Claims made by the company behind plans to build a wind farm near Gargrave were misleading, the advertising standards watchdog has ruled.

Energiekontor UK included misleading information in promotional material on the amount of electricity likely to be generated from the proposed three turbines at Brightenber Hill, the Advertising Standards Authority has ruled.

The ruling, published on the authority’s website this week, upheld one complaint made by the Friends of Craven Landscape (FoCL), but dismissed four others, including claims about minimal disruption during building work and a claim that the site was one of the “least sensitive” in Craven.

In a leaflet and factsheet issued to residents and at a public exhibition at Coniston Cold Village Hall in December, the company claimed that the three 100m high turbines would produce enough electricity on average to power 3, 670 homes in Craven.

But the ASA, following a six-month investigation, noted that the calculations used information from the Department of Energy and Climate Change (DECC) for the average capacity for an onshore windfarm anywhere in the country.

It said the information was misleading because, although the company had used conservative estimates, it had not made it clear that claims were estimates based on average capacity factors and not specific to the Brightenber site.

Chris Emmett, spokesman for the Friends of Craven Landscape (FoCL), said: “We knew the information was wrong the moment we saw it - there’s just not enough wind up there.

“This was Energiekontor’s chance to engage with the public but instead they chose to mislead us. To make matters worse, they’ve included these dodgy performance figures in their planning application.”

Energiekontor’s project manager Justin Reid said: “The claim has been upheld because we used definitive rather than conditional language based on the use of one word and not the actual original claim which related to FOCL’s flawed misinterpretation of the power output of turbines.”

He said future wording on advertising material would use the word “could” instead of “will” when referring to the number of homes to be powered by the turbines.

He added: “The ASA accept that calculations we use to arrive at the number of homes powered are correct and they make it very clear that we have used a conservative estimate. Technically, it comes down to the use of one word, when we were careful not to exaggerate and actually underplay the potential benefits of the project.”

FoCL’s other complaints about claims of average wind speeds in the area and that the area was one of the least sensitive areas in Craven, were not upheld. The ASA also found no breaches in claims made about minimal disruption to road users during building work or savings of more than 7, 741 tonnes of CO2 each year.

Mr Reid said: “The ASA do not dispute our view that this is a windy site with good wind speeds and indeed one of the least sensitive sites in Craven that, when operational, could potentially save more than 7,741 tonnes of CO2 each year.”

Mr Emmett said FoCL had repeatedly asked for information gathered from the company’s on-site wind survey.

“Time and time again we’ve asked Energiekontor if Brightenber Hill is such a good place for a windfarm. Why deliberately use outdated national data? Why withhold the results of the 18- month onsite wind survey?”

However, Mr Reid said his company had its own concerns about the campaign group.

“We are very concerned with the integrity of the material that has been distributed by FoCL which we consider to be incorrect in a number of areas,” he said.

The application is expected to go before Craven District Council’s planning committee in late July.