Well, that was quite something, and tomorrow we'll hear from another key witness who knew of the flaws in the RHI scheme at an early stage.

Image source, AFP

Janette O'Hagan emailed her concerns about it the then DETI minister Arlene Foster less than a year after the initiative opened, but the points she raised weren't dealt with by the department.

We'll bring you the proceedings as they happen, so join is from 09:45 in the morning!

BBC News Northern Ireland

On an incredible day at the inquiry, a biomass boiler buinessman claimed that civil servants want to spread the blame for the disaster of the RHI scheme so that it doesn't all fall on them.

Image source, Press Eye

Brian Hood's companies sold heating systems, and he rejected a Department for the Economy claim that there was a "conspiracy of silence" in his industry about the flaws in the scheme.

"They want to spread the net out and spread the blame to everybody as much as they can," he said.

Northern Ireland would still have a renewable heat industry if the RHI scheme had been run properly, says Mr Elliott.

Image source, Getty Images

People who invested in heating systems through the scheme "in good faith" have been "very, very majorly let down".

"Some have been left in serious financial hardship... it's not been fair on them and it's not been fair on lots of people."

One customer was willing to pay have a biomass boiler flown from Austria to Northern Ireland in order to get it installed before the RHI scheme closed.

"Whatever it cost, [the customer] didn't care," says Mr Elliott, explaining that importing it by lorry could've meant missing the deadline.

Image source, Getty Images

He had staff "working 24 hours a day" to fit heating systems in time and installers were "taking boilers from everywhere throughout Europe to fulfill orders".

But business went "dead" when the scheme shut.

People "would've paid anything for a boiler" in the final weeks of the RHI scheme, says Mr Elliott.

"I've never seen a feeding frenzy like it in my life... the phone was rang off the hook with people looking equipment... people desperate to avail of the scheme."

Image source, Getty Images

Mr Elliott says his firm didn't urge people to get into the initiative before it closed because it already had more work than it could handle.

Up until then, it had been installing "about one" boiler a week but that jumped to 50 in the last two weeks of the scheme.

It felt like "this is the end of the world" to him when the announcement was made that the scheme would close because Future Renewables had about £200,000-worth of boilers ready to be imported from a supplier in Austria at the time.

In August 2015, DETI's Seamus Hughes replied to a query from Mr Elliott's company about changes to the RHI scheme.

Future Renewables also asked about possible grace periods for those entering the scheme ahead of the introduction of those amendments.

Image source, Getty Images

In his written evidence to the inquiry, Mr Hughes said that in reply he indicated that DETI was "exploring the possibility of a short grace period" with its solicitors and was waiting on the outcome.

"I also indicated that if anything could be done it would be for a very small number of applicants who were in an advanced stage in the process," he said.

Mr Elliott says that he was "aware it was becoming a tiered scheme."

A simple phonecall to a supplier or a Google search was all it took to find out the price of wood pellets for fuelling biomass boilers, says Mr Elliott.

One of the biggest issues, as we've heard many times, that led to the scheme vastly overspending was that the subsidy on offer was higher than the fuel used.

Image source, Getty Images

That wasn't noticed by DETI throughout much of the lifetime of the RHI scheme.

"Anyone working in this type of industry could tell you what it cost very easily," adds Mr Elliott.

It "never made financial sense" for people to install one large boiler rather than two smaller units that would've fallen into the more lucrative subsidy band on the RHI scheme, says Mr Elliott.

The subsidy rate for boilers up to 99kW was much higher than for bigger systems, and Mr Elliott says the "majority" of people put those in instead of a single burner.

The "numbers would never have stacked up for the customer" to install a big boiler, says the witness.

At a DETI consultation event about the scheme, officials outlined that multiple boilers would've been eligible under the scheme if they were hydraulically-separate systems.

When Mr Elliott spoke to people at trade and agricultural shows, the benefits of the RHI scheme were not a surprise to them.

"I can't understand how you could say they couldn't understand, because I'm not super intelligent so it wasn't that I knew something others didn't - everyone knew what the RHI was," he says.

Image source, RHI Inquiry

Mr Lunny asks if Mr Elliott was aware of whether or not any system he was installing was going to be the subject of an RHI scheme application.

"Yes, it was the only reason that equipment was being installed, " he replies.

"Without the RHI nobody would have bought the technology we were selling."

Agricultural shows - including Balmoral, Clogher Valley and Castlewellan - were fertile ground for business for Mr Elliott's firm Future Renewables and other renewable heating company.

The agri-industry was a "good fit for the use" of the heating systems on the RHI scheme, he says.

Image source, Press Eye

There was an "explosion of installers" soon after the RHI scheme was opened.

"They would've been all at the shows, all looking for the same business," he adds.

One of the "biggest winners" in the RHI scheme was the poultry industry but it wasn't the only sector that cashed in, according to Mr Elliott.

Warehouses, nursing homes, showrooms and many more types of businesses all got in on it and he says those that had a need for heat benefitted the most because they were saving on fuel costs as well as collecting the subsidy.

