‘Energy from the ground has always been around’

In Ireland, the use of geothermal energy resources is limited, mainly confined to small-scale individual heating projects, such as in individual dwellings or industrial heating applications.

However, according to experts, there are a number of advantages to using geothermal energy in its primary form — heat — in the agri-food sector.

According to the International Renewable Energy Agency, using this for greenhouses or for food drying and processing has the potential to increase food availability, reduce dependency on fossil fuels, protect against price volatility, diminish harmful emissions from the sector, and reduce food waste.

The Geothermal Association of Ireland has said geothermal energy and the use of heat pumps is “very efficient”.

The system can be more expensive to install than traditional gas or oil-fired systems, but has “very low running costs” from thereon, meaning that while it may require grants or loans to get started, it could pay dividends in the long run.

Costs for geothermal systems can vary greatly. 

However, a ground-source heat pump is likely to cost upwards of €12,000, depending on size, hot water storage, and ground loop system. The largest industrial set-ups, more suited for the processing sector, can cost up to €1m.

Read More

What's the potential of geothermal energy for Irish agriculture?

Niall McCormack, chairman of the association explained: “It is used around the world in environments not dissimilar to Ireland for lots of different things, including in the agri-food sector.

“There are three things you’re solving for: Sustainability, energy security, and energy affordability.

“One of the reasons geothermal is attractive is because it’s sustainable and secure, and what’s happening over the last few years is that it has become economically competitive.

“You see enormous amounts of deployments in places like Sweden where the ratio of electricity price to natural gas price is low.

If you’re somebody who’s looking out there for 20 to 30 years time, this is a strong economic system, he says.

Mr McCormack said that in Ireland, there has been “very little driver to move away from the status quo” and move towards the use of geothermal energy over the last number of years.

However, there are now “multiple drivers”: Gas price volatility, gas security of supply, and sustainability — the “three pressures coming onto industry and agriculture”.

“Heating and cooling in the agri-food sector is an area where it’s easy to decarbonise,” Mr McCormack said.

“There are other elements that are quite hard to decarbonise and to reduce greenhouse gas emissions, but this is one where there’s actually no impediment to doing that.

“The technology works at pretty much every scale, so it’s not scale-dependent.

“You can go from your house which is around 10kW, to megawatts which is a large processing plant.”

As far back as the Roman times

Vice-chairman of the association, Ric Pasquali, added that all the technology to install a geothermal system is “off the shelf”.

“We’re not talking about stuff that is under research or that’s under development,” he said.

“Geothermal has been used as far back as the Roman times.

“Energy from the ground has always been around and it has been used more in some places than in others.”

Mr McCormack explains it simply: When you go down into the earth, it gets hotter.

“There’s two places the heat comes from — one is from the centre of the earth, it’s cooling down very slowly over billions of years. The other is that the rocks themselves generate some heat.

“As you go down, on average, it’s between 25C and 35C per kilometre. Across the world, however, there are some places where it’s a lot hotter and some places where it’s a lot colder.

“Ireland is about average across the island, give or take.”

Geothermal energy involves accessing this heat and using it.

There are two ways in which it can be accessed.

In an open-loop system, heat is collected from water underground. Closed systems take heat directly from the soil and rocks in the subsurface.

“We drill holes. If you want to go shallow, dig a ditch, put some pipes down, and bury it. That’s normally deployed for smaller-scale deployments. It’s basically like solar panels but you’re using the ground instead of panels on a roof,” said Mr Pasquali.

“When you want more energy, you normally drill a bit deeper. You’re drilling a well down and you’re putting a pipe in the well and you’re circling water through that pipe and you’re collecting the heat from the system.

“At the surface, you have a cool piece of kit, called a heat pump. Heat pumps are the magic that then takes the 15C and allows you to convert that into 60C to 80C.

“The deeper you go, the hotter it gets.”

Accessing energy at a later stage

Mr Pasquali explained that harnessing energy into heat can also deliver on cooling needs simultaneously.

“This is one of the massive advantages of geothermal - it’s not either this or that,” he said.

“You could be taking 12C water into a heat pump to produce heat, but at the same time take the same water at the back end of that heat pump to cool something else.

“The other aspect that we can’t forget is that you can also do energy storage.

