Bio-digestion is a process system in which organic materials such as animal slurry, food waste, and high energy crops such as maize silage, are heated up and broken down in the absence of oxygen to produce a mixture of gases including methane, carbon dioxide and other miscellaneous gases when combined together form ‘biogas’. The methane gas from this process can be further filtered down and separated leaving a product of just methane gas called ‘biomethane’.
While the uptake of anaerobic digesters in European countries has been high and is now almost a standard practice for utilising animal waste, Ireland has been on the backfoot in getting this technology up and running.
The European Biogas Association (EBA) highlights how the biogas and biomethane industry are replacing fossil fuels, storing carbon in soils, producing green fertilisers, enabling carbon re-use which is ultimately reducing greenhouse gas emissions and paving the way to a negative carbon footprint.
Anaerobic digestion (AD) has a great potential to become a significant source of income for the farmer. Furthermore, it’s by-product digestate is a good, more natural fertiliser for use on the farm. With higher levels of readily available Nitrogen compared to raw slurry it can minimise the costs and use of synthetic fertilisers for the farmer all the while aiding in the reduction of our carbon footprint.
In addition to this, a large quantity of heat is produced by an AD which can be used on farms for the heating of water in milking parlour facilities and similar operations. However, as it stands the lack of funding and government incentive is the main reason for the slow progression of this industry. With such AD plants requiring a multi-million euro investment, it requires great financial aid and support to get these plants up and running. Therefore, it does not make it a simple task to go set one up.
As mentioned, biomethane is purified biogas with the end product being methane gas. This is a great substitute for natural gas which is being used in homes and businesses across the country. The Department of the Environment, Climate and Communications stated that in 2019, 53% of Ireland's natural gas was imported from the UK. However, with the eventual depletion of the Corrib gas field, this figure is expected to be over 90% by 2030.
With Irish agricultural emissions hovering around the 30% mark, Ireland's Climate Action Plan along with the EU Green Deal suspects that there is a lot that can be done in utilising the renewable energy sector to not only reduce overall agricultural emissions but produce a sustainable product in return.
According to the European Commission, due to Ireland's agricultural industry and its economy largely based around it, we have the highest potential for renewable gas production per capita in Europe, with a potential of 13 Twh (terawatt hours) achievable by 2030. Gas Networks Ireland has put a plan in place to try and achieve 11.6 Twh of renewable gas by 2030 through AD but time will tell whether this will be achieved or not.
With the advantages of AD so significant to the environment, farmer, household and government, it will be of the utmost importance that not only farmers but most importantly government bodies such as Gas Networks Ireland and the Department of the Environment, Climate and Communications work together to come to a solution and incentivise such an initiative in order to kickstart the Irish Anaerobic Digestion sector.