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'Intuitive and straightforward' - How geothermal energy could change how Irish homes are heated

By 2025, a target may be set for how much geothermal energy should contribute to Ireland’s long-term plans to reduce emissions.

Engineers at a geothermal power station in Bavaria, Germany
Engineers at a geothermal power station in Bavaria, Germany
Image: Alamy Stock Photo

GEOTHERMAL ENERGY COULD dramatically change how homes and businesses are heated in Ireland and help the country reach its 2050 climate target if current barriers are overcome.

Scientists say that the energy – which uses hot water that comes from underground to produce heat or electricity – is a secure, accessible and low-carbon source. 

A spokesperson for the Department of the Environment says that by 2025, a target may be set for how much geothermal energy should contribute to Ireland’s long-term plans to reduce greenhouse gas emissions.

The department is due to present a policy statement on the potential for geothermal in Ireland before the end of June, with legislation to be introduced in the Dáil next year.

However, a data gap on temperatures deep underground must be filled to prove to investors that the energy source would be reliable – and attract funding for high upstart costs.

Those key barriers of a lack of data on deep subsurface temperatures and expensive initial costs will need to be addressed – but if they can be, experts say geothermal could provide a reliable and steady source of renewable energy to heat our homes in the coming years.

A reliable source

Compared to wind or solar, which can be affected by the weather, geothermal is a relatively constant source of energy.

It uses different types of systems depending on how deep the earth is drilled into, the shallowest of parts of which are already in use in Ireland in some homes, businesses and local swimming pools.

“It’s a really readily-accessible source of renewable heating that is so intuitive and straightforward that it’s hard to believe it hasn’t been tapped into more so far,” according to Dr Ulrich Ofterdinger of Queen’s University Belfast, an expert in geohydrological systems.

More advanced forms that are still relatively close to the surface could also be significantly expanded in the next ten years.

“They’re not necessarily off-the-shelf: there’s still work to be done in terms of designing and putting the policy and legislation into place in Ireland to make sure the installation is managed properly,” Dr Ofterdinger explained.

“And that they’re not interfering with each other – because you could imagine that you could have quite a few of those in an urban setting and you want to avoid that.

“But it’s something that could be implemented between now and 2030, for example.”

Currently, the most common form of geothermal energy in Ireland comes through heat pumps, which take heat from the ground, amplify it, and use it to heat a building.

Dr Sarah Blake, a Senior Geologist at Geological Survey Ireland, told The Journal that there are “a lot of shallow geothermal installations in the country already and they’re ideal for one-off housing”.

They take quite a low temperature, say between 10 and 15 degrees, [and] it’s very constant year-round. They take that heat from the ground and boost it with a heat pump and this is quite effective for smaller-scale projects.

Although these heat pumps need electricity to work, the amount of heat they can be used to produce is usually around four times greater than the input.

“So, for every electrical unit that’s used for the heat pump, you get four units for heating,” Dr Ofterdinger said.

“There’s a significant saving to be made there and when you consider that maybe the electricity that you’re using for the heat pump could be provided by other renewable sources, like wind or solar, then you have more or less a net zero technology there.”

Slightly deeper versions aren’t yet well-established in Ireland or in the UK, but are common in places like the Netherlands, where geothermal energy is used to produce heat for the horticultural industry.

Even deeper systems that can be used to generate electricity are more established in countries like Iceland that are located at sites of volcanic activity.

the-hague-geothermal-station-the-hague-netherlands-architect-jan-splinter-2012-geothermal-plant-set-in-urban-context-with The Hague Geothermal Station in the Netherlands Source: Alamy Stock Photo

“In Ireland, these latter ones where you go really deep and get electricity and heat out of it, that’s probably the most distant application that I could see maybe only happening in ten to twenty years or so,” Dr Ofterdinger said.

At the GSI, whose research is used by the Department of the Environment to form policy, Dr Blake said that Ireland is using the Netherlands, France and Belgium as examples.

“The likes of Iceland or the Azores or New Zealand where there are volcanic situations – these are places where you get very high temperatures very close to the surface.

“In Ireland, as in those European examples, we have to drill deeper to get the temperatures that we need for things like district heating and industrial applications.”

Data gap

One barrier to developing geothermal energy is a lack of information in Ireland about temperatures deep underground.

“We still don’t have a lot of deep subsurface data for Ireland and this is mainly because we never had an onshore oil and gas boom,” Dr Blake explained.

