ABSTRACT
The concept of generating energy from ingredients that are already being produced in the countryside is a compelling one, and it seems indeed to embody the whole principle of renewables in that it uses crops that can be regrown once harvested and which will furthermore be absorbing carbon dioxide while doing so. Organic waste materials can also be part of an ongoing cycle, producing combustible gases and fertiliser when treated in a digester. Crops that are specifically cultivated for generating energy as either heat or power are sometimes described as ‘dedicated’ biomass, whereas waste materials and by-products, which include cereal straw and timber residues, are defined as ‘dependent’. This chapter deals with dry materials which comprise predominantly woody coppice or miscanthus. Organic waste and related materials are covered in the following chapter under the heading of Anaerobic Digestion, and a further format, with crops being converted into road fuels, is considered in Chapter 7.
