Building works

Applying energy-saving technologies to buildings would bring the biggest single reduction in the CO

emissions of major cities, while slashing hundreds of millions of pounds from energy bills, according to a major new study focusing on London.

A research project carried out for engineering giant

suggests that transforming the energy efficiency of domestic and commercial premises dramatically outstrips higher profile technologies such as wind power in terms of the benefits versus costs involved.

Measures such as insulation, energy-efficient lighting and boilers, and sophisticated building automation systems could between them reduce London's emissions by one third by 2025 according to consultant

, which compiled the report.

At the same time as they are cutting greenhouse gases, the energy saving measures would more than pay for themselves by delivering significant cost reductions. The study claims energy-efficient lighting alone would cut around £135m a year from the UK capital's energy bill by 2025.

Unveiling the findings, McKinsey director Jeremy Oppenheim said the figures show how relatively straightforward measures can put 'fashionable but expensive' technologies in the shade — at least when applied to major conurbations.