Potential biomass use in the UK

In the UK, the total energy consumption in 2006 was 232 Mtoe with the consumption of gas at 89.2 Mtoe and coal 43.4 Mtoe (Fig. 1.4). Both gas and coal are used to gener­ate electricity and it is these two fuels that biomass may replace. An estimate of the possible biomass available in the UK is given in Table 4.8. A total of 7 million t of biomass represents an energy content of 0.149 EJ as 1 t of biomass represents19 GJ. This constitutes 1.53% of the total energy consumed in the UK. If the biomass is con­verted into electricity at an efficiency of 30%, it would generate 9.8 TWh. The UK electricity use is 346.4 TWh and therefore 9.8 TWh represents 2.83% of total demand.

In another study the potential of a mixture of energy crops and forestry and straw wastes combined with a conversion of grassland to produce electricity was determined (Powlson et al., 2005) (Table 4.9). The mixture of energy sources was capable of producing 12.2% of the electricity required from 7.43 Mha, some 40% of agricultural land. In contrast it has been suggested that 2.7 Mha would be required to produce 100% of the UK’s electricity (Rowe et al., 2009).

Table 4.8. The available biomass in tonnes dry material in the UK. (From Woodfuel, 2007; www. woodfuel. org. uk)

Source

England

Scotland

Wales

Total

Forest and woodland

2,394,147

2,942,513

971,689

6,308,349

Thinnings

616,060

34,717

19,706

670,483

Short rotation coppice

15,899

572

218

16,689

Waste

289,686

403,538

165,783

858,901

Total

3,315,686

3,381,340

1,157,396

7,854,422

Table 4.9. Potential electricity from biomass. (Adapted from Powlson et al, 2005.)

Process

UK electricity (%)

GWh

80% set-aside (611,000 ha in 2002)

2.7

9,282

50% sugarbeet converted to biomass (169,000 ha)

0.5

1,719

50% forestry waste

1.6

5,501

50% wheat straw (19 Mt, thus 8 Mt from 2 Mha)

3.7

12,720

10% grassland converted to biomass 6.65 Mha

3.7

12,720

Total

1 2.2

41,943

Electricity demand 343.8TWh (343,800 GWh), 1.237 EJ. Electricity generation at 1.6 MWh/t, 12 t/ha and efficiency of 30%.