What is green web hosting, and how can you check a host's claims?

Every website runs on servers that use electricity 24 hours a day, every day of the year, along with the cooling that keeps them from overheating. Data centres are a significant and growing share of the world’s electricity use, and the rise of AI has accelerated that growth. Choosing a green web host is one of the simplest ways a business can cut the footprint of its website.

But “green” is an easy word to put on a website. Here’s how to tell what it actually means.

The three kinds of “green” claim

• Renewable electricity. The data centre’s electricity is matched to renewable generation, such as wind, solar or hydro. This is the strongest claim, if it can be backed up.
• Offsetting. The host pays for projects, such as tree planting, intended to balance out emissions. Useful as an extra, but weaker on its own, because the electricity itself may still come from fossil fuels.
• Efficiency. Modern hardware and cooling that use less energy for the same work. Good to have, but it reduces emissions rather than removing them.

How renewable electricity is proven in the UK

In the UK, renewable electricity is tracked through Renewable Energy Guarantees of Origin (REGOs), a scheme run by Ofgem. Each REGO certifies that one megawatt-hour of electricity was generated from a renewable source. When a supplier sells “100% renewable” electricity, REGOs are how they back it up. Ask a host which supplier provides their data centre’s electricity and whether it’s REGO-backed.

Five questions to ask any “green” host

1. Which data centre is my website in, and who supplies its electricity?
2. Is that electricity certified as renewable, and by whom?
3. Does the claim cover the servers themselves, or only the office?
4. Is offsetting used in addition to renewable electricity, or instead of it?
5. Can you share the evidence for my own sustainability reporting?

Check any website in seconds

The Green Web Foundation keeps a public directory of hosts that have shown evidence of running on green energy. You can check any website address with their free Green Web Check tool.