One of my predictions for 2026 is that Ireland will get on track to scale up generation of the green gas biomethane using agricultural and food wastes. A tipping point has finally arrived.
For a country with a large agricultural sector, where most farmers and food processors want to do the right thing environmentally, it’s a no-brainer. It also comes with a sweetener – it can boost farm incomes.
The infamous “cash-for-ash” scandal in the North, an open-ended renewable heat scheme which cost taxpayers some £500 million, probably suppressed appetite down South for a State-led scheme supporting biomethane for too long.
Biomethane generation is possible with incinerators and municipal wastes, and is considered carbon-neutral. Produced by upgrading biogas from organic farm waste, food and sewage through anaerobic digestion plants (ADs), it replaces fossil gas (promoted as natural gas) in heating, transport and industry.
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Yet biomethane generation can be controversial, with “rural myths” about it fuelling opposition in some areas, amid claims that government policy is only going to favour large energy companies over struggling farmers.
When an AD is well-run in an industrial setting, it ticks a lot of boxes. Having observed their operation in Ireland and abroad, they are surprisingly unsmelly, given the feedstocks used. They come with benefits beyond helping to decarbonise a farming sector responsible for 37 per cent of Irish carbon emissions. An AD is a good example of how a circular economy works.
The more sophisticated ADs process agricultural residues into biomethane; they create a byproduct, biogenic CO², which can be monetised and used in industry, and also convert the remains (digestate) into fertiliser. Switching from spreading raw slurry on land to using digestate cuts nitrate emissions significantly, while also reducing the soil acidification and groundwater eutrophication that are all too often evident in Irish rivers and lakes.
Using energy crops for the purpose, such as grass and maize, is an option. For farmers with less-intensive operations, this could ensure more consistent income. Potential downsides include competition with food crops for land, excessive chemical fertiliser use, and environmental impacts arising from monoculture.
Biomethane has been proposed to reduce data centre emissions but, as energy specialist Prof Hannah Daly warns, the scale of data centre demand would exceed sustainable production and risks diverting resources from other sectors.
Government strategy seeks to replace about 10 per cent of Ireland’s fossil gas demand with renewable, locally produced gas, and to support construction of more than 150 ADs by 2030.
A modest capital grant scheme totalling €40 million supports developers. Industry sources say up to 25 ADs are ready to go into construction or the planning system, with more likely to have planning approval sought later this year.
The right signals are being sent to investors, including the EU ruling that soy biofuel will no longer count towards renewable targets, as it causes deforestation. Europe is getting its act together on sustainability certification, clamping down on dodgy biofuel imports.
Greengate Biogas, an Irish offshoot of Copenhagen Infrastructure Partners (CIP), is intent on building large-scale biomethane plants, starting with the country’s largest in Powerstown, Co Carlow, currently in planning and designed to process 700,000 tonnes of slurry into biomethane, biogenic CO² and fertiliser.
This would provide sustainable energy equivalent to the heat demand of about 22,700 households. The company is planning to build seven in total, which would add up to ability to deliver a third of that national 2030 target of about 10 per cent of Ireland’s fossil gas demand.
Larger facilities such as this are new to Ireland, but it is understood that Greengate Biogas has received favourable reaction from the Irish authorities, including Minister for Environment, Climate and Energy Darragh O’Brien. Likewise, the larger food co-ops have indicated willingness to build at this scale and to form partnerships with developers.
Much of Europe has smaller on-farm ADs that can have odour problems, yet with the right scale and treatment of manure and odour, as well as the correct location, there should not be a problem with them.
Some developers believe biomethane plants should be classified as strategic infrastructure development to ensure a clear planning route through An Coimisiún Pleanála. Clarity on “end-of-waste” classification of digestate – allowing it to be treated as a raw material rather than something to be disposed of – and greater incentives to reduce agricultural emissions would also be helpful, they say. Meanwhile, the Government’s new “renewable heat obligation” helps create bankability for projects by requiring fossil gas to contain a proportion of biogas.
Biomethane production in Denmark has grown rapidly, with renewable gas now accounting for more than 40 per cent of total gas consumption in the grid. The target is 100 per cent renewable gas by 2030–2035. That kind of ambition heightens energy security, helps wean users off fossil fuels and avoids costly fuel imports. Ireland should be equally ambitious.
Kevin O’Sullivan is an environmental consultant
