Postgraduate Study

Fossil fuels represent the principal global source of energy accounting for approximately 80% of world energy consumption and 90% of UK energy demand in 2006.  Fossil fuels are an attractive energy source because they are associated with high energy densities and are easy to transport and handle compared with other energy sources such as biomass. However, fossil fuels are considered unsustainable because they are a finite resource and are detrimental to the global environment, being the principal source of UK carbon dioxide emissions, accounting for 586 million metric tons of carbon dioxide emissions in 2006.  There is a need to investigate the viability of other alternatives for energy generation.

The two main sources of biomass for energy generation are purpose-grown energy crops and waste materials. Energy crops, such as Miscanthus and Short Rotation Coppice, are cultivated mainly for energy purposes and are associated with the food vs fuels dilemma, which is concerned with whether land should be used for fuel rather than food production. The use of residues from agriculture, such as straw, for energy generation circumvents the food vs fuel dilemma and adds value to existing crops.

An example of an agricultural residue that could be used as a fuel for energy generation is oilseed rape (Brassica napus) straw . In the UK, the total area of OSR harvested increased between 2000 and 2008 from 332,000 ha to 598,000 ha, respectively, representing 12.6% of the total crop area (DEFRA, 2009). Currently there is not a significant market for oilseed rape straw in the UK, and a large proportion of it is chopped and incorporated into the soil through ploughing. Consequently development of a market for oilseed rape straw would add value to the gross margin of the crop at farm level.

But, straw exhibits a low bulk density which makes its transport more expensive than the transfer of natural gas or petroleum.  Reducing the cost of collection, transport and storage of biomass through densification is thus critical to developing a sustainable infrastructure capable of working with significant quantities of raw material.

The project main objectives are:

1) Investigate whether storage of OSR straw and OSR straw pellets affects the chemical, biological, physical and combustion properties of the biomass.

2) Understand the mechanical behaviour of OSR straw under compression to high density materials.

3) Assess whether OSR straw pellets present a suitable and economically viable alternative to traditional fuel.

Research video:

Chico-Santamarta, L., Humphries, A.C., White, D., Chaney, K., Loynes, J. (2008). Durability of agri-waste pellets in storage and handling. Poster presentation in the UKERC Annual Assembly/Energy Summer School.

Chico-Santamarta, L., Humphries, A.C., White, D., Chaney, K., Godwin, R.J. (2009). Effect of pre- and post-pelletisation storage of canola (oilseed rape) straw on the quality and properties of pellets. ASABE Annual International Meeting. Paper number 096105, Reno, Nevada, June 21 - June 24, 2009.

Chico-Santamarta, L., Richards, T.E., Godwin, R.J. (2009). A laboratory study into the mobility of travelling irrigators in air dry, field capacity and saturated sandy soils. ASABE Annual meeting, Paper number 096106, Reno, Nevada, June 21 - June 24, 2009.

Chico-Santamarta, L., Khodier, A., Chaney, K., Godwin, R.J., Humphries, A.C., Kilgallon, P., Simms, N., White, D. 2010. Ash deposition studies using Oilseed Rape Straw Pellets in a Pilot-Scale Combustor, Energy from Biomass and Waste Conference, London, UK.

Chico-Santamarta, L., Humphries, A.C., White, D., Chaney, K., Godwin, R.J. 2010. The effect of Storage on the quality properties of Oilseed Rape straw pellets. European Pellet Conference, World Sustainable Energy Days, Linz, Austria. Poster presentation.

Chico-Santamarta, L., Humphries, A.C., White, D., Chaney, K., Godwin, R.J. 2010.  The use of oilseed rape (Brassica napus) straw for combustion purposes: a review of the advantages and disadvantages.  Aspects of Applied Biology, 101, Non Food Uses Of Crops.

Chico-Santamarta, L., O'Dogherty, M., Underhill, T., Humphries, A.C., White, D., Chaney, K., Godwin, R.J. (2010). Preliminary work on the compression behaviour of canola straw to high density products. ASABE Annual International Meeting. Paper number 1009975, Pittsburgh, Pennsylvania, June 20 - June 23, 2010.