Research led to the adoption of white light in residential roads and urban centres throughout the UK - saving 113 gigawatt hours of electricity and over £10 million in costs for 2012, and reducing UK CO2 emissions by 45.5 megatons.

Impacts

  • ESRC-funded research led to the adoption of white light in residential roads and urban centres throughout the UK. The use of white conventional lamps and white LED lighting has grown from 450,000 lighting units in 2008 to about 1,450,000 units in 2012 – a near three-fold increase.
  • The research fed into revision of the British Standard for street lighting for subsidiary roads, permitting lower illuminance white lighting.
  • In 2012 alone the changeover to white light saved an estimated 113 gigawatt hours of electricity and over £10 million in electricity costs.
  • The changeover reduced the UK CO2 emissions by an estimated 45.5 megatons per year.
  • The research was used to support current levels of street lighting, with possible impact on crime prevention and public safety.

About the research

Research led by Professor Tadj Oreszczyn and conducted by Peter Raynham at the Bartlett School of Graduate Studies, University College London, examined whether white street lighting provided a better quality of lighting than the traditional yellow or orange lighting. The research was mainly funded through the ESRC-funded 'Urban Lights' project.

A range of light sources were tested on volunteers, including high-pressure sodium bulbs and two types of compact fluorescent light sources. The research showed that the same lighting benefits as traditional orange sodium lighting could be achieved using white lighting with lower illuminance – obtaining the same recognition distance of people's faces.

Raynham's research led to the adoption of white light in residential roads and urban centres throughout the UK. With an estimated 1,200,000 white light lamps replacing the old sodium lamps (at an average energy saving of 28 megawatts for each streetlight) the changeover saved approximately 113 gigawatt hours of electricity in 2012 for UK local authorities. Reduced illuminance in subsidiary roads enabled energy savings of 30-40 per cent. Conservative consumption estimates also suggested annual reductions in carbon emissions of 45.5 megaton CO2.

The research was also used by local authorities, road safety organisations and residents to support the justification for maintaining street lighting in urban areas and extending its coverage to rural areas – likely leading to non-monetary impact in terms of reducing the fear of crime, crime prevention and public safety.