How green is your energy supplier?
Why transparency matters in renewable power
The renewable energy market has never been more crowded, or more confusing. Across the UK, many suppliers claim to offer “100% renewable” power. But how do you know which of those claims are genuine, and which rely on clever accounting?
That’s the problem the Matched Clean Power Index set out to solve. By analysing public data, it ranks suppliers on how well they align renewable generation with actual customer demand. Good Energy topped the index for the second year running, showing that when it comes to renewable transparency, we’re setting the standard for truly green power. Here’s how, and why it’s important.
Is all renewable supply the same?
No – while many suppliers advertise 100% renewable electricity, the way that power is sourced and when it’s matched to your usage can vary significantly.
Most suppliers rely on paper certificates known as REGOs (Renewable Energy Guarantees of Origin) to certify their electricity as ‘renewable’. These certificates can be bought separately from the actual electricity they represent, and they don’t have to match the time the electricity is generated.
This means that a supplier can legitimately label the power used on a dark winter evening as renewable, by buying REGOs from solar generation in the summer.
We believe this is misleading, and it doesn’t support a greener electricity grid that matches how homes and businesses are actually using power.
Introducing the Matched Clean Power Index
The Matched Clean Power Index, first published in October 2025, is the first independent review of how UK energy suppliers are matching their customers’ usage with renewable generation in each half-hour of the day.
It uses publicly available information from Ofgem, Elexon and the National Energy System Operator – with a methodology reviewed by experts from academia, energy suppliers and organisations – to provide some much needed transparency into renewable energy tariffs.
The results revealed a huge difference between suppliers, with half-hourly matching scores ranging from 0% at the bottom to Good Energy’s market-leading 87% for the April 2025 – March 2026 reporting period. This makes Good Energy the highest-ranked supplier for time-matched renewable electricity in the UK by quite some margin.
We’re proud to be ranked #1 for British Made Renewable Electricity*
Why did Good Energy top the Matched Clean Index?
Good Energy directly purchases renewable power from over 3,000 independent British generators**. With our own in-house trading desk, we strive to create a fuel mix that matches how our customers are actually using electricity – by contracting directly with a wide variety of generators spread across the UK.
We believe this is the best way to help the UK grid to get to become 100% low carbon, as it helps to build a market for the variety of generation types needed to support this ambition at scale. Providing customers with information about when their energy use is being covered by renewable power also enables demand flexibility – reducing consumption or using storage technologies when the wind isn’t blowing and the sun isn’t shining.
The false green labels some suppliers continue to sell can finally be seen for what they are. This index gives customers real transparency into the true sources of clean power. We hope it encourages reform and moves the UK closer to genuine, time-matched renewable electricity.
Nigel Pocklington, CEO, Good Energy
Stop being sold the idea of renewable power, start getting the reality of it
As the UK works towards net zero, transparency around where our energy comes from is essential for building trust – and for ensuring investment goes where it’s needed most: into new, local renewable generation.
Renewable energy for home
100% renewable electricity and carbon neutral gas from the UK’s only B Corp Certified home energy supplier. Switching takes just 2 minutes.
Renewable energy for businesses
100% renewable electricity, with hourly matching data for large business customers. Plus 5* dedicated account management.
*Good Energy ranked #1 in the Matched Clean Power Index, an independent assessment of how closely UK suppliers match renewable generation to customer demand on a half hourly basis. Comparison verified at https://matched.energy.
**Good Energy sources power directly from over 3,000 independent renewable generators across Britain. Some of these smaller sites are not currently included in the Matched Clean Power Index dataset, which only includes accredited generators with publicly reported half-hourly data.
