Friday, July 13, 2012

Decentralised Energy

Electricity production in the UK is responsible for a third of our carbon emissions. This is the UK’s single greatest contribution to climate change. It need not be so. Our centralised model of production and transmission wastes an astonishing two-thirds of primary energy inputs, requiring us to burn far more fuel and emit far more carbon dioxide than necessary. It is hard to imagine a more wasteful and inefficient model than that which currently services the economies of the ‘developed’ world. In our existing system, electricity is produced in a small number of large power stations, and then distributed to where it is needed. Because the power stations are generally far from centres of demand, much of the heat which is produced when fossil fuels are burnt is not used, but vented up chimneys or discharged to rivers. This heat loss alone represents a wastage of over sixty percent of the total energy released by burning the fossil fuels. Further losses occur as the electricity travels along the wires of the transmission and distribution systems.

In total, the energy wasted at the power station and on the wires is equal to the entire water and space heating demands of all buildings in the UK – industrial, commercial, public and domestic. This is a nonsensical way to run our economy and power our lives. But there is an alternative. In a decentralised energy (DE) system, electricity would be generated close to or at the point of use. Buildings, instead of being passive consumers of energy, would become power stations, constituent parts of local energy networks. They would have solar photovoltaic panels, solar water heaters, micro wind turbines, heat pumps for extracting energy from the earth. They might also be linked to commercial or domestic operated combined heat and power systems. The massive expansion in renewable capacity that this would represent, and the fact that when fossil fuels were burnt the heat would be captured and used, would lead to dramatic reductions in overall carbon emissions – at least half of all emissions from the power sector, or 15% of total UK emissions. This radical transformation of our energy system sounds attractive but expensive. But in fact decentralising our energy sources, instead of replacing our current centralised system, may actually save money in the long run. A centralised network of cables is an old technology – and a phenomenally expensive one at that. New low-carbon technologies dictate a different infrastructure. According to the International Energy Agency, the European Union will spend $648 billion on modernising and replacing the transmission and distribution networks. The opportunity to avoid many of these costs means that decentralised energy makes economic as well as environmental sense. Decentralised Energy (DE) also offers a way forward for developing nations and for the emerging economic giants like China and India. It is sometimes claimed, fatalistically, that efforts to stabilise the climate will be overwhelmed by China burning its coal reserves. But developing a decentralised energy system in response to its growth in demand for power would enable China to reduce associated carbon emissions by 56% as compared to the centralised scenario – and costs would be reduced by 40% as well. Unfortunately, the debate in the UK has focussed more on whether we need a new generation of nuclear power stations. Nuclear power is the epitome of centralised, outdated electricity generation. Replacing existing nuclear stations with new ones would perpetuate the centralised system, entrenching all the costs and inefficiencies that implies. Such inefficiencies currently waste three times as much energy as would be contributed by new nuclear power stations. It is only because of technological apathy – failure by government and industry to invest in real innovative alternatives – that nuclear power is given any serious consideration.

Decentralising energy offers a compelling alternative vision, in which we can both combat climate change and roll back the nuclear threat. To give just one example of the potential, if half the houses in the UK were provided with domestic combined heat and power units, which is technically feasible, then the electricity generated would replace the entire nuclear capacity we have today.


OUT OF 100 UNITS OF FUEL, THE POWER STATION WASTES 61.5%. THE TRANSMISSION LINES WASTE A FURTHER 3.5% AND HOMES ACCOUNT FOR 13%. JUST 22% OF THE ENERGY PUT IN TO THE SYSTEM IS ACTUALLY USED.

This article has been taken from the Greenpeace report called Decentralising power: an energy revolution for the 21st century.

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