Anaerobic digestion plants that turn waste and purpose grown crops into energy have the potential to power more than 2.5 million UK homes by 2020, a new report by CentreForum suggests. Yet the think tank warns that this vision will only be realised if certain barriers to sector growth and development are removed.

The report ‘Hit the gas’ sets out a number of advantages to expanding the anaerobic digestion sector. It praises anaerobic digestion for generating a multi purpose biogas that is easy to transport and store, and for diverting food waste from landfill.

Anaerobic digestion currently produces around 1.3 TWh of energy in the UK – enough to power 300,000 homes. CentreForum believes that the sector can expand by more than 800 per cent (11 TWh or 2.5 million homes) over the next eight years if the recommendations of its report are followed.

Ed Davey, Secretary of State for Energy and Climate Change, says: “The government is committed to promoting an increase in energy from waste schemes through anaerobic digestion. CentreForum’s report offers some interesting ideas for how this increase can be achieved.”

Report co-author Quentin Maxwell-Jackson comments: “”Anaerobic digestion technology has so many clear advantages over other waste treatment and energy generation options that it is very surprising it has not taken off in a big way yet in theUK. But that is because trying to get an anaerobic digestion scheme up and running at the moment is like trying to win a cycle race with the brakes on.”

The report’s other author Thomas Brooks adds: “There are some simple things government can do to release the brakes on anaerobic digestion. For instance, simply banning organic waste to landfill inEngland, as they are already planning to do in Scotland, would give anaerobic digestion a huge boost.”

Lord Redesdale, Liberal Democrat peer and chairman of the Anaerobic Digestion and Biogas Association (ADBA), says: “CentreForum have shown that anaerobic digestion already represents a significant part of the UK’s renewable energy mix – generating four times more electricity than solar PV – and are pushing for government to support an 800 per cent increase in that generating capacity by 2020.”

The Anaerobic Digestion and Biogas Association (ADBA) in the UK has launched its new farmers’ consultancy service. The service, which is free of charge, will help farmers and landowners decide whether AD is a viable option for them to consider.

Farm-based anaerobic digestion (AD) presents an opportunity for UK farmers, growers and land managers to improve yields, create a new income stream, and reduce their greenhouse gas emissions by generating their own renewable energy and biofertilisers.

ADBA’s chief executive Charlotte Morton comments: “Today’s farmers are facing a tough economic climate made even more challenging by soaring energy, fertiliser and transport costs. AD not only helps farmers to reduce their greenhouse gas emissions by reducing dependence on commercial fertilisers and traditional transport fuels and energy consumption, but also helps keep farmers farming.”

She adds: “ADBA has launched this free service to give farmers, growers and land managers a better understanding of what is involved, giving them the confident to invest the time and money needed to develop a project proposal for funding.

Grocery retailer Sainsbury’s is using experimental technology to help reduce the UK’s dependence on fossil fuels. Many people are unaware of the strain the National Grid comes under at peak times, as coal-fired power stations across the country have to be ‘switched on’ to meet the increased demand on the UK’s electricity supply.

Power station malfunction and the unpredictability of wind power can also cause changes in supply to the grid, but such changes could become more manageable thanks to the innovative ‘Smart Grid’ system at the new Sainsbury’s store at Hythe in Kent.

The system monitors the grid and activates the store’s biofuel generator when there is an increased demand for electricity. As a result, reserve power stations will not have to be used as much and the UK’s carbon footprint will be reduced.

The generator is the first of its kind and will be powered by waste oil and fat from Sainsbury’s stores to act as an auxiliary power source. Additional technology in the store will reduce strain on the grid further by deactivating or reducing the store’s heating, ventilation and lighting systems at peak times.

The introduction of the Smart Grid system is part of Sainsbury’s environmental stores programme, through which the company invests in environmental technology to drive energy and carbon efficiency in an effort to lessen the impact of climate change. Technology trialled in environmental stores is often rolled out to future store developments as standard.

Sainsbury’s has been at the forefront of environmental store development for many years. It was the first retailer to use anaerobic digestion at scale to dispose of food waste, and opened the first store to be heated and cooled using geo thermal energy last September.

The creation of the Smart Grid store is the first major output of Sainsbury’s partnership with Imperial College London’s Faculty of Engineering and Grantham Institute for Climate Change. The partnership, which launched last year, was created to develop technologies and solutions that will help Sainsbury’s lower its carbon footprint to help it meet with future climate change legislation, and continue to be the UK’s greenest grocer.

Northern Ireland Energy Minister Arlene Foster has welcomed European Commission State Aid approval for proposals to increase support for small-scale renewable electricity. The European Commission has ruled that electricity generated from anaerobic digestion can now receive up to double the support currently offered under the Northern Ireland Renewables Obligation (NIRO).

Subject to approval by the Northern Ireland Assembly, the change in legislation will increase the ROC levels for electricity generated from anaerobic digestion from the current two ROCs per megawatt hour for all sizes to four ROCs per megawatt hour for generating stations up to 500kW capacity and three ROCs per megawatt hour for stations between 501kW and 5MW.

An anaerobic digestion installation.

Welcoming the Commission’s approval, the Minister says: “This is further good news for Northern Ireland’s renewable energy sector. The enhanced support for anaerobic digestion, will help stimulate this important renewables technology, whilst bringing wider benefits, particularly to the farming community.”

