Over the past few years it has become fashionable to embrace the concept of microgeneration, that is, generating electricity on a small scale with the aim of using less from the national grid. A roof-mounted wind turbine, for instance, has become de rigueur for many politicians wanting to boost their green credentials.

Sceptics argue that microgeneration is merely a niche market that is unlikely to contribute much to greenhouse gas reduction efforts. Critics say the technology currently available to households is expensive and not suitable for every location: micro wind turbines can be ineffective in sheltered, urban areas while solar panels need large amounts of sunshine to be cost-effective.