As already mentioned, wood is still extensively used as a major source of fuel in poorer countries. If more wood is used than is replaced by additional growth this can lead to desertification. It is therefore desirable to replace wood by more efficient and less damaging fuels, and certainly the use of wood cannot hope to solve the energy crisis in the developed countries.
Biomass in general is an organic material that can be burned to produce heat or allowed to decay and emit natural gas. In the form of wood and animal dung this has been done for centuries. In modern terms it is taken to mean use of the by-products of agricultural processes and the cultivation of plants or trees for the specific purpose of generating heat, and hence electricity. It is sometimes said that this does not add to global warming since the carbon dioxide produced when it is burned equals the amount absorbed by the photosynthesis that originally produced it. However, the House of Lords Select Committee report on 'EU strategy on Biofuels': from 'Field to Fuel' pointed out that 'carbon savings are affected by agricultural practice, production and processing methods and transportation of the feedstock'. They concluded that 'although biofuel use produces less carbon dioxide emissions than use of fossil fuels this may be partly, if not wholly, negated by environmental costs in their country of origin and by transportation to the point of use.
An example of the former is the use of the straw remaining after corn is harvested. If this were all burnt it could provide as much heat as 2% of Britain's oil imports. As straw is cumbersome to transport, it is best burnt on the farms, and many farmers have installed straw boilers. The heat generated can be used to heat farmhouses and animal buildings and to dry grain and hay. However, the straw-burning boilers are expensive and require automatic stoking machinery. Most farmers prefer to burn it in the fields, where it fertilises the soil and kills weeds and insects. In Brazil the bagasse remaining after the sugar cane has been crushed is often burnt to heat the water used to purify the sugar or in gas turbine systems to produce electricity. Sweden and Finland obtain about 30% of their electricity from biomass, mostly from their forestry and paper-making industries.
Experiments have been made to determine the practicability of planting trees that are subsequently burnt. Willow is very suitable for this purpose, as it grows rapidly. The process has been found to be uneconomic, and it also uses up agricultural land.
In many countries, especially developing ones, there is a serious and growing shortage of food. Dominique Strauss-Kahn, the head of the International Monetary Fund, recently said that 'hundreds of thousands of people will be starving', and that 'children will be suffering from malnutrition'. 'He predicted that increasing food prices would push up the cost of imports for poor countries'. Since January 2007, the price of wheat has risen two and a half times and that of rice has almost trebled. These are staple foods in many countries, and the rising prices bear heavily on the poor. The sharp rise in food prices is due to increased demand, poor weather and an increase in the area of land used to grow crops for more biofuels. Of these, biofuels derived from soya beans, sugar cane and corn have been identified as the major cause. The food shortage and rising prices have led to riots in Egypt, Haiti, Bangladesh, India and several other countries. Professor Beddington, the British Government's Chief Scientific Adviser, has said that 'it is very hard to imagine how we can see the world growing enough crops to produce renewable energy at the same time meet the enormous demand for fuel' (Daily Telegraph, 14 April 2008). The food shortage could be considerably reduced by increased use of genetically modified crops, but these still encounter severe opposition.
The current massive switch from food production to growing crops for fuel forces us to answer the question: Do we really want people to starve so that we can continue to drive our cars? Thus according to the World Bank the price of food has risen by 80% in the three years to 2008, due to shortages of supply and rising demand, pushing 100 million people below the poverty line. This has partly been blamed on the USA and European Union for encouraging the conversion of corn to ethanol as an alternative to petrol. The European Union plans to use this for 50% of its transport fuel by 2010, and large increases are also planned in the US. However, it failed to reach its 2% market share target in 2005, but still aims for 5.75% market share by 2010 and 14% by 2020. The difficulty is that 'biofuels in Europe are expensive, between 30 and 45 p/litre whereas biofuel made from sugar cane costs 6-11 p/litre in countries such as Brazil that has higher crop yields and lower costs for land and labour' (Nuclear Issues, May 2007). A large-scale expansion of biofuel production also affects 'soil fertility, water availability, pesticide and fertiliser use'. The committee of the House of Lords already mentioned concluded that: 'Tropical rain forests act as a carbon sink: burning, logging and then ploughing it leads to very significant carbon emissions, so any potential benefit from growing cheaper renewable feed stocks on such cleared rain forest would never repay the carbon debt that you had built up by clearing it in the first place'.
The growth of biofuels requires large areas of land. Thus assuming that it gives 1.45 tonnes of fuel per hectare 29.5 million hectares would be needed to supply transport fuel for the UK, whereas the total available agricultural land is 5.7 million hectares. As James Lovelock has remarked, 'biofuels are potentially dangerous and if exploited on a large scale would lead to disaster' (Nuclear Issues, January 2007).
Biomass can also be used as an additional fuel in coal power stations. It is planned to adapt Britain's largest coal-fired power station, Drax, to burn every year about 1.5 million tons of biomass, such as olive stones and sunflower seed husks, together with the coal. It is estimated that this will reduce carbon dioxide emissions by 15%.
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