The school has become a building site with two large drilling rigs digging the bore holes, from which the energy will be collected
"It is pretty exciting to know we're helping the environment and doing something good in school".
That's what 11-year-old Dylan told me when I went to meet the pupils of Ysgol y Dderwen in Carmarthen.
The primary school believes in being environmentally friendly, so staff and pupils are getting rather excited about the fact that very soon, their site will be heated by renewable energy, that has been captured from underground.
Ground source heat pumps are being installed. But this is no ordinary plumbing job.
It takes two to three days to make each bore hole
Dr Aled Davies, who works for WDS Environmental, the company behind the project, explained: "The way we're collecting energy from the ground is through 24 bore holes.
"They each go about 100m (330ft) into the ground, and we're circulating through pipes in the bore holes, water and glycol, and that's collecting this temperature that's naturally in the ground.
"That's then taken to the plant room through a system of heat pumps, and all these pumps are doing is effectively compressing that energy to a higher temperature, which is then useful for the school for their heating and hot water needs."
School captures heat underground
The technology is now fairly common in homes, but few schools in Wales have tried it out.
It's being installed as part of a brand new extension to the school, which is under construction alongside the current building.
For every kilowatt of electric you put into the system to run it, you get four times that out
Dr Aled Davies, WDS Environmental
For several months now, a vast, muddy building site has been bustling with activity.
Next to the scaffolding and cement, two large drilling rigs are digging the bore holes. It takes two to three days to make each one.
But why did the school go for such an unusual energy supply?
Staff and pupils at Ysgol y Dderwen pride themselves on being 'green', and headteacher, Huw Watkins told me the children played a significant role in reaching the decision.
"Our eco-committee at the time thought it was very important to build in as many eco-friendly things as possible in the new build," he said.
"One of the things was the ground source heating".
Although projects like this can be costly to install, the school hopes it will help save money in the long term.
Dr Davies said: "Against conventional systems, like oil and gas, where we talk about 95% efficiency, because of the way these operate and the free energy you're collecting from the ground, they're actually 400 to 450% efficient.
"So that means, for every kilowatt of electric you put into the system to run it, you get four times that out."
But this isn't all about saving money.
The pupils believe what they do now, will have a lasting impact on the environment.
In the words of 11-year-old Rachel: "It's good to be eco-friendly to our school because we'll have better turnout in our world".
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