Developing an AD Project

This section provides outline steps for developing an AD plant, from the initial project idea to the feasibility study, planning, grid connection and animal by-products regulation and financing.



The most important factor for the implementation of a biogas project is the existence and availability of the feedstock supply. Furthermore, the possibility of selling or using the end products (biogas/biomethane, electricity heat, digestate) has to be ensured.

Some important and fundamental questions should be considered when building a biogas plant.

  • What quantity and quality of substrate materials do you have per day/per year? Are the materials and the amount constantly available for the next few years? How expensive are the materials? Is the price expected to remain stable?
  • What kind of planning permission, animal by-product permission, waste permits do you need? What are the regulations?
  • Do you have any co-substrates, energy crops, animal by-products, organic waste?
  • Could you use agricultural residual substances or organic waste e.g. canteen waste? How much money will you get for the waste?
  • Does the co-substrate have to be disinfected? Do you have enough space/capacity for the substrates and digested material (silo for chopped energy crops, lagoon)?
  • Where can the digested material be spread?
  • How fast will you get grid connection? How much will it cost?
  • Do you have enough time to operate a biogas plant economically (for 500kW plants up to 5 hours a day)?
  • What amount of electricity and heat does the farm / household need currently and in the future? Is it economically viable for you to use the heat and electricity on site?
  • What is the price for electricity and heat in the future?

The economics of a biogas plant is generally difficult to determine. In practice a detailed list of all costs should be calculated specifically for your plant.

Please download more specific information on the economics of a biogas plant here:Economics of a Biogas Plant.pdf (size 296.2 KB)

First steps in planning an Anaerobic Digestion (AD) facility

Tom O'Neill, Forward Planning Section, Limerick County Council

The first step when planning an AD facility is to request a pre-planning meeting with the planning section of your local County Council. It is advisable to request that representatives from the Planning and Environment Sections are present. Note the following points for the meeting:

  • Bring a simplified schematic drawing with you explaining the AD process and the structures involved. This document can be generic in nature. For many this meeting could be their first encounter with the AD process therefore the schematic needs to explain the process clearly and also to indicate the structures used, e.g. storage tanks, the digester, Combined Heat and Power Unit (CHP), pumps, gas covers and control buildings. It would also be important to indicate if electricity is to be exported to the grid and the possible route such a connection would take. If it makes use of previously existing connections then this should be emphasised. Other processes, such as the pasteurisation or disinfection of incoming feedstock, should also be highlighted on the drawing.

Note: drawings, structures of plant/plant components and process description should be supplied by your developer or supplier. For general AD basic information and the digestion process itself see also the Biogas Getting Started handbook.

  • Questions are bound to arise as to the destination and end uses of the digestate and liquor. Since these substances have a nutrient content this will be of particular interest to representatives from the Environmental Department and in particular to the agriculturally qualified personnel. If the digestate is to be used on a farm this will require alterations to any nutrient management plans (NMP's) that may be in place.

Note: for the utilisation of digestate see also section 6 of the Biogas Getting Started handbook.

  • The possible use of nutrient rich material from a river catchment area, if applicable, must be addressed. It is likely that nutrient rich material might have to be exported from the catchment area if soils are over-enriched with nutrients. It is important for the intending developer to factor this into his business plan.
  • The origins and nature of the feedstock used should be indicated. This will have implications for traffic movements; it is worth making the point though that an existing farm enterprise would already have traffic to and from it with feed and livestock lorries, movements of agricultural machinery and milk lorries for example. The additional traffic should be viewed in this context. The scenic effects of the AD development should also be viewed in the context of existing farm buildings. The final locations and separation and distances of AD structures would of course be dictated by the Department of Agriculture regulations.

Go to Animal By-Product Regulation for more information.

  • The Environmental Department will be able to clarify whether or not a waste permit will be required. An EIS (Environmental Impact statement) will be required where the feedstock might be deemed as waste. The annual intake would have to be 25,000 tonnes or over to trigger the EIS threshold. In the situations encountered by Limerick County Council, no EIS was requested for the agriculturally-based AD projects which went through the planning system.
  • Issues such as odours should also be discussed. It is likely that any odours would come from the feedstock arriving rather than from the process itself. In an agricultural context it is worth pointing out that subjecting animal wastes and slurry to the process would lead to a reduction in the odours that might arise from the handling and use of nutrient rich material. Such easily handled nutrients could also be incorporated into Nutrient Management Plans replacing energy intensive chemical fertiliser.

Note: For information on odour see also Section 6 in the Biogas Getting Started handbook.

  • Safety issues on an Anaerobic Digestion facility could arise and safety measures such as venting gas and built-in safeties associated with different AD systems should also be explained.

Note: Safety issues and safety measures must be issued by your developer or supplier; in this context see also Section 9, "Safety on Biogas plants" in the Biogas GettingStarted handbook.

How to get grid connected

The following guide provides information on connections to the Irish electricity grid for renewable and combined heat and power (CHP) generators of various scales. It is intended to explain the process involved in obtaining a grid connection for a generator installation. Its main aim is to provide a ‘route-map’ for the process of getting a generation scheme connected to the network. The connection offer process involves agreements between the developer and the system operator. As such, the process is more likely to be successful if the parties can communicate effectively and understand each other’s concerns.

Each generation scheme has a unique set of technical and commercial circumstances, so it is not possible to provide specific guidelines and solutions that apply for the design of connection arrangements. The guide is intended to give the reader a general understanding of the issues which affect the connection of renewable generators. It addresses the connection of renewable and CHP generator installations of all sizes except micro generators. A separate guide is available with information on connecting micro generation to the grid, micro generation being defined as generators that produce less than 11 kW (3 phase) or 6kW (single Phase) of electrical power.

