Changing the colour of night on urban streets - LED vs. part-night lighting system

Many cities in the United Kingdom are upgrading the streetlights to white light-emitting diode (LED) lamps for reducing the electricity costs and attaining the sustainable energy solutions. Installation of LED lamps on urban street requires higher installation costs and a long-term period to payback benefits of replacing outdated streetlights in terms of energy savings and costs. To achieve the short-term energy efficiency of urban street lighting, city councils sometimes adopt the part-night lighting system particularly in the residential areas. The Coventry City Council recently replaced 29,701 existing sodium lights with LED lamps. This paper performs the economic analyses to understand the feasibility of two street lighting systems: LED lamps and ‘part-night’ lightings on the Coventry streets during the twenty-year period assuming the return period of investment is twenty years. The projection of energy consumption and costs for LED lamps and part-night lighting systems shows that electricity can be saved by 44% and 21% comparing to current electricity usages, respectively. Considering the budgetary constraints of Coventry City Council, this paper concludes that the part-night lighting system may be beneficial in short-term period, but it is economically feasible to replace the existing lower efficiency lights with LED lamps.