RHI: Timeline of a scandal
November 1 2012
Northern Ireland's Renewable Heat Incentive scheme is introduced as a way to increase the non-domestic use of renewable heat technologies. Eligible applicants are entitled to subsidies over 20 years, but unlike a corresponding scheme in Britain, payments are not capped.
August 26 2013
Enterprise minister Arlene Foster is first contacted by a whistleblower in relation to the RHI scheme.
September 3 2013
Second email sent to Mrs Foster's personal account by whistleblower outlining concerns over RHI. Meeting arranged with departmental officials but "concerns were not taken sufficiently seriously," DUP later says.
Whistleblower sends follow-up email which further outlines problems with RHI and how it is being financially abused. She later claims her concerns were “swept under the carpet”.
RHI is made available to domestic customers, who can receive a grant to assist in upfront costs to instal renewable heating technology, and an annual payment for seven years to cover additional costs.
DETI (Department of Enterprise, Trade and Investment) is due to seek reapproval of RHI from Department of Finance and Personnel (DFP), but this is not done due to “administrative oversight” and changes in staff.
A Northern Ireland Audit office report later states DETI only realised the oversight in May. Potential opportunity to implement cost control measures missed.
September to November 2015
Huge spike in non-domestic RHI applications after officials announce plans for cost controls. A total of 984 applications are received, almost as many as those submitted in previous 34 months.
November 18 2015
DETI introduces changes to the RHI scheme, including tiered tariff for small and medium commercial biomass and annual cap on payments.
Second whistleblower contacts Mrs Foster identifying how a farm shed and factories with large boilers were running heat 24 hours a day just to make money through the flawed subsidy system.
DETI minister Jonathan Bell announces intention to close the scheme to new applications. An investigation gets underway.
The Northern Ireland Audit Office concludes there was “serious systematic weaknesses from the start” and highlights how spending was “potentially vulnerable to abuse”.
In an interview with The Irish News, Mrs Foster dismisses criticism of her oversight of RHI, saying she couldn’t be over “every jot and tittle” in her department.
Stormont’s public accounts committee hears from witnesses, including Department of Finance permanent secretary David Sterling who says he “can’t satisfactorily explain” why a review into RHI did not take place during his time as head of DETI.
Senior members of Ofgem E-Serve also reveal there were no minutes taken of formal meetings between themselves and departmental officials between August 2014 and November the following year.
First Minister Arlene Foster resists calls to step aside for an investigation into RHI following a BBC Spotlight report highlighting the scandal.
December 14 2016
The First and Deputy First Ministers ask for the assembly to be recalled to discuss RHI. Arlene Foster later survives a vote of no confidence during a chaotic assembly session. She describes the failure to include cost-controls as the "greatest political regret of my life" but insists she has acted "with the highest level of integrity".
December 15 2016
Former DETI minister Jonathan Bell breaks DUP ranks to speak to the BBC. He claims advisers to Arlene Foster attempted to remove her name from documents linked to RHI and two top DUP advisers "were not allowing this scheme to be closed" at the point when costs were spiralling out of control in autumn 2015. The claims are denied by Arlene Foster and named advisers Timothy Johnston and Andrew Crawford.
January 4 2017
Arlene Foster again says she will not stand down over the RHI scandal, claiming that some calls for her to do so are "misogynistic".
Biomass boiler owners have formed a group to deal directly with government officials proposing changes to the scheme.
January 5 2017
Former DUP MLA David McIlveen criticises Mrs Foster for what he describes as the RHI "omnishambles". He says she has "seriously misjudged" public anger.
January 9 2017
Martin McGuinness resigns as deputy first minister as Arlene Foster continues to resist Sinn Féin demands to stand aside until a preliminary report from an inquiry. His resignation also removes the First Minister from office.
January 13 2017
RHI inspectors at OFGEM say they have suspended payments at more than half of the 63 boilers they have audited.
January 16 2017
An election is called after Sinn Féin refuse to nominate a deputy first minister to replace Martin McGuinness.
January 19 2017
Andrew Crawford, a former special adviser to Arlene Foster, resigns after claims he exerted influence over the flawed energy scheme to keep it running. He denies the claim but says has has "become the focus of the story".
January 21 2017
DUP MLA Jim Wells reveals that four members of his family, including his brother, installed wood pellet boilers under the RHI scheme but says he has no financial interest in the businesses.
January 23 2017
MLAs back plans to cut the cost of the RHI scheme by lowering the tariff paid to claimants. The regulations aim to save £30m in the 2017/18 budget - but will only apply for 12 months.
January 24 2017
A judge issues an interim injunction preventing the publication of hundreds of names of RHI claimants who are members of the Renewable Heat Association. Finance minister Máirtín Ó Muilleoir announces a public inquiry, to be chaired by retired appeal court judge Sir Patrick Coghlin.
February 3 2017
Legal papers are lodged by the Renewable Heat Association to ensure 20-year payments to RHI claimants are honoured.
February 8 2017
Attorney General John Larkin says he is considering challenging the legality of the entire Renewable Heat Incentive scheme because it was introduced without going before the full executive.