Shell Energy slips in Clean Power Index as British Gas climbs

Shell Energy UK has fallen sharply in the latest annual Clean Power Index, dropping from sixth place to thirteenth as its share of renewable supply declined significantly. The research firm behind the index, Matched Energy, reported that the company’s renewable share of total supply fell from 71 per cent to 50 per cent over the review period. This decline occurred despite a substantial increase in demand for its services, which grew from 3.6 terawatt hours to 4.6 terawatt hours. The report noted that the company’s renewable energy certificates did not keep pace with this rise in consumption, resulting in a lower overall score for matched renewable supply.

In contrast, British Gas improved its standing in the ranking, rising to a score of 42 per cent renewable matched supply. This improvement followed an investment by its parent company, Centrica, in the biogas firm Gasrec last July. Gasrec provides bio-liquefied natural gas, and the equity deal is credited with enhancing British Gas’s renewable profile. The index tracks data from energy suppliers based on public records held by Elexon, the National Energy System Operator, and the Office of Gas and Electricity Markets, covering the period from April 2025 to March 2026.

The Clean Power Index measures how much renewable electricity suppliers deliver in the specific half-hourly periods when their customers use power, rather than relying solely on annual certificates. Among household suppliers selling a renewable tariff, whole-portfolio scores varied widely. Good Energy led the pack with a high of 87 per cent renewable matched supply, while Ovo recorded a low of 2 per cent. Other suppliers included Octopus Energy at 67 per cent, Pozitive Energy at 76 per cent, 100 Green at 61 per cent, and So Energy at 59 per cent. EDF, E.ON Next, and ScottishPower scored 19 per cent, 15 per cent, and 14 per cent respectively. Four other household suppliers, including Fuse Energy and Utility Warehouse, did not make renewable claims and scored zero per cent.

Matched Energy warned that no tariff sold as 100 per cent renewable delivers renewable power in every hour of customer usage. The firm highlighted that customers using heating in the evening during winter months are likely to be powered by gas rather than renewables. Even the top-ranked supplier, Good Energy, does not cover 13 per cent of its customers’ usage with renewables, meaning a significant portion of energy consumed is non-renewable. The research firm argued that current regulations treat all renewable tariffs as a single product, leaving customers without a way to distinguish between suppliers that purchase renewable energy certificates and those that buy renewable power to match specific usage times.

The index’s founder, Joe Kwiatkowski, stated that the current rules allow labels to claim something the product does not deliver in real time. He emphasised that renewable claims should be measured in the hours the power is actually used. This approach would allow consumers to see the difference between suppliers and ensure that the premium paid for green tariffs goes towards renewable power, storage, and flexibility for the hours that require it. The firm has called on the regulator to require hourly evidence behind renewable tariff claims to improve transparency for consumers.

Good Energy’s managing director of supply, Fran Woodward, supported the methodology, stating that the company believes hourly matching is the future of energy transparency. She noted that this method shows how much clean power is being delivered when customers actually need it. The Clean Power Index is peer reviewed by researchers at Oxford University and Imperial College, as well as energy suppliers. It is also used by the comparison site Uswitch to rank energy tariffs. The index ranks 28 suppliers in total, of which 14 sell energy to households and ten market a renewable tariff.