What do slurry, anaerobic digestion (AD) and boiling a kettle have in common?
In Ireland – not a lot now – but fast forward to the end of the decade and the answer could be… Irish farms.
To get there however it could take €1 billion of capital funding and a major leap into the unknown for some farmers to embrace new anaerobic digestion (AD) opportunities.
AD and emissions targets
In the updated Climate Action Plan recently published by the Irish government, there is a strong emphasis on the role AD could play when it comes to the roadmap to achieving the emissions reduction targets set for the agriculture sector in Ireland.
AD can capture the methane gases produced by decomposing organic waste such as slurry and crop residue including grass silage, and transform it into renewable energy in the form of biogas and also organic fertiliser.
Upgrading the biogas then delivers biomethane which is an in-demand renewable natural gas.
In the latest Climate Action Plan the government has detailed its commitment to delivering “up to 5.7 terewatt hours (TWh) of indigenously produced biomethane, based on agricultural feedstocks”.
According to the plan, the Department of Agriculture, Food and the Marine (DAFM) and the Department of the Environment, Climate and Communications (DECC) is currently developing a National Biomethane Strategy.
It believes this “will provide both a diversification opportunity for farmers and a land-use alternative to livestock production”.
But there is a long way to go between the government’s ambition and being able to boil a kettle thanks to the energy generated on an Irish farm.
There are currently an estimated 17,500 AD plants across Europe and around 642 in the UK including approximately 60 plants in Northern Ireland.
Ireland may just be embarking on its AD journey but there is well-established evidence on the role that AD systems can play in producing renewable natural gas.
Turning cowpats into power
Arla Foods, the fifth largest dairy company and the UK’s biggest dairy cooperative is keen to highlight how AD is “turning cow pats into power” for its business operations.
It originally launched a trial in 2020 in the UK which involved a herd of around 500 cows which produced 190t of manure a week.
This manure was despatched to the nearest AD plant where it was broken down into various components including biomethane.
The trial produced 27,000kg of biofuel – enough to power two trucks and convinced the co-op that this represented a way of “making dairy farms more sustainable for the future”.
Following the success of this trial, Arla put seven biogas-fuelled trucks on the road.
According to the co-op this has cut emissions from its vehicles by 80% and also represents a “win for our farmers, as a by-product of AD is a natural fertiliser, that can reduce on farm emissions”.
It is currently campaigning to persuade the UK government to tap into what it believes is “a major unused source of energy from farms and the wider food supply chain”.
According to Arla “one bucket of poo” can power 758 kettles to make 4,548 cups of tea or provide power to watch 948 hours of Netflix shows.
James Pirie who is vice-president of UK logistics for Arla said the company believes that “poo power is a viable and reliable source of power” and has called on the UK Government to undertake a major investment programme in AD infrastructure.
Biomethane ambitions
On this side of the Irish sea, the not-for-profit industry group, Renewable Gas Forum Ireland (RGFI) believes there is significant potential for Ireland “to be a leader in renewable gas (biomethane) production, primarily due to our grass-based agriculture”.
The National Heat Study published earlier this year identified biomethane as a “competitive, cost-efficient path” to help Ireland achieve its climate ambitions and as “direct replacement for natural gas”.
The Irish Strategic Investment Fund, which is managed and controlled by the National Treasury Management Agency, is developing a dedicated Biomethane Fund of €200 million.
The RGFI also wants the government to provide up to €100 million in capital funding up to 2025 to support the development of 20 AD biomethane plants.
Climate Action Plan
The government has acknowledged in its Climate Action Plan that getting an AD/biomethane industry up and running “will require intervention in order to build out the infrastructure required to meet up to 5.7 TWh by 2030”.
The Climate Action Plan outlines “delivering on such scale requires in the region of 150 to 200 AD plants. DAFM in partnership with DECC will assess available financial opportunities and mobilise funds where available”.
“This renewable fuel will be essential to decarbonising other sectors of the economy, such as high temperature industrial heat needs in manufacturing processes.”
According to PJ McCarthy, chief executive of RGFI, a scalable and sustainable indigenous AD biomethane industry could deliver significant environmental, social and economic benefits, not only for farmers, but also to the economy as a whole.
“What is not fully appreciated or understood is that AD biomethane will be your central enabler for the bioeconomy to develop at scale here and how that will factor into reaching emissions targets and climate solutions,” he said.
“What is will also mean then is that there are other bioproducts where we can pursue other opportunities e.g., bio-actives, bio-stimulants, biogenic CO2 and they will all contribute significantly to reducing emissions and contributing towards the targets.
“Also when you consider the use of biomethane in the HGV [heavy goods vehicles] sector, that shows what an appropriate and economic use biomethane can be for transport – where your EV [electric vehicle] equivalent or hydrogen equivalent is not economically viable for the HGV sector”.
He said the RGFI is currently in discussions with a number of logistics companies in relation to biomethane opportunities. Many of them, he said, are an integral part of food production in Ireland particularly in relation to the route from farm to factory and further on to processing and then export.
McCarthy believes that Ireland now needs to look at what is the most economical use of energy, particularly with the ongoing European energy crisis.
“We need to fully understand as a nation and as Europeans, we need a fully integrated energy system and applying the renewable energies that we have in the best way possible,” he said.
“We have developed a business case which has farmers absolutely central to the whole equation – the opportunity is there and it really is for them to explore it now, it is a diverse income from what they are currently doing, it complements every farming discipline and provides them certainty. If farmers make the move towards AD biomethane there are multiple opportunities for additional revenue streams.
“AD biomethane can give farmers a sustainable, diverse income; there is a guaranteed market for biomethane and there are a number of routes to market,” McCarthy added.