Ireland’s future anaerobic digestion (AD) developers intend to produce enough biomethane to supply 26% of Ireland’s gas demands, which is more than two and a half times the current 2030 target.
This is according to a significant new report by Gas Networks Ireland (GNI), which was published this week.
In 2022, Ireland’s gas network transported enough natural gas to supply 57.1 TWh (terrawatt hours) of energy to Irish industries and households, almost twice the volume of energy transported on the electricity grid at 32TWh.
However, decarbonising natural gas use remains a significant challenge. Biomethane, a renewable gas, is structurally identical to natural gas and can be injected into the existing network to be used interchangeably with natural gas.
It is produced by AD plants and, when the correct feedstocks are used, can be carbon neutral.
However, as Ireland’s biomethane sector is in its infancy, many aspects about how this sector will develop remain unclear. To provide an insight into this, GNI issued a request for information (RFI) to prospective biomethane producers in October 2022.
The RFI aimed to identify new and feasible biomethane projects and to assess the future infrastructure requirements for integrating biomethane into the gas network.
The RFI provides a snapshot of prospective biomethane production in Ireland and helps to better understand the status of Ireland’s emerging biomethane market.
A total of 176 prospective biomethane producers responded to GNI’s RFI, with a combined biomethane production potential for 14.8 TWh per annum, a quantity of energy greater than that procured from Ireland’s first offshore wind auction, ORESS 1, which took place earlier this year.
Currently, Ireland’s 2030 Climate Action Plan biomethane target is to produce 5.7TWh (10% of current gas supply), so there is enough interest from prospective producers to more than double this target.
It’s important to note that the figure from the RFI is from prospective biomethane producers, many of which are years away from progressing with a project, if at all.
Average size of plant
In terms of AD plant size, out of the 176 responses received, almost 60% or 105 responses, were sized between 40 gigawatt-hours (GWh) to 55 GWh in annual biomethane production capacity.
For context, a 40 GWh agricultural plant would require around 2,000 acres of grass silage and approximately 25,000-30,000 tonnes of slurry. A plant of this size would cost around €15 million to construct.
GNI states that, based on the responses received and considering trends across Europe, the likelihood is for a smaller number of larger plants to be developed as the biomethane market evolves in Ireland. Therefore, to meet the 2030 target, approximately 150 40 GWh plants would need to be built.
The EU is relied upon throughout this report as a benchmark, given that it is the world’s largest producer of biogas and biomethane. The RFI’s findings compares with an average biomethane plant size of 35GWh at the EU level.
The RFI responses indicate that approximately 80% of the required AD feedstock is expected to come from agricultural sources.
Specifically, about 38% of the feedstock will be obtained from slurry, 28% from grass silage and mixed-species swards, 14% from various other crops, 11% from commercially available biodegradable materials, and 8% from by-products.
County by county
Leitrim was the only county in the Republic of Ireland where no RFI responses were received. Respondents from Monaghan, Kildare, and Limerick had the highest level of biomethane production intention, respectively. Cork and Monaghan also rated highly in terms of production intention. Limerick, Tipperary and Cork received the highest number of responses.
Other counties such as Longford, Carlow, and Wicklow, however, had a comparatively low response rate, with nine counties having responses totalling less than 100 GWh.
Responses from Northern Ireland relate to several projects near GNI’s transmission network and amount to 166 GWh in capacity.
If the intended biomethane production figures outlined in the RFI was derived from agricultural feedstock, this would result in 3.94 Mt CO2 equivalent of emissions savings annually. To put this in perspective, agriculture’s emissions for 2022 amounted to 23.34 Mt CO2 equivalent.
An analysis was carried out on each of the 176 respondents, revealing that 50% of the projects are within 5.6 km from the gas network, and 64% of projects are within 10 km of the existing networks.
Of these, 72 projects aimed to connect to the lower pressure distribution network, while six projects sought to connect to the high-pressure transmission network.
Direct connections are vital, as in other countries with established biomethane industries, connecting an AD plant directly to the gas network is the most convenient route to market.
Under the Connections Policy, AD developers must pay a minimum of 30% of the connection costs upfront, with GNI recouping the remainder over time.
Of the projects, 98 are located too far away from the grid to connect directly, so they will have to transport their gas by road in tankers to a central injection facility or directly to an end customer.
Three to five new central grid injection points would be needed to accommodate these plants. Currently, there is just one private facility operational, and another is planned in Cork.
Progress to date
Almost 70 new biomethane plants were delivered in Europe in 2022, bringing the total number of operational plants to 1,137, with a maximum installed capacity of more than 196 TWh of annual production.
Two existing producers in the Republic of Ireland produced just 41 GWh of biomethane in 2022 and are expected to produce 62 GWh in 2023. In order to meet our 2030 target (5,700 GWh), Ireland would need to increase biomethane production by over 9,000% compared to 2023 levels, requiring the construction of 150 new plants.
The European Biogas Association estimates that a total of €1.4 billion of investment would be needed to develop Ireland’s 2030 targets, both in terms of new AD plants and gas infrastructure.
However, as Ireland currently doesn’t have a support scheme in place, no new AD plants are currently being constructed.