Programme of Work 2013-2015

1. Objectives

The general objectives of Task 37 are:

The main objective of the Task 37 work programme is to address the challenges related to the economic and environmental sustainability of biogas production and utilisation. While there are many biogas plants in OECD countries, operation in the vast majority of cases can only be sustained with the help of subsidies to be able to compete with the fossil energy industrial sector. There is a clear need to enhance many of the process steps in the biogas production chain in order to reduce both investment and operating costs. Task 37 started the process optimisation work in the 2010-2012 work programme and will intensify this focus in 2013-2015.

Until recently the environmental performance of biogas production and utilisation was not assessed in a detailed manner and studies have started to highlight concerns about emissions of greenhouse gases at various stages of the biogas production chain. Task 37 started to address emissions in the 2010-2012 work programme and will focus special attention on environmental sustainability of biogas production and utilisation and establish best practices for emissions reduction.

In combination, process optimisation studies in Task 37 will attempt to significantly improve both economic and environmental performance of the biogas value chain where the end product is heat or electricity or biomethane for pipeline injection and use as a vehicle fuel and will include utilisation of the digestate.

2. Rationale

Based on many favourable reports over a number of years AD is a favoured treatment processes 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 green municipal waste and 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. However, AD is also a useful process for dedicated energy production and the production of renewable fuel in the form of biomethane from both purpose-grown crops as well as residues. 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.

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 2010-2012 triennium there were more than 8000 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 waste water treatment sites. However, while there is substantial further potential for expansion of the AD sector, based on availability of potential feedstocks, challenges to maximise the potential benefits in terms of energy yield and to reduce both investment and operating costs remain. 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.

3. Work programme

The work programme has been developed on the basis of three actions:

1. Information collated on the specific interests and on-going programmes in the IEA Bioenergy Member Countries through Task Members.
2. The status of trends in substrate availability, gas utilisation and biofertiliser utilisation.
3. Discussion and adoption of the Work Programme with the Task 37 members after their feedback from the national ExCo members.

A. Feedstocks and the AD Process

Demonstration of new developments and lessons learned (Success Stories).
The best method to improve deployment of the AD technology is to convince decision makers with the description of outstanding projects.

AD Process optimisation.
a) Evaluation of existing techniques for process control depending on operating strategy. Report to continue on from 2012 process monitoring report that was limited to the techniques currently used and those emerging and that should permit closer control of AD processes in the future.

b) Study of the kinetics of the AD process, specifically focussing on bacteria selection, process accelerators, inhibition and trace elements, all as a function of feedstock used in wet and dry processes, for the increase of methane yield and rate of production that will allow reduced reactor volumes and reduced costs. (If appropriate, parts a) and b) might be combined).

AD of source segregated biodegradable waste and biodegradable fractions of residual MSW.
This work will be carried out in collaboration with Task 36. It will include an evaluation of energy recovery and digestate aspects of the AD of the biodegradable fraction of municipal solid waste (biowaste) by Task 37 and LCA and the end-of-waste concept on digestate utilisation by Task 36. AD of food waste is rapidly expanding in many countries. An assessment will be made by the two Tasks of the drivers and levels of success that are being achieved so that best practices can be identified. In addition, the impact of source separation and the removal of the biological component on the composition and properties of the residual MSW need to be assessed by Task 36 in order that options for waste treatment system optimisation can be identified.

AD of sewage sludge/waste water treatment 
Sewage sludge is not treated in detail in the feedstock pre-treatment technical brochure and the waste classification of sewage sludge in most countries makes digestate problematic from the utilisation point of view. The challenge is to work effectively with low methane potential feedstock with account taken of co-digestion.

Biogas from Algae
With increased attention paid to fuels for the future, algae has come into focus as a feedstock for AD. AD of algae has received little attention and has not been considered in detail by IEA Bioenergy. A dedicated algae AD report will be published.

B. AD Products Utilisation

Up-grading 
Focus on small-scale systems and new developments in large scale technologies that have emerged or proven themselves in commercial operation since publication of the last up-grading brochure in 2009. There will be a special focus on economics of up-grading on both small and large scale. Workshops and meetings with operators, industry and decision makers will be organized alongside the Task meetings

Biomethane as a transport fuel 
Report on biomethane uses in all forms of transportation, from small to large engines, road, rail and water. To include engine performance, emissions (also compared to other fuels, including H2), filling stations and safety aspects. Where possible the work on heavy duty engines will be linked to IEA-AMF.

Digestate up-grading techniques 
Targeted at nutrient recovery, for example for regions with intense animal rearing; focus on nutrient capture, pelletisation of solid matter for export and residual water quality. To include descriptions of technologies, process economics and energy balance. This is a key component of the biogas value chain that has the potential to contribute significant benefits to overall sustainability.

C. Sustainability

Life Cycle Studies
LCA is becoming increasingly important as an assessment tool for energy technologies and in the future LCA results will have increased impact on decision makers. Task 37 will establish guidelines for LCA studies of the biogas value chain in order to provide a sound starting point for LCA and improve interpretation for policy makers. The possibility to standardise or benchmark a number of biogas pathways will be considered in collaboration with Task 38 and verified input data, for all major substrates (crops, animal manures, residues, sewage sludge etc.) will be provided as far as possible from existing databases.

Emissions management along the AD value chain
Description and assessment of measurement techniques used along the whole process chain, best operating practices, ranges of possible emissions depending on technology and how used, emissions inventory and emissions reduction techniques and strategies.

D. Horizontal Topics

Success Stories 
To be defined from the above Topics and will focus on projects that have proved successful in commercial operation and that can be used "visible proof" for visits by prospective new project planners and users.

Case Studies
Will be carried by Task 37 in order to complement other work carried out by the Task.

Support to Standards 
Technical input to national and international standards groups dealing with biogas and biomethane.

Workshops and Seminars 
Workshops and meetings with operators, industry and local/national decision makers will be organised alongside the Task meetings. Past Workshops organised by the Task (e.g. Copenhagen 2010, Den Bosch 2010, Istanbul 2011, Cork 2011 and Moss, 2012) proved very effective in fruitful discussions between technical experts, industry and policy makers.