Programme of Work 2016-2018

1. Objectives

The main objectives in the programme of work of Task 37 are:

To carry out expert technical work on sustainable digestion of substrates, associated reactor configurations and utilisation of produced biogas

- Biogas production from wastes, residues and by-products:
Assessment of optimised processes for mono-digestion of food waste. This includes analysis of operating systems in a number of countries using a range of different technologies. Assess long-term performance and define optimum digestion systems. Assess novel residue streams including from beverage industry, liquid biofuel production systems, biorefineries, paper industry and fish processing.

- Biogas outside Europe and biogas without subsidies:
Examine international applications of biogas facilities in regions such as Australia, Asia and Latin America. Assess the potential for low cost technologies and the potential for economically feasible subsidy-free digestion systems.

- Reactor configurations and operating parameters:
Assess high solids digestion systems, high rate
digestion systems, multi-phase systems and psychrophilic digestion.

- Biogas in grids:
Describe biogas upgrading systems, gas grid injection processes, and methods of greening of the gas grid. Highlight use of biomethane in energy/fuel supply of the future.

- Smart Grid applications:
Assess the provision of electricity at times of peak demand with production of biomethane (aligned with biological power to gas systems) for use as a transport fuel or source of renewable heat at times of low demand for electricity.

To provide expert technical support to assess the externalities of biogas systems:

- Socio-economic aspects of biogas utilisation:
Assess the real cost of biogas systems, including the benefits such as amelioration of impacts of agriculture and disadvantages such as methane leakage. Assess the environmental impact of biogas systems. Assess the role of alternative feedstocks with consideration of competition with other uses of biomass.

To provide guidance and advice on best practice to policy makers:

- Guide for recommended laboratory assessment.
Outline methods, which result in standardised repeatable results for laboratory assessment. Include a database of results from Biomethane Potential Assays (BMPs) carried out using good laboratory techniques.

- Best practice for use of digestate as biofertiliser and biomethane as substitute for natural gas:
Provide data on quality assurance of digestate and examine gas quality issues.

- Health and safety: Highlight all health and safety aspects of biogas systems.

To provide technical support to policy makers and to the public through:

- Providing a verified source of information on biogas production and utilisation to decision makers from both industry and governments.
- Assisting both member and non-member countries in adopting appropriate energy crop, agricultural residue and waste management practices to improve environmental performance, reduce emissions, provide an additional source of renewable energy and increase the number of jobs, particularly in rural areas.

- Providing verified data for determining greenhouse gas emissions used in sustainability assessment schemes.

- Providing guidance to standards organisations in the development of appropriate standards supporting commercial exploitation of biogas/biomethane in the energy and fuels markets.

- Stimulating interaction between RD&D programmes, industry and decision makers.

- Informing the general public via the Task website.

2. Rationale

The work of the Task will address technological aspects of anaerobic digestion (AD). Based on the technical knowledge and expertise of its members, the Task will provide support to policy makers, in the Member Countries during the implementation period, on expansion of renewable energy in an environmentally sustainable and cost effective manner.

Based on many favourable reports over a number of years AD is a favoured treatment process for organic residues and wastes, particularly for feedstocks with high water content. AD has been adopted by a range of sectors to tackle ground water pollution in agriculture, treatment of municipal sewage and treatment of the organic fraction of municipal solid waste. AD is used in a range of industrial processes to recover energy from residues while substantially reducing the overall impact of a primary process on the environment. AD is also a useful process for dedicated energy production from both purpose-grown crops as well as residues. Biogas when upgraded may be used for renewable heat and/or renewable gaseous transport biofuel in the form of biomethane. Indeed, AD may be a route in the future to third generation biofuel through digestion of micro-algae and macroalgae (seaweed). Biomethane injection to the natural gas grid allows distribution from the biogas production site to the consumer. Power to gas systems (where excess electricity is converted to gas) coupled with AD systems may eliminate the COcontent of the biogas, whilst facilitating greening of the gas grid. Both Power to Gas systems and demand driven biogas concepts facilitate higher portions of intermittent renewable electricity in smart energy grids. The AD process has the added benefit of preserving nutrients found in the feedstock and allowing these nutrients to be recycled back to the soil, thereby reducing the amount of fossil-derived fertilisers needed for subsequent crop production. AD provides additional income and jobs in distributed installations, often in rural communities. It may provide a cost efficient route to sanitation in underdeveloped areas, whilst simultaneously providing fuel for cooking and electricity generation.

The AD treatment of agricultural residues helps to reduce greenhouse gas emissions of both methane (CH4) and nitrous oxide (N2O). It also promotes better hygiene in relation to safe treatment of animal by-products and provides better recycling of nutrients back to the soil. Life cycle studies show that biogas from residues saves considerably more greenhouse gas emissions than first generation liquid biofuels for transport, bioethanol and biodiesel. A greater energy yield per hectare is achievable with biomethane than with first generation liquid biofuels. The treatment of green wastes or biowastes, likewise, enables the production of renewable energy, saving CO2 emissions, while providing an effective alternative to landfilling of waste that leads to higher CH4 emissions. However, more recent studies have highlighted potential high methane emissions from various steps in the biogas value chain. The sources of these emissions need to be identified, quantified and eventually reduced to an acceptable level.

By the end of the 2013-2015 triennium there would be more than 11,000 biogas installations in the Member Countries of Task 37. IEA has played a significant role in the definition and promotion of best available biogas technologies that are in use on farms, in organic waste treatment facilities and on wastewater treatment sites. However, while there is substantial further potential for expansion of the AD sector, based on availability of potential feedstocks, challenges remain to maximise the potential benefits in terms of energy yield and to reduce both investment and operating costs. There is a well-understood need to reduce the reliance of biogas plants on subsidies such as investment grants, feed-in tariffs and green certificates.

AD has an important role to play in the future of sustainable agriculture, rural development, waste management and renewable energy/biofuel production. IEA Bioenergy has an important role to play in the further sustainable development of AD technologies and provision of support to the relevant policy makers.