November 2, 2025
Summer sun, winter gas
Show HN: Open data reveals “100% renewable” UK energy isn’t really 100%
Commenters torch “100% green” claims: offsets, biomass brawls, fraud fears
TLDR: A new open index shows UK “100% renewable” tariffs don’t match what you use hour by hour; some are only ~55% in practice. Commenters blasted certificate ‘greenwashing,’ argued over biomass vs nuclear, and debated whether this is fraud or just outdated rules—and why it matters to bills and climate.
The internet just found out that “100% renewable” power in the UK isn’t really 100%, and the comments are on fire. A new open Matched Clean Power Index shows hour-by-hour reality: summer solar can be “claimed” to cover winter evenings fueled by gas. Translation: your 6pm January heating is likely fossil, even if your bill says green. The shocker? Some “100% renewable” brands score only 55%. Good Energy clocks 88%, Octopus comes in at 69%.
Cue outrage. One camp screams greenwashing, with djoldman lumping this into the “offsets” bucket: paying for certificates while burning fossil. Another camp says the rules are old, not evil, but dmboyd isn’t buying the “not fraud” line, arguing there’s “no accountability” so of course some fraud sneaks in. The spiciest showdown: biomass vs nuclear. PaulKeeble drags Drax for “burning the world’s forest” and rages that nuclear scores low, sparking memes about “paper electrons” and “summer photons time-traveling to January.”
Meanwhile, evolve2k says Australia’s “Green Power” looks just as broken and begs for a local index. The project’s cofounder bensg drops the full rankings link and invites audits, flexing the open data and a published methodology. Bottom line: commenters want real-time matching, storage, and honesty—not vibes and vintage 2003 rules.
Key Points
- •A certificate-based system from 2003 allows suppliers to claim renewable generation at different times than when customers consume electricity, causing mismatches.
- •The Matched Clean Power Index uses hourly data from the National Energy System Operator, Ofgem, and Elexon to assess real-time renewable matching.
- •Results show Good Energy at 88% renewable matching and Octopus at 69% across nearly 30 TWh, with some '100% renewable' tariffs only 55% matched.
- •Renewables now provide between 5% and 80% of Britain’s power depending on weather and season, but the system still trades in paper claims, not physical delivery.
- •Next steps include making data widely available, adding nuclear to provide a full low-carbon picture, and engaging policymakers to support Clean Power 2030.