Bioenergy:the next generation09 February 2011

Biomass plants are more advanced and more prolific than many realise. Birmingham City University's head of bioenergy research Dr Lynsey Melville looks at what's out there – and the future

July 2010, a year after the former UK government published its Low Carbon Industrial Strategy, saw Britain, France and Germany announce a joint push to raise the 2020 emissions reduction target from 20 to 30%. At the time, Energy and Climate Secretary Chris Huhne commented: "This shows how seriously the three countries take the low-carbon agenda and how we want to work together to make it happen."

Meanwhile, DeFRA's (Department for Environment, Food and Rural Affairs) 2007 UK Biomass Strategy states that 'biomass has a central role to play in meeting EU-targets for renewable energy by 2020'. And that is happening, with the Department of Energy and Climate Change (DECC) recently revealing that the proportion of electricity generated by renewables reached 6.6% in 2009. Interestingly, it also showed that, although wind, solar and tidal sources are assumed to make up the lion's share of that power generation capacity, in fact biomass-generated energy – which overcomes the intermittency of its higher profile rivals – contributed fully 44% of 2009's total.

That is encouraging – except that the most recent European Biomass Association (AEBIOM)'s annual report shows good progress among Europe's 27 members, but lists UK among the laggards for biomass generation. Nevertheless, the Biomass Strategy indicated ambition, identifying biomass as a 'very versatile' as yet 'untapped resource' – and a fuel that could be used across the energy spectrum, for electricity, heat and transport.

And indeed DeFRA has supported significant expansion in biomass use – seeking, for example, to develop a competitive and sustainable market and supply chain, by promoting innovation and technological developments. It is worth remembering that, while wanting biomass to deliver high energy yields, DeFRA has also been active in encouraging wider ecosystem benefits, through best land-use and sustainable growth in biomass-based energy developments
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So what is out there? Harper Adams University College (HAUC) is Britain's leading centre for farming, agricultural and related studies, which is why the government and Advantage West Midlands (AWM) commissioned it to run the West Midlands' BioenergyWM programme. This is currently helping to develop a dedicated regional bioenergy supply chain by bringing together producers, processors, end-users, consultants, manufacturers and local authorities.

As a result, an infrastructure is now emerging, inspiring self-sufficient bioenergy programmes at organisations such as Severn Trent. One of its sewage treatment plants, for example, now processes 4,000 litres of sludge daily through anaerobic digestion, with resulting biogas fuelling a CHP (combined heat and power) generator – making the plant self-sufficient in electricity.

HAUC is also now installing its own 350KWe waste-to-energy plant, utilising its own farm and food waste to generate renewable power through its award-winning CHP system. This will see HAUC's extensive campus also becoming virtually self-sufficient in electricity.

And it doesn't stop there. Contact with overseas bodies, through managing BioenergyWM, has also provided the centre's sustainability team with insights into activities in countries more advanced with biomass fuelling for decentralised energy networks. So, having led industry groups in exploring forestry harvesting (where timber waste from pulp and paper plants and sawmills becomes fuel), HAUC is now assisting regional businesses. One beneficiary is Stafford's Talbott Heating, whose recently introduced biomass-fuelled BG25 CHP unit scored a world-first, with its continuous turbocharged operation, based on a self-sustained generating cycle fuelled by combustible recycled wood pellets. Talbott is now the leading UK-producer of biomass-fuelled equipment for heating and power.

Meanwhile, Aston University recently strengthened its position in bioenergy research with new chemical engineering laboratories for the University's European Bioenergy Research Institute (EBRI). Focusing on biomass conversion, EBRI's bio-thermal valorisation of biomass (BtVB) pyrolysis process uses a pyroformer reactor combined with a fluidised bed gasifier to take a wide range of feedstock. This includes municipal and agricultural organic wastes, as well as wood, sewage, sludge and construction waste otherwise sent to landfill.

In operation, a 'smart' conveyor detects the type of feedstock, adjusting reactor times accordingly. The approach offers a potential world lead for cities such as Birmingham, which could encircle its conurbation with strategically located BtVB-based plants consuming hundreds of thousands of tonnes of organic waste, and then delivering CHP, as well as autogas for vehicles, and biochar-based fertiliser as by-products.

Aston is also managing a £6.2m bioenergy project, with 14 research organisations and nine industrial firms, to deliver a UK centre of excellence in bioenergy and biofuels. A further €3.73 million project is researching a new biofuel generation to reduce fossil diesel imports, while another £3m collaborative project with Delhi's Indian Institute of Technology is focusing on developing mini power plants. Powered by renewable and waste sources, these could overcome unreliable energy supplies in rural India and help end fuel-poverty there.

Low Carbon Research Centre
Moving on, neighbouring Birmingham City University's Centre for Low Carbon Research (CLCR), in the Faculty of Technology, Engineering and the Environment, is continuing its work on transportation, bioenergy and intelligent buildings. CLCR's facilities include a research-based EnviroLab and engine test-cells, currently being used for automotive powertrain and biofuel research. For example, the team is supporting Morgan's advanced LIFECar powertrain development and a dual-fuel programme for heavyweight diesel engines running on biogas

This university's biofuels research has proved a stepping stone into wide-ranging environmental research, including bioenergy generation. For instance, CLCR is developing an approach that incorporates CO2-absorbing algae as part of a revolutionary self-sustaining anaerobic digester-based biogas production process. Algae will be cultivated on nutrient rich anaerobic digester plant wastewater in a photo-bioreactor (PBR), which provides controlled growth conditions. Anaerobic digester-generated biogas then fuels electricity-generating CHP engines, one of which heats both the digester and the PBR processes.

Meanwhile, the algae is harvested and broken down, releasing oil for biodiesel production for transport and CHP plants. Remaining algae cells can then either be fermented to produce bioethanol or recycled into the anaerobic digester, producing more biogas. Bear in mind that biogas can be channelled into the UK's gas grid, or compressed for transport or CHP generator fuel. Several CLCR research programmes focus on the algae-based processes, with involvement from partners including: ORA (Organic Resource Agency), an authority in organic waste segregation and recycling; Varicon Aqua Solutions, which specialises in closed PBR algae-cultivation systems; and Enpure on the anaerobic digestion side, covering ultrasonic cavitation technologies for water and wastewater treatment.

CLCR also organises a biofuels special interest group, with members including feedstock suppliers, as well as biodiesel, transesterification and other processors, plus end-users. The team is also exploring 'urban farming' alongside major food industry firms, with a goal of turnign brownfield sites to accommodate large multi-level greenhouses for intensive crop growth, either for consumption or biomass production.

In the future, biomass generated in this way will feed anaerobic digester plants producing biogas to fuel CHP generators, in turn able to power both the process and its surrounding infrastructure. CHP-generated CO2 would help nurture the greenhouse crops in a self-sustaining environment that also involves minimal transport.

Lynsey Melville

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