Other places, starting in the 60s and 70s all over Europe, had a lot of onshore drilling, and the legacy data from that drilling means that they are quite certain about their subsurface, whereas we’re not.

“We need the deep data to be able to fully understand the economic picture.”

That data is important from a scientific perspective, but also as evidence to show financiers that it’s a safe investment.

“Drilling for geothermal is still quite a risky prospect financially in Ireland because you don’t know what you’re going to get. As geologists, we deal with uncertainty everyday, but there’s only so much of that that investors can take,” Dr Blake said.

“We recognise that we need to derisk the subsurface. A key step in finding out more about the resource but also on the road to using it is finding out more about the deep subsurface and that will only happen really if we do deep geophysics and deep drilling.”

A spokesperson for the Department of the Environment told The Journal that we “need more information on the deep subsurface to promote investment in this area”.

While we’re not, in this policy statement, setting out a new research programme to get that data, we’re signalling that that’s something that will need to be done to promote geothermal energy into the future.

The initial costs of drilling and setting up a geothermal system are also steep.

“The main barrier to geothermal development is the cost. [For] these deep boreholes for kilometres, it’s going to cost millions of euro,” Dr Blake said.

Countries where geothermal has taken off, like Germany and the Netherlands, have offered policy supports and financial incentives to absorb some risk from developers.

It’s something that might be looked at in Ireland “down the line”, the department spokesperson said.

“In other European countries, they did have financial incentives in place, so that’s something to be looked at,” they said.

“It’s not something we have the data or figures at the moment to say we’re going to introduce a financial incentive for geothermal projects, but definitely it’s something to be looked at down the line. But there’s been no policy decision on any of that as of yet.”

The policy statement due to be presented to the government, which is currently open for public consultation, includes a licensing system for exploring and harnessing geothermal energy.

“If you’re investing a lot of money in drilling down into a source of heat, investors aren’t going to back that unless they’re sure that they’re going to have access to that heat for their project over the term it will take for that project to return its investment,” the spokesperson said.

“You don’t want some other project coming next door to yours and using the same heat resource.”

Climate goals

In Northern Ireland, where Dr Ofterdinger is based, researchers and corporations have launched projects in recent months to build momentum on geothermal.

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A new energy strategy from NI’s Department for the Economy published in December emphasised the future role of geothermal as a renewable and reliable source.

“When you look at the energy strategy and the roadmap that in Northern Ireland has been published, there is an appetite for driving geothermal installations in the roadmap to 2030 towards net zero,”  Dr Ofterdinger said.

“That’s one element of decarbonising heating and it’s being taken quite seriously. The departments are looking for demonstrated projects to get off the ground with feasibility studies in this year for example.

“That’s in their action plan for 2022, to commence with some demonstrated projects.”

In the Republic, scientists and policymakers agree that geothermal is an energy source with major potential as part of decarbonisation efforts.

The Climate Act passed in 2021 committed Ireland to reaching net-zero greenhouse gas emissions by 2050 and cutting emissions in half by 2030.

Under the latest Climate Action Plan, renewable sources should generate up to 80% of electricity by 2030.

Geothermal energy “has great potential to decarbonise heating in particular, not to mention electricity maybe at some point in the future”, Dr Blake said.

And it could be used across the country; there are some places where scientists “expect the rocks to be hotter”, but overall, it’s not limited by location.

Geothermal is local. It’s under your house, it’s under your business, so it’s a secure supply. It’s completely renewable. I think that’s a major benefit.

But there’s still much to be done before significantly ramping up its use.

“In terms of a timeline, we’re going to government with a final policy statement following the public consultation exercise by the end of June this year and then we can start preparing the legislation to introduce the regulatory framework,” the department spokesperson said.

“We would hope to introduce that some time the following year depending on Dáil timetables and everything. In tandem with that we’d start the work on how you compare geothermal to other sources of renewable energy and what the economics of geothermal energy projects are.

“The target deadlines [for emissions reductions] are 2030 and 2050. There isn’t a target at the moment for geothermal to provide ‘X’ amount of heat or to reduce our carbon emissions by ‘X’ amount. We’d hope by 2030 or 2050 we’d be making a contribution. It may be by 2025 we’d have a target that we could aim towards for 2030 or 2050.”

About the author:

Lauren Boland

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