Biogas plants essential to the future circular economy, says UCC Professor

17 September 2018
By Mary Bermingham
mary@TheCork.ie

A leading Irish environmental engineer has called for decarbonisation of Ireland’s gas system in order to achieve the circular economy objectives laid out in the government’s €21.8 billion National Development Plan.

Speaking at the SEAI/ International Energy Agency Bioenergy Symposium on “Anaerobic Digestion in the Circular Economy” recently in UCC, Professor Jerry Murphy described a decarbonised gas system as the ‘epitome of the circular economy’.

“Biogas plants cannot be directly compared to other renewable energy sources like wind turbines, which produce electricity,” explained Prof Murphy, Director of the SFI MaREI Centre headquartered at the UCC Environmental Research Institute and Leader of the International Energy Agency Biogas Task. “There are so many more advantages to a biogas system – from waste treatment, production of bio-fertiliser, generation of a renewable energy suitable for transport, heating or electricity, improved water quality and provision of jobs in rural communities. It is the full package.”

Biogas plants rely on anaerobic digestion, a fermentation process in a closed vessel where waste such as manure, food and sewage are digested by microbes, producing methane gas (biogas), and converting the waste into biofertiliser.  For farmers who opt to build these plants to deal with their manure, the biofertiliser can be then spread directly onto fields, reducing bills (and emissions) from fossil fertilisers.

The biogas itself may be used as a fuel and, as it is completely interchangeable with natural gas. In 2018, Gas Networks Ireland will introduce biogas onto the Irish gas network for the first time and they have a target of at least 20% of all gas used in Ireland to be renewable (and decarbonised) by 2030. A significant aspect of this rollout will take place in the transport sector under the €25 million EU-funded Causeway project which aims to provide a sustainable, clean alternative to diesel for Ireland’s transport operators.

Industry in Ireland is leading the way in embracing this new source of green energy through collaboration with Irish farmers. Diageo aims to derive all of its electrical energy from renewable sources by 2030. It intends to source decarbonised biogas from producers such as the Green Generation biogas plant based in the Costello pig farm in Nurney, Co. Kildare.  Dairygold’s Mitchelstown complex is home to the world’s largest above-ground anaerobic digester which produces biogas from dairy industry waste water to fuel its production needs.

“The benefits are multi-faceted,” emphasised Prof Murphy, “Biogas plants produce a dual climate effect through reduction of methane emissions by using closed vessels and by producing a biofuel alternative to fossil fuels. Biogas is a ‘green’ sustainable energy vector and has a significant role in shifting to a sustainable decarbonised society. The future of the biogas facility is a bio-factory where value is created from previously wasted materials; this ensures sustainability of the environment and potential for financial gain for the local community. The biogas plant is the hub in the future circular economy.”

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