What’s The Potential Of Geothermal Energy For Irish Agriculture?

Could the required energy comes from under our feet.

It’s more commonly associated with Iceland, the land of fire and ice, but advances in technology mean that geothermal energy can now be used in non-volcanic regions, such as Ireland.

A new Government report suggests geothermal could have significant potential for Irish farms, in processes such as heating and cooling buildings, and possibly even to produce electricity.

“Geothermal energy” is the term used to describe the heat beneath the surface of solid earth. It can be stored heat from the sun, or heat from the earth’s core.

This type of energy has been used for a long time in volcanic regions, such as Iceland, Italy, and New Zealand.

However, recent developments have opened up the possibility for the technology to also be used in non-volcanic parts of the world, for example, its application for horticultural growing in the Netherlands.

The technology could be revolutionary for sectors such as dairy, which uses large amounts of energy to heat and cool milk through the production process, and also horticulture.

Geysir sometimes known as The Great Geysir, is a geyser in southwestern Iceland

The geothermal potential of Ireland is not yet fully understood, with the Government’s draft policy statement on geothermal energy for a circular economy saying more research is needed.

However, it could have significant environmental gains for Irish farming and the agri-food sector should it be found to be viable here.

Minister for the Environment, Climate and Communications Eamon Ryan said geothermal energy is not only renewable, it is also secure, reliable, and local and has the potential to play a “significant” role in Ireland’s transition to a carbon-neutral and circular economy.

Very low enthalpy (the measure of heat content) “shallow” geothermal resources exist all over the country within a few hundred metres of the surface and can be used alongside a ground-source heat pump to heat and cool buildings.

Enthalpy can be split into low, mid, or high categories.

Beneath Ireland’s surface, low (30C to 80C) to mid (80C to 120C) enthalpy resources exist, but require deep drilling — up to 5km of drilling may be required for the higher end of the mid category.

It might not be as hot as the geezers of Iceland, but even our somewhat cooler geothermal resources could have significant potential for farming.

Dairy Processing

Overseas, shallow geothermal resources have been used for aquaculture, such as in Huka Prawn Park, Taupo, New Zealand, and for soil warming.

Low enthalpy geothermal heating can be used effectively in traditionally energy-intensive horticultural operations, such as heating greenhouses to grow fruit, vegetables, and flowers, like in Slovenia and the Netherlands.

Low and mid enthalpy geothermal resources can also be used to dry agricultural products, such as tomatoes, chillies, rice, cotton, and timber.

The draft policy statement on geothermal energy for a circular economy proposes that Irish geothermal resources could be used to increase the proportion of energy coming from renewable sources in agriculture, in particular, increasing the share of renewable heat in dairy farming.

Dairy processing requires large amounts of energy, and Teagasc notes that milk cooling, water heating, and vacuum pumps account for the biggest proportion of energy use on Irish dairy farms.

Milk cooling is the biggest driver of energy consumption on dairy farms, using 31% of the total amount, followed by water heating at 23% and the milking machine at 20%.

Geothermal energy has been successfully used for processes such as milk pasteurisation in Oregon and cheese maturation and storage in Italy.

With this potential in mind, Mr Ryan has launched a public consultation on the draft policy statement, open until March 1, to gather the views of the public and key stakeholders.

Mr Ryan has described this draft as an “important step in addressing the barriers to the development of geothermal energy in Ireland”.

The final policy statement will outline the regulatory framework and be a base for further work in data collection on Ireland’s geothermal resources.

According to the Sustainable Energy Authority of Ireland, 38% of all energy consumption in Ireland is used for heat.

Oil, gas, and solid fuels are still the primary means for heat generation.

In 2020, the agriculture and fisheries sector accounted for 2% of the total share of energy consumption in Ireland.

This subsector’s share of energy for heat made up 4% of the total in 2020, while making up 2% of the demand for energy for electricity.

The last two decades have seen Ireland shift from an oil dominance for heating to near parity between oil and gas for heat supply.

The largest and most consistent reduction in oil use for heat has come from the industry sector, with the agriculture and services sectors seeing smaller reductions.

According to Teagasc, farm businesses are under “increasing pressure” to become more energy efficient.

Barry Caslin, Teagasc energy and rural development specialist, said that, for these units, both air and ground-source heat pumps can be a good source of heat, and also for some horticultural operations.

However, some agricultural sectors will have more needs than others.

