4.10 Future prospects for bioenergy
A substantial proportion of the growth in renewable energy supply in the near future may come from increased direct combustion of a wide variety of biomass feed stocks for heat and electricity generation, plus a substantial increase in the supply of ‘first generation’ liquid transport biofuels.
In the longer term, newer biomass technologies, such as electricity from high-efficiency combined-cycle power plants or from fuel cells, and next generation liquid biofuels, could play an increasing role – but biomass might by then be overtaken in the developed world by fast-developing renewables such as wind and solar power.
A range of studies reviewed by the Imperial College Centre for Energy Policy and Technology (Slade et al., 2010) suggest that a rise from some 250 PJ per annum from bioenergy to perhaps 600 PJ by 2030 seems possible. As shown in Figure 12, the two sources suggested as having most potential for increased production by 2030 are wastes and perennial energy crops such as SRF/SRC.
In the developing countries, future demand for biomass energy is likely to be determined mainly by two opposing factors:
- the rise in overall energy demand due to increasing population
- the reduction in the demand for traditional forms of biomass due to a shift to more ‘modern’ forms.
Most projections suggest that biomass consumption will continue to rise during the next few decades, but at a lower rate than renewables in general or total primary energy. Nevertheless, it is estimated that traditional biomass will remain the sole domestic fuel for 2.8 billion people in 2030 (IEA, 2010c). It is therefore arguable that the improvement of traditional wood and charcoal stoves should be the most important technical aim in the field of bioenergy today.
In the medium term what factors are likely to increase competition for land between needs for energy and for food?
Population growth and changing diets look the most likely. It has been suggested that, after allowing for increased food production for a growing world population, as much as 400–700 million additional hectares could be available for energy crops worldwide in the year 2050, without unacceptable loss of biodiversity (UNDP, 2000). Other sources suggest a much lower figure.
The most optimistic recent forecast for the potential future contribution of bioenergy suggests over 1500 EJ per year, way beyond total current world energy. A more widely accepted figure might be of the order of 100–200 EJ of bioenergy per year. 200 EJ would represent a fivefold increase on current levels – a new contribution equal to over a fifth of present world total primary energy consumption.
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