Power moves

With the UK in the midst of one of the coldest winters in recent years, the question of securing the country's future energy supplies is not far from everyone's mind. The past year has seen a resurgence of conflict over Russian gas supplies, with flow through Ukraine being cut, leaving countries in Eastern Europe without power.

There are fears that as Britain becomes more dependent on gas as an electricity-generation source, such problems could have a future impact here unless alternative means of generation are found.

Natural gas accounted for 43 per cent of UK electricity production in 2007, up from 36 per cent the previous year, although most of this is still sourced from the North Sea.

One method of creating more energy from the same amount of raw material is the use of Combined Heat and Power (CHP) systems, which simultaneously generate usable heat and power — usually in the form of electricity — in a single process. Because CHP systems make extensive use of the heat produced during the electricity generation process, they can achieve overall efficiencies in excess of 70 per cent at the point of use. In contrast, the efficiency of conventional coal-fired and gas-fired power stations, which discard this heat, is typically around 38 per cent and 48 per cent respectively at the power station. Efficiency at the point of use is lower still because of the losses that occur during transmission and distribution.