Scheme was supposed to battle climate change but could cost £400m
The Renewable Heating Incentive scheme at the centre of the 'cash for ash' controversy was set up in 2012.
It was supposed to help businesses and the public sector with the cost of installing environmentally friendly heating systems, including wood pellet burners, as part of the battle against climate change. Current Northern Ireland First Minister Arlene Forster was the minister at the energy department when it was introduced.
Her successor Jonathan Bell closed the scheme to new applicants in February after a spike in applications and a whistleblower made allegations that it was being abused. One of the claims was that a farmer aimed to collect £1m over 20 years to heat an empty shed. There are fears that flaws in the scheme could cost the UK taxpayer £400m (€475m).