Last week, the Government unveiled its plan detailing how they will kickstart a new anaerobic digestion (AD) industry to produce renewable gas and reduce emissions in the Republic of Ireland.

The document outlines 25 measures, actions and timelines that will be completed by a new Biomethane Implementation Group. This group includes key departments, Teagasc, the SEAI, the EPA and the Ireland Strategic Investment Fund. Here are the key takeaways from the strategy:

1. The model

The AD model which will be developed in Ireland is unique. The Government wants to see large-scale, centralised AD plants supplied with grass silage and slurry from farmers. Nowhere in the world has this been done at such a scale, or explicitly designed this way by a government.

The optimal size of an AD plant, as outlined in the strategy, will produce 40 gigawatt hours (GWh) of gas, which is enough to power 6,400 homes. A plant of this size will require around 2,000ac of grass silage and up to 30,000t of slurry per year. Waste and other organic sources will likely also be used in some plants. A plant of this size will cost around €15m to build.

The first wave of projects will be built by commercial developers, but there are also a handful of farmer-led projects, which have secured and are going through planning.

2. Timelines

The Government wants to see one terawatt hour (TWh) of biomethane produced by the end of 2025. This will require around 25 40GWh plants to be built. However, only about 18 new projects may be eligible for funding, those which have planning secured or are going through An Bord Pleanála.

One TWh equates to 1.7% of Ireland’s natural gas demand today. The Government remains committed to its 2030 5.7TWh biomethane target, the equivalent 10% of today’s natural gas use. The volume of biomethane injected into the grid today is equivalent to just 0.001% of Ireland’s current gas demand, so the challenge is massive.

3. Grid connection

The vast majority of new plants will connect directly to the national gas grid, injecting biomethane into a pipeline. Under the Gas Networks Ireland’s (GNI) Connections Policy for biomethane, AD plants will be required to pay 30% of the connection cost, with the remaining 70% covered by GNI subject to economic tests.

However, in practice, developers will have to have a financial bond in place covering the remaining 70% as security for a period of time. This essentially means developers will have to borrow 100% of the connection cost, running into the millions.

Moreover, GNI currently charges three-to-four times more per kilometre of pipeline for a new connection compared to the EU average of around €250,000/km. This is making it economically unfeasible for some projects to connect to the grid. In recognition of this issue, a review of their connections policy is planned by Q3 2024, which will examine the costs, the necessity for financial bonds, timelines and whether a developer can lay their own pipe.

4. Support

The Government will introduce capital grants in an attempt to reduce the cost of building AD plants and ultimately the price developers need for biomethane. Biomethane is around three-to-four times more expensive than wholesale natural gas.

They will then introduce an obligation, forcing suppliers of fuel to the heat sector to use renewables or face fines, stimulating the market for biomethane. The first competitive grant funding call is now open, where up to 18 projects will compete for a slice of the €40m grant.

No details about the terms and conditions of the scheme have been announced yet, such as if the plant must be connected to the grid, use agricultural or waste feedstock, or if the biomethane and its emissions reduction credits must be used within the Republic of Ireland, or if they can be exported to the UK or EU.

The Department of Agriculture will fund these projects, while the Department of Environment will fund another 1.4TWh of projects from 2026 onwards in a second round of funding.

5. Market for biomethane

It is intended that the biomethane will be used by companies in the Republic of Ireland to decarbonise their heat use, transport or electricity use, reducing national emissions. Anywhere that natural gas is currently used can be replaced with biomethane. This will be done through private gas purchase agreements.

An export market for biomethane also exists, and once in the grid or transported by trailer, it can be exported out of Ireland to the EU, GB or Northern Ireland.

The majority of the customers of biomethane will be connected to the grid, but the strategy commits to developing a process to certify the end use of non-grid-injected gas by Q4 2024. GNI will also procure biomethane from Q3 2024 to decarbonise its operations.

6. Small-scale plants

Biomethane production requires economies of scale to be viable, hence the reason why we are seeing many large plants going through the planning process. It will be difficult for a farmer to secure planning, finance, develop and run a plant of this scale. In recognition of this, the strategy commits to assessing the potential for an appropriate smaller-scale finance scheme for 10GWh AD plants (this is the same size as the average farm-sized plant in Northern Ireland) by Q4 2024. The economics of small-scale biomethane production today remain extremely challenging for new AD plants.

7. Sustainability

The AD sector will have to adhere to strict sustainability criteria outlined in a new Biomethane Sustainability Charter. Developers will have to sign up to the charter in order to access funding, as will feedstock suppliers and users of digestate. Biomethane must reduce emissions by a minimum of 70% compared to natural gas under the Renewable Energy Directive and this will increase to 80% by 2026.

Feedstock also cannot be produced on land that was formerly peatland, has a high biodiversity value or has a high carbon stock. The charter will also cover issues relating to land use, water quality, biodiversity, fertiliser use and carbon sequestration. The charter will be delivered by Q3 2024.

8. Digestate and nitrates

Digestate will be used by farmers as an organic fertiliser.

The strategy also commits to exploring supports to further process digestate into biobased fertiliser and products by Q4 2024.

The document states that AD with digestate processing will allow for centralised management of manure in areas of surplus nutrients and creates an opportunity to support compliance with the Nitrates Directive limits.

9. Planning permission

The strategy cannot change the planning process or fast-track applications. Instead, it commits to developing guidelines to support local authorities when assessing AD and biorefinery planning applications by Q4, 2024.

10. Resourcing

The strategy also commits to reviewing the resourcing requirements of key Government agencies to support the development of the biomethane industry and speed up EPA licensing, animal by-product licensing and the planning process.

An AD plant which proposes to use waste will need either an EPA licence, which can take up to 12 months to secure, or a local authority licence.

Agricultural-based AD plants which only use slurry do not need a waste licence or permit.

However, they will need to pasteurise their digestate, which adds millions in capital and running costs to the project.

In contrast, agricultural-based plants in countries with well-established biomethane industries, like Denmark—a model often cited for Ireland—do not require pasteurisation.

Biomethane conference

The 2024 Biomethane Conference is set to take place next week, 12 June in Croke Park, Dublin. The Government’s plan to develop 150 to 200 anaerobic digestion plants and a farmer centric bio-economy, will be the focus of the conference. The event is organised by the Renewable Gas Forum Ireland and speakers include Ministers Ryan and McConalogue, policy makers, developers, farmers and industry. To register for the conference, go to

The author Stephen Robb is currently involved in a family/community proposal for an anaerobic digestion facility in Co Donegal.