Energy Efficiency



Energy efficiency measures can play a part in reducing both energy demand and greenhouse gases. At present, only about one-third of the energy content of the fuel we use emerges as ‘useful’ energy, the remaining two-thirds ends up as waste heat. One reason for this is that energy gas been reducing in price over the past century, so there is little incentive to reduce costs by increasing efficiency.

There is a large potential for improving the efficiency of electricity generation by the application of new technology. One example is the combined cycle gas turbine (CCGT) which uses the hot exhaust gases from a gas turbine generator to power a steam generator which then produces additional electricity. This results in efficiencies of 50 per cent or more. Another example is the use of waste heat from power stations to directly heat buildings This process, called combined heat and power (CHP), is widely in use in Denmark where around 72 per cent of electricity was produced this way in 2000.

There is also a large potential to increase the efficiency of energy use on the demand-side. The technological approach is to improve the efficiencies of the appliances we use so that we use less energy to achieve the same service levels. The social approach involves rearranging our lifestyles so that we use less energy, e.g. by walking or cycling instead of driving to work.

Another way to reduce energy usage is to reduce the material used in products as diverse as car bodies and drink cans.

The royal Commission on Environmental Pollution (RCEP) has come up with four scenarios for the UK which consider the options available for balancing supply with demand given the need, as suggested by various reports, to reduce CO2 emissions by 60 per cent. The scenarios focus on the reduction of demand and the use of renewables, perhaps in conjunction with cleaned-up fossil or nuclear plants.

The overall message is that there is a number of paths to sustainability, but, since they rely on different mixes of technology, they are likely to have a different social, environmental and political implications.

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