In addition to the enhanced ROC levels for anaerobic digestion, State Aid approval was also received for additional generating capacity installed by those renewables generators accredited under the NIRO before 1st April 2010. Anyone who did not receive the enhanced ROC levels for new generators accredited from 1st April 2010, will now receive the higher levels for any further capacity they add.

These and other proposals will be introduced in the Renewables Obligation (Amendment) Order 2011 which will be subject to approval by the Northern Ireland Assembly in March for introduction on 1st April 2011.

British households are now cooking and heating their homes for the first time with renewable gas produced from sewage. Biomethane gas from Didcot sewage works in Oxfordshire will produce enough renewable gas to supply up to 200 homes.

The landmark project at Didcot – a joint venture between Thames Water, British Gas and Scotia Gas Networks – marks an important milestone in the UK’s efforts to decarbonise the gas grid and move towards a low-carbon economy. It is expected that this will be the first of many similar projects.

Biomethane from all sources will make a contribution to decarbonising the gas grid by delivering renewable heat to households through the existing gas network and central heating boilers. According to a study by National Grid, it could account for at least 15% of the domestic gas market by 2020.

Sewage arrives at the Didcot works from some of Thames Water’s 13.8 million customers to be treated and recycled back to the environment. Sludge, the solid part of sewage, is then treated further in warmed-up vats in a process called anaerobic digestion, where bacteria break down biodegradable material, yielding biogas.

Impurities are removed from the biomethane before it is fed into the gas grid. The whole process – from flushing a toilet to gas being piped to people’s homes – takes around 20 days. The project took six months to complete and cost £2.5 million.

“We already produce £15 million a year of electricity by burning biogas from the 2.8 billion litres a day of sewage produced by our 13.8 million customers. Feeding this renewable gas directly into the gas grid is the logical next step in our ‘energy from waste’ business,” points out Martin Baggs, chief executive of Thames Water. “What we have jointly achieved at Didcot is a sign of what is to come, which can be replicated across our network and indeed the whole country. Every sewage works in Britain is a potential source of local renewable gas waiting to be put to use.”

The extent of the potential for anaerobic digestion has yet to be realised in Ireland, according to an expert consultant from WYG, the international professional services group. Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen, used for industrial or domestic purposes to manage waste and/or to release energy. It is widely used as part of the process to treat wastewater.

WYG recently strengthened its growing specialism of anaerobic digestion (AD) with the appointment of expert Dr Kevin Monson who is based in Dublin.

With over ten years experience in the anaerobic digestion field, Kevin Monson believes that the full potential for AD has not yet been realised in Ireland. He says: “Anaerobic digestion, having widely been used as a wastewater treatment option, has now evolved into a viable organic wastes treatment technology that can be utilised as a means to divert many organic wastes from landfill. Anaerobic digestion is also increasingly seen as a renewable energy technology, and in many cases the production of renewable energy (rather than the treatment of wastes) may be the primary driver.”

He adds: “As well as the municipal wastes sector, the anaerobic digestion of agricultural wastes (and energy crops) has real potential in rural Ireland. We can educate and advise farmers and land-owners of the options available to them to optimise their agricultural waste management, and support them to take anaerobic digestion projects from conceptual idea to project realisation, resulting in an increase in the number of operational and profitable anaerobic digestion plants.”

A new static gas analyser for anaerobic digestion (AD) biogas, and landfill gas monitoring has been designed to suits tight-budgets. The new GA3000 uses Geotech’s robust, field-proven technology to bring low-cost to automated fixed-position monitoring of methane-rich biogas. Easily operator installed, user field-calibrated and zeroed, the compact, self-contained, single-cabinet GA3000 has gas conditioning as standard. It continuously analyses CH4, CO2, O2 and optionally, H2S at 0-5000ppm. They are measured, at user-set timings, and supply data via three or four, 4-20mA local outputs. Users also set alarm levels and can see screen-displayed readings on a large, clear, backlit display.

Low cost, single-point fixed biogas monitoring, the Geotech GA3000 gives top-quality and economy.

The strong interest in the GA3000 is its application for AD, wastewater sludge treatment and landfill gas extraction. The GA3000 is available from September 2010.

AD is increasingly being used in waste processing and biogas production to recycle food and farm waste, avoid landfill and generate biogas and energy from waste. These AD installations, large and small, need continuous gas analysis to optimise AD, maximise output and ensure safety and compliance with environmental guidelines and legislation.

This new robust, reliable and cost-effective system provides continuous and accurate sampling of methane, carbon dioxide and oxygen from a single sample point. Hydrogen sulphide sampling is a GA3000 option. User field calibration of the analyser and exchange of the optional hydrogen sulphide (H2S) sensor reduce operational costs.

With no training required and engineered for low ownership cost, this ISO 17025 calibration accredited unit is designed for quick and easy self-installation in any country, worldwide. User relocation of the GA3000 is just as easy. With gas conditioning included as standard, to ensure top quality gas analysis, the user-replaceable H2S sensor and analyser ‘Hot Swap’ capability offers zero downtime.

The GA3000 adds to Geotech’s static gas analysis range. For more information visit www.geotech.co.uk.