Sunday, October 28, 2012

Decentralised Energy: Woking Council Case Study

Woking Borough Council has pioneered a network of over 60 local generators, including cogeneration and trigeneration plant, photovoltaic arrays and a hydrogen fuel cell station, to power, heat and cool municipal buildings and social housing. Many town centre businesses are also connected to this local energy supply. The Woking energy model produces dramatic savings in energy use and greenhouse gas emissions. With further help from energy efficiency measures, the council has reduced CO2 emissions associated with the operations of its own estate, including social housing, by a staggering 77% over just 15 years. Some sophisticated engineering solutions have been deployed, including large thermal stores in the town centre car park and at the leisure centre at Woking Park. The balancing of the system is performed entirely by computer, and the control system can be readily accessed by remote engineers or council officers.

The generators are connected to users via private electricity wires owned and operated by Thameswey Energy Ltd – a company set up and partly owned by Thameswey Ltd, a municipal energy and environmental services company itself wholly owned by Woking Borough Council. These private wires have points of connection to the local distribution networks (in turn connected to the national grid), but in 2003 the council’s electricity infrastructure was 99.85% self-sufficient. In the event of a grid power cut the system can switch to island generation mode, meaning businesses and householders connected to the private wires continue to be supplied with electricity with only a short interruption while the system disconnects from the dead grid and restarts using a small black start generator (a generator which can start up with no external power input).

Woking was able to raise capital for energy infrastructure development initially through energy efficiency savings. A fund mechanism was established in a benchmark year for energy expenditure, against which savings accruing from energy efficiency measures were recycled, year on year, into further energy-saving initiatives. The substantial financial savings allowed the council to invest millions in energy supply innovation. Moreover, Thameswey Energy Ltd has attracted investment from Danish pension companies who recognise the steady low-risk return the initiative offers – energy systems like Woking’s are a common component of investment portfolios for pension and insurance companies across Europe.

Developing a private network enabled Thameswey Energy Ltd to avoid charges usually associated with the use of the grid. By circumventing these costs, it has been able to fund wires and generation to deliver low emission electricity in competition with conventional suppliers. For domestic customers in social housing, Thameswey provides electricity below the rate of other electricity suppliers as part of Woking Borough Council’s fuel poverty programme. The council estimates that it supplies heat and power to potentially fuel-poor households for 6–7% of the state pension – well below the 10% threshold of all household income spent on heating that the Government uses to  define fuel poverty.

While the Woking model is widely celebrated in energy circles, its significance for UK energy policy has yet to be fully appreciated. It shows that renewable technologies and cogeneration are highly complementary and lend themselves flexibly to a piecemeal engineering approach as finances allow. The key lesson from Woking is that, liberated from the constraints of centralised rules and infrastructure, cogeneration and renewables can assert their own competitive potential.

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