A controversial plan to build a gas-fired electricity generating station between Hitchin and Stevenage has tonight been rejected.

The application – from a London-based company called Wymondley Power Ltd – proposed a 49.99 MW gas-peaking plant on Green Belt land near Little Wymondley to satisfy demand for electricity at peak times, for a 20-year period described as temporary.

Wymondley Parish Council, St Ippolyts Parish Council and 31 members of the community vehemently objected, citing Green Belt policy and other issues – and meeting at Letchworth’s Spirella Ballroom tonight, North Herts District Council’s planning control committee followed officers’ advice in refusing permission.

The site, next to the existing Wymondley Substation off Blackmore End Road, is a former landfill created during the construction of the A602, which is now used for the grazing of horses from eight stables.

The proposed plant would comprise 11 gas engines within casements, each with a 15-metre chimney and an array of cooling fans, with a 2½-metre security fence around the site.

Representatives from Wymondley were united in the view that it would be a blot on the landscape – and district council planning officer Kate Poyser agreed with them that the plant would be inappropriate for the Green Belt.

Ms Poyser wrote that the applicant, in her view, followed only a “conflicting and confused” process for selecting the site, and that there were therefore no special circumstances to set aside the Green Belt objection.

She added that the applicant’s proposal to return the site to its current state after 20 years might go unfulfilled if the operator went bankrupt, and that the land could “become an eyesore over time” – potentially forcing the district council to clear it at considerable expense.

Adrian Hawkins of Wymondley Parish Council stressed “growing concern among the public these days about air pollution” and said the villagers of Little Wymondley were particularly concerned about pollution from the proposed power station – with air quality around the Three Moorhens roundabout in Hitchin worse than that in parts of London.

Requesting refusal, he said: “We recommend heartily that there is a rethink.”

Wymondley Power Ltd director Andrew Troup urged the councillors to grant permission, telling them: “The support is needed for the grid, unfortunately. I wouldn’t be here proposing this on Green Belt if I had alternatives, I can assure you.

“We are sat here looking at the balance between harm and essential need. I can see both sides to this story. I’ve been around a long time.”

He suggested that there would be low pollution levels, and that the chimneys would not be visible from many roads or footpaths and would be shielded from some views by trees. He also mentioned a possible reduction to four engines with seven-metre chimneys.

When Councillor Harry Spencer-Smith queried where the extra demand was, Mr Troup cited “a change in the electricity delivery system, as we have a quarter of our power now coming from wind”.

The committee carried a motion to refuse planning permission by a majority. Councillors Harry Spencer-Smith and Ian Mantle abstained.