Lee Carroll, head of the Sustainable Energy Authority of Ireland’s energy statistics team, said that cattle and sheep farms “have little to no heating demand”.

“Dairy farms require energy for heating water in milking parlours and to cool and refrigerate milk,” said Mr Carroll.

“However, the amounts per farm are relatively small. The main requirements for heating in agriculture are likely to be in the large poultry and pig producers.”

Case Study:

What lies beneath is ‘part of the solution’ for New Zealand dairy

Established in 2011 by a group of Maori organisations in New Zealand’s North Island, Miraka dairy factory is located within the Taupo Volcanic Zone, an area of geothermal activity.

This extends from the active volcanoes of the central North Island to the Pacific Ocean, encompassing Lake Taupo and Rotorua.

The factory was built on a geothermal field, adjacent to a geothermal power station.

Geothermal energy was a key part of the founders’ vision — to build a business based on the Maori concept of “Kaitiakitanga”, which means guardianship of the environment, a spokesperson for Miraka explained to the Irish Examiner.

In the same area, there is a cluster of geothermal-related activities, including the dairy plant, power station, heated glasshouse, and a hydrogen generation plant, demonstrating the vast range of potential uses.

The dairy factory, which is supplied by around 100 local farms, processes 300m litres of milk a year, producing about 35,000Mt of dairy powders, and 60m litres of UHT milk.

The facility uses geothermal in two ways. Firstly, geothermal steam is used to produce clean steam through a heat exchanger. This steam is used in heating throughout the plant. Secondly, the dairy factory draws electricity from the geothermal power station. This is used to power the plant.

In 2019/2020, the dairy factory used 273 terajoules of energy, 95% of which was from renewable geothermal energy.

Miraka estimates that its manufacturing carbon emissions, per megatonne of powder product, would be about 15 times higher if it used a combination of a coal-fired boiler and national grid electricity to operate the plant.

In terms of the final consumer product, Miraka said that on-farm emissions still count for the vast majority of the carbon footprint of the dairy product.

However, its geothermal manufacturing, it feels, provides a strong sustainable foundation from which it intends to build a low-carbon food production system, extending from the farm to the consumer.

In Ireland, the geological features are very different.

However, more than 25% of the EU population lives in areas directly suitable for geothermal district heating.

Luca Guglielmetti, senior researcher at the University of Geneva and part-time associate to the International Geothermal Association explained that there has been “a wave of geothermal developments” focusing on heating and cooling in non-volcanic regions in the last 10 years or so.

“There is a lot of potential for geothermal development because non-volcanic regions are the areas where there are the highest population densities and therefore, energy demand,” he explained.

“Where you have lots of people, you also have lots of people eating, and food production is responsible for about 30% of global emissions and this is huge.

“One of the main demands in agri-business is heating and cooling; you can see that there is a match between the configuration of the global energy system and what the food sector needs.”

Mr Guglielmetti emphasised geothermal is “not the solution, it is part of the solution”.

“To decarbonise the sector, specifically in areas where it’s tricky or too expensive to produce electricity with geothermal, you should focus on the heating and cooling, and combine it with other renewables.

“In the agriculture sector, biomass can play a big role in producing power. It’s great to integrate geothermal in agriculture but at the same time you have to combine it with other renewables to make it fully sustainable.”

Mr Guglielmetti said that there is a “lack of education about geothermal”, and that one of the blockers to integrating it is that capital expenditures are relatively high.

“A farmer who already has an entire production framework implemented, and that works, and its cost fluctuates only because of the oil and gas, to integrate geothermal and other renewables they have to make also a technical transition,” he said. “This is not something that you do overnight, it costs a lot, it’s difficult.

“To boost this in countries that don’t have geothermal in the agri-business, we need pilots.

“And pilots mean small-scale installations, different types of food products, and projects that cover the entire process from the resource assessment to the fork.”

In its 2015 report on the use of geothermal energy in agriculture, the Food and Agriculture Organization (FAO) of the UN noted that start-up costs remain the main barrier to developing geothermal energy uses on a larger scale, especially in developing countries.

This makes it “more necessary for governments to take a leading role in attracting investment and creating policy environments that support the sector”, according to the FAO.

The report notes that geothermal energy is already used in the food and agriculture industries in many countries around the world – but that progress in the area of geothermal development has been slow in most.

(Source – Irish Examiner – Farming – Kathleen O Sullivan – 12/01/2022)

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