Download Connecting Renewable and CHP Electricity Generators to the Electricity Network

Download Connecting Micro-Generation to the Electricity Network

For getting a grid connection see also CER decision paper of the treatment of small, renewable and low carbon generator outside the Group Processing Approach (GPA). The purpose of the paper is to outline the Commission's decision following the comments received to the consultation document "Treatment of Small, Renewable and Low Carbon Generators outside the Group Processing Approach" (CER09/044) published on 27 March 2009. The Group Processing Approach is the process by which renewable generators receive a connection offer to either the transmission or distribution system; the current iteration is Gate 3. Therefore this decision document details how small, renewable and low carbon generators that fulfill public interest criteria would be processed outside the GPA. The public interest criteria and the classes of technologies that fulfil these criteria are also set out.

You will find more useful information under the following links:

Decision Paper Treatment of Small, Renewable and Low Carbon Generators outside the GPA

Connecting to the Network

Guide from the ESB how to connect a renewable generator Connect a Renewable / Embedded Generator

Animal by-products

According to ABP-Regulation (Animal By-Product Regulation), a biogas plant is one in which biological degradation of products of animal origin is undertaken under anaerobic conditions for the production and collection of biogas. ABP include the bodies of animals, parts of animals or products of animal origin that are not intended for human consumption. A large amount of catering waste and former foodstuffs also fall within the definition of ABP. In the ABP-Regulation animal by-products are divided into 3 categories:

Category 1 contains those materials with the highest risk for public health, animals, or the environment (hygienic risk, risk of BSE, etc.).

Category 3 comprises those animal by-products which would be fit for human consumption, but are (for commercial reasons) not intended for human consumption.

Category 2 includes all animal by-products which cannot be allocated to either Category 1 or Category 3 (e.g. manure or digestive tract content or animals not fit for human consumption).

For manure and catering waste the conditions for approval and for treatment, as well as other criteria for the end product other than for the remaining animal by-products, are defined. Biogas plants which process catering waste or manure can be approved by national rules (pending further EC-legislation).

The use or disposal of ABP is strictly controlled. This is to protect both public and animal health. If you are involved with ABP you must follow all appropriate rules and regulations.

The plant must be registered and approved by the Department of Agriculture, Fisheries and Food (DAFF). The digestate of this biogas plant can be considered as “untreated manure” and placed on the national market or applied to land or pasture land. Trade between EU Member States is allowed only with special permission. Hygienic parameters for manure products must be observed for its production and subsequent placing on the market.

The purpose of the document Conditions for approval and operation of biogas plants treating animal by-products in Ireland is to set out the approval and operating conditions required by DAFF for a plant involved in the transformation of animal by-products in Ireland.  The requirements apply to a plant involved in the transformation of any feedstock referred to in Section 2 unless otherwise specified.

These conditions do not apply to those plants involved in the transformation of animal by-products which are authorised as an alternative system in accordance with EU Regulation No.197 of 2006 as amended.


Financing an AD Project

Financing is one of the key elements of ensuring project viability. In general low interest long-term loans are used for financing biogas plant projects.

A single farmer, a consortium of farmers or a municipality are the most likely to implement successful biogas projects. The success of the project depends on some factors that can be controlled and influenced by strategic decisions concerning investment and operational costs. Choosing the best technology in which to invest and calculate operational costs is very difficult.

If tendering a biogas plant, it is important to outline the following costs:

  • Operational cost of CHP including all services and spare parts (amount/kWh)
  • Maintenance costs of biogas plant in total (% of investment/year)
  • Own electrical energy demand, including demand of CHP (kWh/year)
  • Average working hours/day of staff (maintenance and feeding the system)

The success of the project is also influenced by some factors that cannot be controlled such as:

  • Interest terms
  • Grid access and feed-in tariffs
  • World market prices for feedstock (e.g. energy crops)
  • Competition for feedstock from other sectors

Quite often, before a bank offers to finance the biogas plant project, the economical long term success of the project must be proven by a study/calculation of profitability. The calculation is normally done within the preliminary planning by an experienced planning / consulting company, but in many cases, especially in the case of single farm based biogas projects, this work can be done by the project developer, as the project developers / partners are forced to have a very close view to the different aspects of the project.

The revenue side of a project is difficult to influence. The feed-in tariffs are set by the government. In case of waste treatment plants, the gate fees are market prices. There are other possibilities on the income side like using/selling the produced heat and selling digestate as a fertilizer.

Further information

Download the presentation Financing a Bioenergy Project by Helen O'Sullivan, ACC Bank/Rabobank
Download Proceedings of the Teagasc Bioenergy Conference 2009 including the presentations referring financing Anaerobic Digestion projects: Financing a Bioenergy Project - Hans van den Boom, Rabobank

Checklist for developing an AD project

Each project is individual and needs a unique approach (site specific project). It starts with a pre-feasibility study and ends with a concrete overview of the technical and economical situation (see page on economics).  

By answering all of the following questions you get a more concrete overview of the whole project. 

Download Checklist for developing an AD plant project.

Useful Documents
  • Download Biogas Handbook presented by the University of Southern Denmark
  • Download Proceedings of the Teagasc Bioenergy Conference 2009. Included are presentations on:
    • Financing a bioenergy project - Hans van den Boom, Rabobank
    • Biomass and the planning system - Ciaran Lynch, Martin McCormack, Tipperary Institute of Technology
    • Making Anaerobic Digestion a commercial reality - David McDonnel, Limerick farmer

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