Energy reduction

Using technology to identify savings

Last year, our energy reduction programme cut our energy bills by £325,000.

How did we do it? By applying our own lean thinking to our operations, primarily through a set of tools and processes we created to monitor and intervene in the operation of our sites. Though only a year old, the gains achieved so far provide an encouraging foundation – and a template that others can copy.

We anticipate even better results this year.

Making sense of electricity consumption

While we have taken action in a number of areas, including progress in reducing our gas and water requirements, our main focus has been on identifying ways of reducing our electricity consumption.

While cutting electricity use sounds simple, historically organisations have found it difficult to map and understand their energy use with sufficient detail to be able to set meaningful targets for savings and link them to concrete energy saving measures. The problem, of course, is that patterns of energy usage disappear in the bottom line: your electricity bill can't directly tell you that, for example, your air conditioning system is being used unnecessarily.

To solve the problem, we invested in smart electricity meters that collect usage data every 30 minutes, allowing sophisticated mapping and analysis of sites over time. This has enabled us to identify a range of potential savings, such as lighting left on too long or air conditioning units repeatedly switching on and then powering down during the night.

The cumulative impact of these savings can be enormous when you appreciate how much power many offices use even when empty. For example, our peak use rate is 18 MW – the equivalent of 18,000 one-bar electric fires. Crucially, however, our baseline electricity use – when the offices are empty – is 12 MW. Clearly, then, there is a significant amount of energy being used at times when our buildings are largely empty, some of which must be superfluous.

In May 2006, therefore, we set a target to reduce our energy use by 10 per cent across our non-data centre estate. The figure was based on analysis that suggested that between 5 per cent and 20 per cent of energy was being wasted across our office sites. Initially, we excluded data centres from this initiative in the belief that changing human behaviour would be quicker and easier than modifying the operating environment for the equipment serving our customers. In the event, however, we have also been able to make significant changes in the data centres.

We did it by challenging two time-honoured assumptions about operating conditions in data centres: that temperature and humidity levels must be maintained at certain levels. Data centres, for examples, are generally managed to provide a steady room temperature of 21 or 22 degrees Celsius. This requires constant use of cooling equipment, which turns these sites into massive refrigerators expelling heat into the outside air, with considerable cost to both the business and the environment.

On investigation, we found that there was absolutely no technical reason why the average temperature can’t be raised by one or two degrees without affecting performance.

Similarly, data centre managers have traditionally worked to a target of 50 per cent relative humidity. This is to reduce the build-up of static electricity, which, when discharged by a machine's casing, could cause it to fail. Our teams found that 35 per cent relative humidity is a perfectly adequate operating level – especially as today's sites have removed static-friendly carpet tiles in favour of insulating vinyl.

The cumulative effect of raising the average temperature to 23 degrees and the relative humidity to 40 per cent at one of our data centres resulted in recurrent annual savings of £12,000 which equates to a 2.4% reduction in costs.

It’s a saving that points the way to significant potential savings elsewhere in our data centre estate, as well as a clear illustration of the ability of small efficiencies generated by waste elimination to produce significant lifetime benefits.