables transition. Three comprehensive regulatory regimes have been enacted or are on their way to final assent. With each new iteration, EACs have played an increasingly central role. 

The Renewable Energy Directive (RED III)

The Renewable Energy Directive (RED) establishes renewable energy consumption targets that must be achieved across the EU. RED III, the latest iteration, prescribes the format, content, time scale and validity of GOs. It also contains provisions that will allow regulators to intervene in the GO market if imbalances are detected.

Green Claims Directive

Sometimes called the ‘greenwashing’ directive, the Green Claims directive is written to discourage buyers from making exaggerated or unsupported statements about their sustainability efforts. Scheduled for enactment in 2028, the directive will establish a clear set of standards that make sustainability claims verifiable and comparable across the EU. 

Corporate Sustainability Reporting Directive

This set of recently-adopted EU regulations requires all large buyers to make regular disclosures about their sustainability performance. The aim is to help investors, consumers, and regulators evaluate corporate progress towards decarbonization and encourage buyers to develop sustainable operations.

Each of these rulebooks include measures to track progress and verify claims about the production or consumption of renewable energy. Brussels regulators have embraced EACs (in GO form) as a primary mechanism for achieving this.

Find out more about EU regulatory frameworks for renewable energy certificates.

Part III: Purchasing certificates – REGOs and GOs procurement strategies

Continue reading this article on Renewab's website.