Renewable Heat Incentive Inquiry examining botched energy scheme
Stormont agriculture official Chris Johnston answers questions from the inquiry
Inquiry set up after public concern over scheme's huge projected overspend
Retired Court of Appeal judge Sir Patrick Coghlin chairing inquiry at Stormont
Public evidence sessions expected to last until well into 2018
We've finished for the day but there's no respite for Mr Wightman as he'll be back another day for more questions.
Tomorrow morning we'll be joined by a familiar face - John Mills, who headed the energy division at DETI from 2014 and was Mr Wightman's boss, last appeared at the inquiry in March.
Do join us for more live coverage starting at 09:45.
We're off to grab some of those evening sunshine rays...
BBC News NI
There was a "total divorce" between the two Stormont departments that were involved with the RHI scheme, according to the inquiry chair.
Image source, PacemakerSir Patrick Coghlin said officials in the agriculture department didn't communicate concerns with the initiative to officials in the enterprise department, which had responsibility for running it.
He made the point after agriculture official Chris Johnston agreed that paying attention to a key flaw in the scheme had not been his "focus".
The "penny was starting to drop" at DETI in May 2015 that much more money would be needed for the the RHI scheme as demand was increasing, says Mr Aiken.
Spending forecasts showed that by the time the scheme was to close it would need more than double what the department believed it needed in 2015 to 2016.
Image source, Getty ImagesMr Wightman says that it "would no doubt have been a shock" to senior DETI finance official Trevor Cooper when he was informed about how the scheme was running.
He drew Mr Cooper's attention to the fact that even if the scheme was to close early to new applicants, £22m would be needed each year to fulfil the spending commitments.
DETI had been working up its policy for developing the RHI scheme in March 2015 - a plan that included the introducton of cost control. It was intended that the changes would come into force in autumn that year.
In communication with Fergal Hegarty of the renewable energy firm Alternative Heat that month, DETI official Seamus Hughes gave an outline of what was being considered, but didn't mention the intention to reduce the subsidies on offer.
Image source, Getty ImagesMr Hegarty sent that information on to colleagues and said: "He hasn't disclosed as much as I hoped he would."
The communication between DETI and those in the energy industry was regular, says Mr Aiken, and he asks Mr Wightman if he considered why industry figures "were on the phone all the time wanting to know about changes".
Mr Wightman accepts that there was a "naivety" on the part of the DETI officials and they didn't "expect the industry to run with" and "plan ahead" using the information the department offered.
Dr MacLean is concerned about the lack of face-to-face communication between the members of DETI's energy division in spite of the fact that their offices were mostly on the same corridor.
That's in departmental HQ in Nertherleigh, just a stone's throw from where the inquiry is sitting in Stormont's Parliament Buildings.
Image source, DETIHe says he gets the impression that "people will go back to their office and type out an email, maybe pick up the phone".
Mr Wightman says there were "a number of silos" in the department compared with his experience in the Department of Regional Development, where he had worked before.
"There was an awful lot of communication done by email, a lot more than I would have been used to," he says.
It's "totally accurate" to say there was a "complete lack of clarity" in Mr Wightman's understanding of the budget for the RHI scheme in March 2015, he says.
In his email to the finance officials, he said he wanted "urgent clarification" on whether unspent money from previous years could be carried over and he also wanted to know what the maximum budget for the scheme would be.
Image source, RHI InquiryMr Aiken says Mr Wightman had a "moment of realisation" about the scheme's costs at that time.
The witness agrees, saying the "situation gradually got worse" over the following months and reached "crunch time" in May that year, causing a "sense of panic".
Mr Wightman emailed DETI finance officials in March 2015, saying that more money would be needed to fund the RHI scheme because the number of applications had increased and was "expected to remain high".
He said there were about 200 applications expected to come from the poultry sector and it was important that the budget was managed carefully.
Image source, Getty ImagesThe monthly spend on the scheme at that point was £800,000 and he expected that to increase by £60,000 a month, meaning that a year down the line it would be topping £1.5m a month.
"My concern is that these projections might be a little conservative," he wrote.
With Mr Johnston's session before the inquiry at an end, it's the turn again of Stuart Wightman.
He was in the witness chair yesterday and he's back to take a few more questions on his role as a DETI civil servant running the RHI scheme from the summer of 2014.
Image source, RHI InquiryYou can find his witness statement on the inquiry's website, external.
The inquiry's junior counsel Joseph Aiken is leaning he questioning this afternoon.
Mr Anderson sent a WhatsApp message to Mr Johnston in the summer of 2017, by which point he had received a Section 21 notice compelling him to provide evidence to the inquiry.
The message read: "Please don't put the letters RHI in my emails any more."
Mr Johnston says he thinks that "quite innocently any mention of RHI in an email would mean that it would need to be submitted to the inquiry whether it was relevant or not".
Image source, Getty ImagesSir Patrick notes that leaving the term RHI out leaves it up to Mr Anderson or Mr Johnston to decide "whether or not those should be discovered even if they are about the RHI".
Mr Johnston says he has searched for every single email and submitted them to the inquiry.
"Did you have a codeword for it?" asks Sir Patrick, not expecting an answer.
When the announcement came that the RHI scheme was to close, the Irish BioEnergy Association (IrBEA) sent an email to Mr Johnston disagreeing with the decision.
It attached a draft press release Biomass Energy Northern Ireland (Beni), which criticised the decision to close the scheme.
