Burning the Midnight Oil

Recent research from the Bartlett School of the Built Environment, UCL (University College London) in conjunction with Worcester Polytechnic Institute Massachusetts USA shows that leaving office lights on after working hours is potentially wasting a massive 1.4 – 1.6 TWh of electricity each year in the UK. This corresponds to close to 1 million tonnes of CO2 and is enough to light about 1.5 million homes a year!
The research, which was undertaken as part of the CaRB (Carbon Reductions in Buildings) project, examined a sample of 140 office buildings in London’s West End between the hours of 10pm and 3am in January and February this year. The fieldwork was carried out by a team of four students who analysed the research area by day and observed and recorded lights being left on during the night. These observations were used to help generate profiles to estimate total 24 hour use of lighting in office buildings in the UK.
The study exclusively looked at office buildings with other kinds of buildings such as hotels, shops or residencies within the sample area being excluded.
The hours of key observation were chosen since it can be assumed that whilst there are exceptional circumstances when some office workers may work through the night, it is realistic to say that it is extremely unlikely that many people would be working between the hours of 10pm and 3am. Nor would many offices be being cleaned or maintained during these hours. Therefore the use of full office lighting at these times would not generally be warranted.
Typically offices are only occupied for between 25-30% of the hours in a week so a small percentage of lights left on overnight and through the weekend wastes a lot of energy. This study shows that of the total lighting use in offices between 24-30% is being wasted.
There is considerable confidence in the results of this study and it is reasonably safe to say that this sample provides a typical picture of after hours lighting in the UK. It is to be expected that some localities are more wasteful, others more parsimonious. It is also possible that the overall national overnight and weekend lighting may be less but shockingly, it is believed that total energy wastage could well be higher, taking the observed patterns into consideration.
We are all surely now acutely aware of the need to reduce energy both to save money and importantly to mitigate against the real and frightening impacts of global warming. The cost of fossil fuel energy is at a premium with gas prices rising and oil now being priced in excess of a staggering $140 a barrel. Experts also estimate that this price may exceed $200 in the near future. Taking the above into consideration alongside of the results of this study, how can we justify such energy wastage from leaving office lights on? Surely it is a ‘no-brainer’ just to turn them off when they are not needed?
The potential energy and CO2 savings that could be achieved from turning unnecessary night-time office lighting off are vast. These savings could be easy to achieve through simple and cheap systems that are available to automate turning off lights when they are not required as well as through awareness of the problem.
Whilst this study currently applies to the UK it could easily be transferred to other industrialised countries such as the USA, Australia, New Zealand, Japan and those in Southern Europe where anecdotal evidence points to similar situations. Even considering other anecdotal evidence from some countries in Northern Europe which suggests that not all western countries are wasteful, imagine the huge easy win energy savings that could be achieved if we turned off out or hours office lighting all around the world!
The CaRB project is a £3million project funded by the EPSRC (Engineering and Physical Sciences Research Council) and the Carbon Trust under the Carbon Vision Buildings (CVB) programme. The Bartlett at UCL is part of a consortium of five UK Universities involved with three projects with a total of £5million of CVB funding.
For further details of the CaRB programme visit –

www.carb.org.uk

Contact Harry Bruhns – h.bruhns@ucl.ac.uk