THE politics of Northern Ireland are complicated, and the Renewable Heat Incentive (or Cash for Ash) scandal that’s brought Stormont to the brink is no exception.

It all stems from a scheme to increase the use of renewables as a form of heating. Businesses, farmers and others were offered large incentives to build solar, thermal and heat pumps, biomass boilers, and other heating systems that would burn wood pellets.

The executive wanted 10 per cent of the heat in Northern Ireland to come from these sources by 2020. There are similar schemes in Scotland, England and Wales, though Northern Ireland’s was far, far more generous.

A recent report by the auditor general pointed out that a Northern Ireland firm taking part in the scheme could earn £860,000 over 20 years, but a UK firm doing the same would only get £192,000.

Outgoing First Minister Arlene Foster was then the minister in charge of the Department of Enterprise, Trade and Investment (DETI), which was responsible for the scheme. There was £25 million set aside, but slow uptake saw an underspend of £15 million.

However, in April 2015 there was a significant increase in firms applying for the incentive. When there was a possibility the scheme would close, 984 applications were received in just three months – September, October and November 2015.

It was only in February 2016 that the schemes were closed, and only in November last year that the full scale of what had happened became known.

Seemingly, for years, whistleblowers had warned the executive that the scheme was being exploited: that people were signing up to 20-year schemes that would see them receive close to a million pounds for heating empty sheds.

There were also claims that large factories that had never before been heated were using the scheme to install boilers, and running the heating throughout the year to collect about £1.5m over 20 years.

An investigation by Northern Ireland’s auditor general, Kieran Donnelly, unearthed “serious systematic failings from the start” and found the scheme had “no upper limit on the amount of energy that would be paid for”.

“The more heat that is generated, the more is paid,” he said.

Some 1,946 applications were approved under the non-domestic RHI scheme; 98 per cent of them were approved.

The assembly’s Public Accounts Committee was told that a subsequent independent audit had found issues at half of the 300 installations inspected.

Of those, 14 fell into the most serious category where fraud was suspected, and payments to five of these have been suspended.

The scheme was closed to new applications but still continues to make payments to successful applicants.

As a result, more than £1 billion of public money is due to be paid out over 20 years, seriously denting the region’s block grant.

According to Johnathan Bell, the minister who replaced Foster as DETI minister in 2015, the First Minister and her predecessor Peter Robinson had tried to delay the closure of the scheme, and had attempted to diminish their responsibility.