Image source, RHI InquiryMr Johnston responded to that, advising the groups to meet with DETI and put forward their position.
It is put Mr Johnston whether it was appropriate for him to involve himself "the strategy" of these interested parties.
"I didn’t think of it that way at the time," he says.
Another string of messages between Mr Johnston and Mr Anderson, the academic, is being scrutinised.
On 8 February, 2016, DETI issued a press release stating that the RHI scheme was to close.
Mr Anderson messaged Mr Johnston saying: "You got?"
Image source, PAMr Johnston responds: "Indeed Mark from many sources other than confirm what we knew."
Mr Lunny asks him about this last line, saying that it "suggests you already knew... the scheme was going to close".
Asked when he "first acquired that knowledge", the witness says: "I had no idea exactly where I had heard that".
The inquiry panel members are clearly intrigued as to why Mr Johnston did not speak to DETI about the signals he was receiving from the renewables industry that there was going to be a rush to get their biomass boilers up and running before the RHI scheme subsidy rates were reduced.
"When you change rates you're often going to get a rush of people who come in - I don't think there's any secret in that," says the witness.
Dr MacLean asks if Mr Johnston assumed that DETI would've already known and therefore believed there was no need to tell the department.
Would it not have been important, he asks, to have informed the department "whose budgets were going to get the a-r-s-e kicked out of it".
"In hindsight that's very clear but at the time I didn't consider that this was going to be new information to DETI or something they didn't have," replies Mr Johnston.
Image source, Getty ImagesMr Johnston discussed planned changes to the RHI scheme that he'd been told about by DETI officials with the chief executive of Action Renewables.
Mr Lunny asks if he thought it was appropriate to discuss internal information people outside public bodies.
"I certainly didn't come away with any view that it was... top secret... otherwise I don't think I would have."
Mr Johnston explaining that he missed the "cash for ash" advertising at events run by Stormont's agriculture department because he spent much of his days at those "in the seminar rooms".
"I would have been arriving there and giving a couple of talks during the day which would turn into whole conversations," says Mr Johnston.
Image source, RHI InquiryMr Johnston says he would have also manned an Abfi stand in the non-trade sections.
"I did want to get into the trade area. I didn’t always get an opportunity to get in there," he says.
"If these signs were there I should have seen them but I don’t have any recollection."
Biomass boiler installers used the RHI scheme as a way of promoting their products, advertising them in fliers and posters as a way of collecting "cash for ash".
Inquiry chair Sir Patrick Coghlin pushes Mr Johnston on whether he saw any of that promotional material at events he attended.
"Many of these events were sponsored by the Department of Agriculture," says the chair, "many of them were attended by members of the Department of Agriculture."
"It was absolutely clear the way that this was being sold to farmers and installers … you got a lot of money for what you did - you never came across those?"
Mr Johnston says he did not.
Mr Johnston is being questioned again about the WhatsApp messages about the RHI scheme that he exchanged with Ulster University academic Mark Anderson, which were referenced earlier.
Mr Anderson says at one point that he'd seen some "RHI being blown into the sky today".
That was at a woodchip-drying business in Stewartstown in County Tyrone, where the boilers were not being switched off while the drying floors were empty.
Mr Lunny suggests that doesn't sound like an efficient use of heat and the witness says "that was my comment as well".
Yet Mr Johnston says he had never heard of or saw any of that before it broke in the media.
Inquiry panelist Dame Una O'Brien asks Mr Johnston: "Prior to the story breaking... did you have a talk or chat about any of the sorts of practices that are being illustrated? You never heard any rumours?"
Mr Johnson says he did not.
Mr Johnston says he did not know of any RHI claimants who were involved solely in what's been described as "parasitic woodchip drying".
That is a process in which biomass boilers were used to dry wood that was then fed back into the same boilers in a cycle designed to collect the overgenerous subsidy.
But he says he was aware of businesses that were drying woodchip for distribution, using a percentage of the previously dried woodchip for that purpose. He says that would make sense.
Mr Johnston says it would've been "crazy" for claimants to use their boilers solely to dry woodchip in order to collect subsidies from the scheme.
"You'd be caught out in an audit... it doesn't make any sense."
Image source, Getty ImagesSir Patrick calls time on the morning session - join us at 14:00 for more live coverage.
In an email exchange in June 2015, DETI civil servant Seamus Hughes and Mr Johnston were trading numbers on the department's targets for the RHI scheme.
Without getting into the sums, the figure for the total heat demand seemed to Mr Johnston to be quite high.
Image source, Getty ImagesHe points that out to Mr Hughes, saying that if the sums are right "it's a massive average load factor".
It was the first time he had brought up the issue to DETI but he never received a response.
There appears to have been a "total divorce" between Stormont's enterprise and agriculture departments, according to inquiry chair Sir Patrick Coghlin.
"It's one government for the people of Northern Ireland but there appears to have been absolutely no exchange between the departments when something could... appear to be badly wrong," he says.
Image source, RHI InquiryNot only was the agriculture department "positively promoting" the RHI scheme at a time when "it was leading to overspending of public money", but he says agriculture officials didn't feel it was their responsibility to flag up concerns with the initiative.
He tells Mr Johnston: "Your reaction appears to have been: 'Not my focus; DETI must know about it; there must be some other explanation.'"
Mr Johnston acknowledges that's a fair summary and he accepts that it "would be good" to have a closer link between the departments.