Image source, PA

Those who didn't have a heat requirement and installed boilers through the scheme just to heat empty spaces didn't get the same benefit, he points out.

Mr Elliott goes on: "The business case to install the RHI... no-one could've argued with it."

Mr Elliott has been unable to provide any of his marketing leaflets to the inquiry, and says he "got rid of them".

"We were afraid of a war-crimes tribunal," he jokes, before explaining that the industry has changed so much the adverting is no longer relevant.

Image source, RHI Inquiry

Mr Lunny displays a leaflet issued by a company called Solmatix that gives the example of a care home that could save £2,300 on oil and collect £11,700 in RHI payments per year.

The leaflet, from May 2015, uses the slogan "cash for ash" that has since become common parlance for the excesses of the RHI scheme.

Energy efficiency "just went out the window" when people realised how lucrative the RHI scheme was, says Mr Elliott.

"It was just essentially: 'Use it as much as you can - you can't lose'," he adds, saying that he made the discovery with the first biomass boiler he installed.

"All installers were advertising the same thing - 'cash for ash', 'earn as you burn'... everyone knew... including the customers - the more energy you used the more you got paid."

The only way someone couldn't have noticed that would've been if they were "blind and deaf", he adds.

"Most of the renewable industry" in Northern Ireland was aware that the RHI scheme was flawed, Mr Elliott has told the inquiry in his written statement.

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That included Mr Elliott's firm, but he has said he didn't take any action "as we thought that DETI would cap the scheme or amend" it to bring in into line with the similar initiative in Great Britain.

"It was widespread knowledge... that the incentive was too good to be true."

One of the first companies Mr Elliott's firms gave a quote to for a renewable heating system through the RHI scheme was a hotelier, who was "laughed at" when he told other buisnesspeople how generous the initiative was.

"All his mates... said: 'Ach, sure it couldn't be that that's true," Mr Elliott tells the inquiry.

But "word-of-mouth got out" whenever the money started flowing and the uptake on the scheme "just grew and grew from there".

Inquiry chair Sir Patrick Coghlin says there was a "traditional Northern Ireland scepticism, especially in Fermanagh" (above), which Mr Elliott agrees with, saying that his home county "is the best, of course".

Fellow Lakelands man Mr Lunny quips: "That's not controversial!"

With Mr Hood's intriguing evidence session at an end, there's a quick change of the inquiry's counsel as Mr Scoffield makes way for his colleague Donal Lunny.

Image source, RHI Inquiry

The next witness is County Fermanagh businessman Neil Elliott of Future Renewables Energy Systems Ltd and he makes an affirmation.

His business supplies, fits and maintains renewable energy technology, and you can find his written statement to the inquiry here, external.

One company was about to install a £1.2m renewable heating system using multiple biomass boilers from Mr Hood's firm, but he says that had to be "shelved" because it couldn't be put in before the RHI scheme was changed.

And it wasn't the only big order to be cancelled, apparently - he tells the inquiry that the changes to and the eventual closure of the scheme led to people who were installing boilers being left unemployed because of the pace at which DETI wanted to do it.

Image source, Getty Images

"It was a big announcement, what they ended up doing," he says, adding that the move caused major concern within the renewable heating industry.

"For someone overnight just to turn your method of sales off I felt was completely wrong."

He complained to politicians just as the scheme was about the close in early-2016, saying there should've been a grace period to allow the completion of installations that were in the pipeline.

Applications to the RHI scheme were fairly steady from April to August 2015 at a rate of about 40 to 50 a month, but the number jumped dramatically in the autumn.

In September it rose to 100, then to 504 in October and November saw 378 applications submitted.

Image source, PA

Mr Hood says his sales did not see any similar spike as "we weren't in the poultry industry".

He says that big poultry companies such as Moy Park, had experience of the Great Britain RHI scheme and viewed the Northern Ireland initiative "perhaps as more lucrative scheme", and therefore encouraged their farmers and suppliers to join it.

Mr Hood says he and others in the renewable heat industry would've been telling people who were thinking of installing biomass boilers to get on with it before changes were made to the RHI scheme.

"Common sense would dictate that everybody else would be using the same ploy to try and encourage businesses to purchase their products," he adds.

Image source, Getty Images

The changes "had to happen at some stage", but he says that there was no statistical data available detailing the progress of the scheme.

"Northern Ireland's a black hole, you just don't get any information - even ringing DETI, they couldn't tell me."

The questioning of Mr Hood moves on to the spring and autumn of 2015 when there was a significant spike in the number of applications to the RHI scheme, which eventually burst its budget.

Mr Scoffield quotes from an email Mr Hood sent to an energy consultant working for the Hastings Hotel group.

Image source, RHI Inquiry

Mr Hood said there was talk that changes would be made to the RHI scheme as DETI was "making moves towards impeding the abuse that's been taking place in the RHI poultry sector".

He tells the inquiry that details about the planned changes would generally have come from Brites - that's the trade name for the County Fermanagh wood pellet manufacturer Balcas.

"Those were really the main channel we had, and we had reasonably frequent conversations with them," he says.