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Bioenergy

Projects supervised by: Professor Piers Forster, Dr Andrew Ross, Professor Paul Williams, Professor William Gale, Dr Miller Alonso Camargo Valero, Professor Jenny Jones, Professor Alan Williams and Dr Leilani Darvell.

Researchers: Robert Bloom, Ramzi Cherad, Ben Dooley, Harriet Fletcher, James Hammerton, Paula Mcnamee, Eddy Mitchell, Douglas Phillips, Aidan Smith, Philippa Usher, Jayne Windeatt

Bioenergy is the term used to describe the energy stored in plants which it derives from photosynthetic processes. It encompasses biomass, biofuel and biochar technologies. These processes convert sunlight into plant material, storing the sun’s energy within chemical bonds, providing a renewable source of energy. Bioenergy aims to be ‘carbon neutral’, meaning the carbon absorbed from the atmosphere during the growth phase equals the carbon emitted during processing and combustion, so there is no net increase in atmosphere CO2. Research with biochar also considers possible carbon sequestration properties which could potentially remove even more CO2 from the atmosphere.

There are a variety of energy crops, from traditional food crops to waste products including food wastes and agricultural residues. Bioenergy as a fuel source can be used across several energy sectors including heating, electricity, agriculture and transport fuels. It is also easier to integrate bioenergy into existing fuel production and distribution infrastructure than other new technologies.

The DTC and Bioenergy

The research carried out at the DTC in this area is diverse. It encompasses optimising techniques for combustion of biomass, use of algae and plant crops to create a liquid biofuel as well as introduction of biochar to soil to enable carbon sequestration.

Torrefaction, also known as ‘mild pyrolysis’ or ‘roasting’, is a process where the biomass is heated in the absence of air for around 60 minutes between 250°C-300°C. Mass loss of around 30% occurs during the process but energy retention is 90% creating an increased heating value more comparable with coal. Torrefied biomass is also more hydrophobic (repels water). These improved characteristics not only improve the biomass itself but improves handling and logistical issues too.

Work on production of algal biofuels looks into optimum conditions for biodiesel production from microalgal oils and recycling of gasification process water, to be used as a media for macroalgal growth. In addition research is being carried out in collaboration with a university in north east Brazil which analyses the existing biodiesel production process along with challenges from an environmental, economic, technical and social point of view. Lifecycle assessments of both processes will demonstrate the relative carbon balance of using both macro and micro algae as a biofuel feedstock.

Carbon sequestration using biochar from agricultural waste is being assessed using a number of approaches. This data from Experimental pyrolysis of different agricultural wastes is then being used for the development of four future scenarios of biochar production for future emissions and land-use to 2100. These will then be used to investigate the wider effects of biochar addition to soils on the carbon cycle and climate. This includes assessment of a possible reduced CO2 fertilization effect, altered albedo, increased net primary production (NPP) and other possible feedback mechanisms.

As the UK has begun to make an effort to reduce greenhouse gas emissions like CO2, the focus is on developing an alternative to fuels like gas and coal which are known as fossil fuels. Fossil fuels have accumulated carbon from the earth over millions of years and burning this carbon increases the amount of CO2 in our atmosphere. Biomass is a renewable energy resource because it traps CO2 from the atmosphere. We then process the biomass for fuel releasing the same CO2 back and therefore not adding extra CO2 to the atmosphere. The word biomass can describe corn, wheat, sugarcane, straw and wood. These are being utilized for power generation and in the production of bio-oil for transport. Biomass resources also include biomass from the sea (seaweed) and these are being investigated because they do not compete with food production unlike corn and wheat. Bioenergy will have an increasingly important role to play in the future, as energy demand continues. At the same time, global demand for other resources continues, most importantly food and water, and so energy production technologies must limit competition with these.