Finding new sources of renewable energy

The continuing search for solutions to reduce our carbon emissions and reliance on fossil fuels often brings up novel ideas from researchers, some more suitable and successful than others. One such recent idea which is providing successful preliminary results comes from researchers at Nottingham Trent University working with renewable energy firm Alkane Energy.

As part of a two year project they have explored the possibility of using water from abandoned mines to heat homes and businesses via a heat pump and through a district heating network.

Using the disused Markham Colliery in North East Derbyshire they established that thermal energy contained in the naturally lukewarm water found in mines can be condensed and used to heat and cool all types of buildings.

Speaking of the findings Professor Amin Al-Habaibeh, of the School of Architecture, Design and the Built Environment, who led the study, said “In a way we may never have previously envisaged, coalmines could once again be used to provide warmth to thousands of homes across the UK. But the key difference between yesteryear and tomorrow is that we now have the ability to harness their energy potential in a completely sustainable way.”

The technology developed for the project was based on a ground source heat pump system which removes water from the mineshaft and pumps it to the surface where the latent heat energy can be extracted using a heat exchanger. The water is run through the heat pump a second time where the energy can be condensed and circulated in a separate central heating system producing a much higher temperature of water than that originally used. The now cooled groundwater is then returned to the mineshaft where it becomes heated again due to the ground heat.

The Coal Authority provided permission to explore a number of disused mines over a 30km squared with the potential to generate enough energy to heat 45,000 homes. At the Markham Colliery, the heat was used at an industrial complex owned by Alkane. The project was funded by Innovate UK and the research findings were presented at the global Applied Energy Conference, in Abu Dhabi, last month.

The project also assessed periods for which renewable energy supplies (primarily from solar and wind) were insufficient for powering the ground source heat pump. Mains electricity was used as an alternative and even with this it was found that the technology was still four times more efficient than a modern gas boiler running at 90% efficiency.

Keith Parker the project director at Alkane Energy concluded “Alkane has traditionally utilised gas contained in disused coal mines to power its core electricity generation business. The utilisation of heat from mine water gives rise to a further opportunity to make use of the mines to provide green, sustainable energy to homes and businesses in the UK.”

It should be the aim of all nations to produce both 100% of electricity and heat via renewable sources. We are however some way off that at present. As shown in recent months renewable energy generation via wind and solar is doing a fine job providing electricity but the next step is heat generation.

The technology for providing heat via renewable sources like that above is still very much in its infancy meaning we are more likely to be years rather than months away from reaching this goal. However wind and solar had to start somewhere and if you had said 10 years ago that these forms of renewable energy would be regularly producing 100% of our electricity demand few would have believed you. However renewable energy is regularly generating 100% of our electricity demand and while heat generation from renewable sources has some catching up to do, innovations and research like the heat from mines project above have put us firmly on the right track. We believe that all of our energy needs, electricity and heat, can be generated from renewable sources and that is why the inventiveness and determination of these researchers and the solution they offer cannot be underestimated.

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