“You can take energy from the surface in the form of heat and store it in the ground for a period of time and then access that energy at a later stage for something else.

“A really simple example would be if you were cooling a building in the summer months, you take the heat from that building and you put it in the ground, and then you reverse the cycle in the winter, with or without a heat pump there’s a number of ways of doing it — but you can take that energy back into the building when the cycle changes or you can do it simultaneously.”

In some places around the world — not many in Ireland — Mr McCormack said that it “can get hot enough quickly enough that you can produce electricity from it”.

However, “realistically, you’d normally need the temperature to be over 150C for the economics”.

Mr McCormack added that going forward, how licensing of geothermal resources is done is “incredibly important for the end-user so that people can develop the heat resources they have around their farms and facilities”.

Substantial shift in policy

Widespread adoption and addition of geothermal energy to the national energy mix would require a “substantial shift” in policy and funding, according to a recent report.

Whilst work is currently underway to develop geothermal legislation at national level, the Irish geothermal sector “remains in its infancy and will need increased support from policymakers to encourage its development”.

During his time as a researcher in residence with the Oireachtas, Dr Nicholas Vafeas of University College Dublin examined the potential of geothermal energy in Ireland and the policies surrounding its development.

Dr Vafeas has said that Ireland’s focus thus far has been largely placed on renewable electricity, driven by binding targets at national and EU level.

This has now led to a lag in progress for renewable heat and an overreliance on wind energy to meet renewable energy commitments.

According to his Spotlight report, which forms part of the Science Foundation Ireland Public Service Fellowship, binding energy targets and developmental funding schemes incentivise the need for a renewable energy system that is inclusive of geothermal resources.

The report noted that despite the Climate Action Plan calling for development of a policy and regulatory framework for geothermal energy in Ireland, “as of yet, a clear policy for any real utilisation of geothermal energy remains absent in legislation”. There are currently no binding targets committed towards renewable heat.

Although legislation around exploration and regulation of geothermal energy in Ireland is absent, Geological Survey Ireland found through its assessment of geothermal energy for district heating that in 2018, there was an estimated 1,805 domestic ground-source heat pump installations in Ireland, and in addition, at least 87 commercial installations.

Despite the increasing consensus for cleaner energy use in Ireland, “encouraged by the Government and the EU, as well as general support for renewable energy in rural Ireland, the use of oil and peat for heat generation predominates outside of major city centres”.

“This is due to an overall lack of natural gas network infrastructure that has left rural Ireland with few alternatives to conventional oil heaters,” the report said. This is amidst the Government commitment outlined in the Climate Action Plan 2021 to “effectively ban” the installation of fossil fuel boilers in new homes by the end of 2023.

The author noted that there are a “number of barriers that must be addressed for the effective introduction of geothermal energy in Ireland”. These are named as: classifying the resource; planning and regulation around its use; mitigating risk; and addressing geological uncertainty.

Ownership of Ireland’s geothermal resources has not yet been defined, the report noted, but “could be based on existing models of private, public or mixed ownership”.

Geothermal projects also need “significantly greater upfront capital expenditure compared to most other renewable technologies of similar capacity”.

“The ability to raise funds needed for the development of an effective geothermal project is inherently linked to the risks associated with a failed installation,” the report said. The drilling phase of the “average shallow geothermal system” can consume up to 40% of the overall cost.

However, precise cost estimation for shallow geothermal systems can be difficult as these costs can be “highly variable, depending on a variety of factors”. These can include: local geology; drilling depth; installation size; and heating requirements. For deeper geothermal projects, the costs rise.

“In addition to the high costs, the drilling phase also contains the lowest guarantee of success,” the author said in his report.

“If a resource area that has been drilled for exploration is found to be unsuitable for a geothermal installation/development, the invested capital is lost.

"Unquantified geological risk means that investors may be more reluctant to contribute to drilling costs as they may not recover their investment if the project were to fail.

“A national Irish database containing all available information on the subsurface generated from construction, water wells, mineral and hydrocarbons exploration and other geological activities could leverage existing information to reduce costs and geological uncertainty.”

The author said that clear and decisive policies for geothermal resources would enable "successful adoption and progressive investment in this proven energy sector".

Read More

What's the potential of geothermal energy for Irish agriculture?