In evidence which has led to fresh concerns about how many of the ‘cash for ash’ boilers were primarily or solely installed to milk the subsidy, a Stormont minister has confirmed that of 2,128 applications some 1,305 involved “new heat”.

The revelation raises fundamental questions about the environmental credentials of a scheme which was intended to incentivise businesses to replace existing oil or gas boilers with more environmental alternatives but which has led to a proliferations of boilers burning where previously there was no heat source at all.

And the figures show that of the 1,305 applications where there was no history of heat just 10 (0.7%) have been rejected. A further 125 remain undetermined, almost a year after the scheme was closed.

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Last night the Ulster Unionist MLA who uncovered the new information said he was “shocked” at what he had discovered and questioned whether it indicated that an even higher proportion of boilers than previously thought are predominantly there to make money.

Meanwhile, DUP deputy leader Nigel Dodds has said that leaked emails revealed yesterday by News Letter raise issues “of the utmost seriousness” and need “rigorous investigation”. The emails show that some energy firms had detailed inside information about the plan to rein in the scheme four months before cost controls were implemented – with the source of the information allegedly being departmental officials.

Not all of the ‘new heat’ RHI applications will involve abuse of the scheme, nor even situations where boilers have installed for the predominant purpose of making money.

It is known that a very significant proportion of the applications were for poultry sheds, many of which may have been new buildings.

And other businesses installing biomass boilers could have chosen to do so at the same time as building a new office or factory which necessarily would not have had a history of being heated because it did not previously exist.

Nevertheless, the scale of the applications for ‘new heat’ have raised fresh concerns not only about the potential for waste and abuse in the scheme but about the level of monitoring of the scheme, given that no one appears to have raised any concerns about so many boilers being installed in areas which had no history of heating.

The scheme was only ultimately closed down when it became clear that it was going to blow apart the department’s budget if it was allowed to stay open.

Responding to an Assembly question from UUP MLA Harold McKee, Economy Minister Simon Hamilton said: “Each application is assessed against the Regulations, which allow support under the scheme for a new heat use.”

Mr McKee told the News Letter that it was “beyond belief that such a weakness existed in the roll-out of this alleged environmental scheme”.

The South Down MLA said: “We have repeatedly been told that the policy behind the RHI scheme was to wean businesses away from burning fossil fuels, such as oil and gas, and onto more sustainable sources of heat like biomass.

“In fact, when Arlene Foster first introduced the regulations to the botched scheme in 2012 she specifically said it was to provide businesses with ongoing financial support when switching to renewable heating. This is something that was even reiterated by Simon Hamilton only this week.

“We now know that was not the case. The revelation that so many businesses now have biomass boilers in place, when previously they had no need for any heat at all, has revealed another fundamental flaw with the overall scheme.”

Raising fresh questions about the RHI debacle, Mr McKee added: “Is it a case that there are an even larger than envisaged number of businesses across Northern Ireland who have burners in place when they don’t actually need them?