The development of a biomethane industry using grass silage and animal slurry is projected to increase agricultural sector incomes by 1.2% to 1.3% or €49m to €53m.

This comes as Teagasc publishes a landmark research report assessing the potential for agriculture-based anaerobic digestion (AD) at a national level.

Teagasc has also projected that this approach will reduce agricultural greenhouse gas (GHG) emissions by 2.3% compared with a scenario where such feedstock use does not occur.

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The report, produced under the FLEET Project [Farm Level Economic, Environmental and Transport Modelling of Alternative Feedstocks for Regional Anaerobic Digestion] delivers the most comprehensive assessment to date of the economic viability, environmental impact and logistical challenges involved in using grass and animal waste as a feedstock for biomethane production at a national scale.

Alternative

The report finds that while supplying grass silage to AD plants can be a competitive alternative to traditional cattle and sheep enterprises, profitability varies significantly by farm and depends heavily on the price paid to farmers for silage.

This research project was jointly funded by the Sustainable Energy Authority of Ireland (SEAI) and Gas Networks Ireland (GNI) through the SEAI national energy RD&D programme.

A survey conducted as part of the study revealed a strong willingness among farmers to supply 175,000ha of silage, well above the 110,000ha to 130,000ha estimated to be required to meet Ireland’s 5.7 terra-watt hour (TWh) biomethane production target for 2030.

The study also highlights significant environmental benefits to increased AD adoption.

Slurry-based AD feedstock systems were found to deliver emissions reductions as high as 11%/ha

Grass-based AD feedstock systems could reduce farm-level GHG emissions by 50% to 98%/ha on participating farms, driven largely by reductions in livestock numbers.

Slurry-based AD feedstock systems were found to deliver emissions reductions as high as 11%/ha.

A spatial transport analysis included in the study using national road network data indicates that, under non-constrained typical conditions, most AD feedstocks could be sourced within 10km of potential AD plant locations.

Under more constrained conditions, this range could extend to 15km or more, with implications for both the associated cost and the emissions reductions achieved.

With the publication of the final FLEET report, Teagasc and project partners will continue to advance research in this area.

Future work will assess additional feedstocks, explore alternative business models and update economic and environmental analyses in line with evolving market and policy conditions.