In its proposal to the justice minister for the Desertcreat college, Sheridan & Hood said the department could turn the heating system's running costs into a "profit".

Mr Hood suggested that small 99kW boilers, which were eligible to collect the RHI scheme's most lucrative subsidy, could be used.

Image source, Getty Images

Therefore, the department could pocket just under £900,000 over the scheme's 20-year span.

The letter was sent less than a month after the scheme opened in November 2012, and Mr Scoffield asks the witness how he found out so quickly about "how beneficial the scheme could be".

Mr Hood said his firms contacted the Department of Enterprise, Trade and Investment (DETI), which set up the initiative, and then did their "due diligence" and a "lot of research" to establish that the figures they were seeing about what the scheme was offering were "the truth".

A key focus of the inquiry's questioning of Mr Hood will be his firm's involvement with a proposed new police, prison and fire officers training college at Desercreat in County Tyrone in 2013.

It was being planned by Stormont's Department of Justice, and Sheridan & Hood received a tender inquiry from a building company that was interested in constructing the whole project.

Image source, DoJ

The inquiry's senior counsel David Scoffield QC asks Mr Hood why he wrote to the then justice minister David Ford to outline the RHI scheme's benefits for the project.

"I noticed that they were using two very large... boilers that were outside the RHI scope," he says.

The plans were for 10 to 12 separate buildings on the site and Mr Hood saw no reason why there could not be separate small biomass plants for each building, which would qualify for the scheme.

Sheridan & Hood was awarded a certificate in March 2013 by the then DETI minister Arlene Foster for being the first company in Northern Ireland to become accredited on the RHI scheme.

Mr Hood tells the inquiry that his company had installed biomass boilers in its premises and applied to the scheme and was approved.

Image source, PA

He says that it asked the department for a photo with the minister to mark the award as a "media exercise".

That was a "demonstration practice to our consumers that it is a viable scheme and it is working and we invested in it ourselves".

Our quick search of the Public Record Office of Northern Ireland helps to dig up an archived press release about the meeting between Mr Hood and Mrs Foster, external.

Brian Hood was a managing director of two of companies that had involvement with the RHI scheme.

One of those was Sheridan & Hood, a Belfast building and engineering firm that developed biomass energy systems but which went into liquidation in 2015, external.

Image source, RHI Inquiry

The other was BS Holdings, an engineering, manufacturing and design business that makes biomass plant.

His firms supplied and installed biomass boilers through the lifetime of the RHI scheme.

Mr Hood has given three written statements to the inquiry, which can be found here, external, here, external and here, external.

BBC News Northern Ireland

It emerged that a woman who tried to draw Arlene Foster’s attention to abuses of the RHI scheme less than a year after it opened has told the inquiry that it was "clear" that her concerns would not be investigated.

Janette O’Hagan has been described as a whistleblower, who was one of the first people to raise issues about the scheme’s overgenerosity.

Image source, Press Eye

She emailed the then enterprise minister in 2013, telling her that the initiative "pays participants to use as much heat as they can".

She met officials from Mrs Foster’s department who were working directly on the scheme, and has told the inquiry that that they did not "share my concerns that the people would abuse the scheme".

BBC News Northern Ireland

An independent inquiry into the RHI scandal was established in January last year by the then finance minister Máirtín Ó Muilleoir.

He ordered it in the wake of the huge public concern and what was then a developing political crisis surrounding the scheme.

The RHI Inquiry began in November and Sir Patrick Coghlin (below), a retired Court of Appeal judge, is its chair and has been given full control over how it will operate.

Image source, Pacemaker

It will look at:

• the design and introduction of the RHI scheme
• the scheme's initial operation, administration, promotion and supervision
• the introduction of revised subsidies and a usage cap for new scheme claimants in 2015
• the scheme's closure

For more information on the RHI Inquiry, you can read our handy Q&A.

When the scale of the overspend emerged, public and political concern rocketed.

As the minister in charge of the Stormont department that set up the RHI scheme, the Democratic Unionist Party (DUP) leader Arlene Foster faced calls to resign from her role as Northern Ireland's first minister in December 2016.

Image source, PA

She resisted, and Sinn Féin's Martin McGuinness then quit as deputy first minister in protest at the DUP's handling of what had by then become a full-blown political crisis.

That move brought about the collapse of the Northern Ireland Executive. Now, more than a year on from that, Northern Ireland remains without a devolved administration.

You can find much more detail on the RHI scheme in our need-to-know guide.

The budget of the RHI scheme ran out of control because of critical flaws in the way it was set up.

Claimants could effectively earn more money the more fuel they burned because the subsidies on offer for renewable fuels were far greater than the cost of the fuels themselves.

Image source, Getty Images

The most recent estimate for the overspend was set at £700m, if permanent cost controls aren't introduced.

The massive overspend bill will have to be picked up by the Northern Ireland taxpayer.

The Renewable Heat Incentive scheme - or RHI for short - came to the fore of the Northern Ireland public's knowledge in late-2015... and the fallout from the scandal attached to it is still being felt in the region's politics today.

Image source, Getty Images

The scheme was set up by the Northern Ireland Executive in 2012, as a way of encouraging businesses to switch from using fossil fuels to renewable sources for generating their heat.

Those who signed up were offered financial incentives to buy new heating systems and the fuel to run them.

Thanks for joining us for our live coverage of the Renewable Heat Incentive Inquiry.

We'll be hearing from the first witnesses to give evidence in the inquiry's second part, which concerns the initial operation and running of the botched energy initiative.

First up will be Brian Hood, who ran a firm that installed biomass boilers, and was also one of the first people to notice how lucrative the RHI scheme could be.

Proceedings begin shortly, so stick with us throughout what promises to be an intriguing day.