Energy saving potential of office equipment power management

The potential for energy reduction in UK commercial offices through effective management and behaviour change

“…The power down rate at location A increased to 79% from 72% while at location B the power down rate increased to 83% from 70%, these rates compares favourably with the findings of Kawamoto et al (2003) who observed power down rates of 80-97% in air conditioned Japanese office buildings, although further improvements may still be possible. Furthermore it would appear that 46% of users at location A and 56% of users at location B have removed any additional items overnight (mobile chargers, fans, heaters etc) and potentially unplugged computers and screen as readings of below 0.8watts (Monitoring device draws 0.8 watts) were observed on a regular basis.…”

“…However it has previously been established that energy use of desktop equipment is highly influenced by occupant behaviour and is flexible in nature (Zhang, Siebers & Aickelin, 2011). This view is supported by a study by Kawamoto, Shimoda and Mizuno (2003) which estimated that for an average working day the actual in-use utilisation of desktop equipment may commonly be as low as 43%. Additionally many office workers don't power down equipment at the end of the working day (Berl & de Meer 2011) and even fewer unplug equipment that may still draw power when turned off.…”

“…From this it was found that during the baseline monitoring period 72% of work stations at location A and 70% at location B powered down overnight. The identified power down rate is significantly less than that found by Kawamoto et al (2003) which observed power down rates as high as 80-97% in Japanese offices spaces Conversely a similar US based study found power down rates of just 36% (Roberson et al, 2006). Coupled with the initial findings of this study bringing UK power down rates in-line with those observed in the Japanese study could offer significant savings, however there is a risk that without interventions more energy could be wasted as demonstrated in the US study.…”

“…While the monitoring and feedback mechanisms are important, procurement also has a part to play. As discussed previously, laptop computers generally use less power than traditional desktops and have been observed to result in increased overnight power down rates (Kawamoto, et al 2003). Automatic shutdown software programmes are commercially available and as demonstrated by James (2010) can contribute to energy use reductions as part of a wider savings strategy targeting unregulated energy use.…”

“…The average power density during working hours at office A was 25.2 watts while at office B this was slightly lower at 22.2 watts (see watts, on site measurement) but the power down rate of laptops tends to be in excess of that of personal computers (Kawamoto, et al 2003) reducing the corresponding overnight wastage.…”