Tesco and Shell are to buy the entire output of a controversial solar farm under construction on the Kent coast that was originally meant to power 100,000 homes.

The two companies have signed deals to purchase all the electricity generated by Cleve Hill, which is poised to be the UK’s largest solar farm when it goes into operation early in 2025.

The project won planning permission despite massive local opposition on the basis that it would power more than 100,000 homes. However, 65pc of the output has instead been purchased by Tesco, which says Cleve Hill will help it cut emissions by powering up to 144 of its supermarkets.

The remaining 35pc of output will be managed by Shell as it buys up sources of renewable electricity to power its growing network of EV charging stations.

Vicky Ellis, of the Kent branch of CPRE, the countryside charity, said: “This project was approved on the premise that it would power homes, not petrol stations and supermarkets.

“The irony of a major supermarket such as Tesco and a prominent oil producer such as Shell buying into the green energy market to run their petrol stations and supermarkets is not lost on us. We suspect this is another example of greenwashing.”

Cleve Hill is owned and financed by Quinbrook Infrastructure Partners, a US investment fund based in Houston, Texas, which specialises in energy projects.

The 860-acre scheme is being built near Faversham on the Graveney salt marshes, once renowned for its wildlife, especially many wetland bird species. The site is also surrounded by nature reserves.

The solar farm scheme has already generated years of protests. It was rejected locally but was finally approved by Alok Sharma, then energy secretary, in 2020.

The marshes are now being covered in 560,000 solar panels, creating a total capacity of about 373 megawatts (MW). Some panels will be built on steel frames almost the height of a double decker bus because of the flood risk. Batteries to store any surplus power generated will also be installed.

Cleve Hill’s capacity will be equivalent to half the output of a small gas-fired power station or a ninth of the output planned for the UK’s next nuclear power stations at Hinkley Point, Somerset, and Sizewell in Suffolk.

The project divided environmental groups, with Friends of the Earth welcoming it but the Campaign to Protect Rural England (CPRE), Kent Wildlife Trust and the RSPB opposing it.

Ms Ellis, who also lives near the site, said the CPRE supported green power projects but not at any price. She said: “Graveney Marshes is an extremely special place. It is flanked on three sides by protected nature reserves and was afforded high landscape value by Swale borough council.