The bird's eye view
May 1st 2008

The job of managing energy can be reduced to four primary classes of activity: a) Reducing cost per unit b) Preventing foreseeable waste c) Detecting and correcting unexpected waste d) Increasing underlying efficiency Figure 1 shows how they relate. The main objective is to save money (hence the inclusion of item a) but items b, c, and d will result in carbon emissions being reduced as well and can bring other benefits: Relieving constraints on supply capacity Extending the life of equipment by avoiding idle running Reducing replacement costs of boilers, chillers and air compressors Reducing the cost per unit This activity covers procurement of energy at the most favourable price, and subsequent invoice checking (some companies outsource these activities to specialist bureaux). There may also be scope to minimize electricity transportation charges, notably by changing work patterns to even out the daily profile of electricity consumption improving electrical power factor to minimise the current drawn for a given amount of useful power These are actions which the works engineer can and should get involved with.

Preventing foreseeable waste Poor maintenance and careless operation of equipment can cause energy waste.

Some common examples would include equipment being allowed to run idle, and burners being allowed to go out of tune.

The former can be addressed by raising workforce awareness and motivation levels, while the latter is a question of vocational training for maintenance staff (complemented by energy-aware maintenance specifications). Motivation, training and awareness campaigns, combined with effective routine inspection regimes, are the main line of defence against the 'foreseeable' category of energy waste. Nor is it just a question of people doing their jobs in a more energyeffective way: higher staff awareness levels can lead to a higher reporting rate for steam leaks and other causes of loss.

Detecting and rectifying unexpected waste Although staff vigilance, routine inspections and spot audits will pick up many causes of waste, there are hidden losses as well. Examples could include frost-protection heaters running when not required, malfunctioning non-return valves and steam traps, drain valves left open, worn impellers on pumps, losses from idle boilers on a range, failed time control on heating and ventilation equipment… If it can go wrong, it will, and it will cost you.

The defence against unexpected random hidden excess costs is a technique called 'monitoring and targeting' in which every metered stream of consumption is assessed once a week (say) in terms of the difference between actual and expected consumption. 'Expected' consumption should if possible be calculated by reference to production throughput, weather, mileage, or other 'driving factor', the relationships having previously been determined by analysis of past performance.

Increasing underlying efficiency Finally we come to 'spend-to-save' projects.

Opportunities for these are usually found through an energy survey. Although energy surveys are commonly carried out by expert consultants, you can also do your own. The Carbon Trust, a government agency, publishes Good Practice Guide 316: Undertaking an industrial energy survey to help works engineers spot opportunities for themselves. Consultants' survey reports can sometimes offer too many recommendations, so if commissioning one, stipulate that you just want one or two sure-fire big hits (but properly evaluated). You may need to forego grant assistance to get a wellfocussed report, but it will be worth it not to be paralysed by a bewildering array of vague possibilities.

Where next? Every reader will have different emphases they want to apply, depending on their circumstances, their roles, and their expertise. But for what it is worth, this is roughly the order of play if you are just starting out: 1. Buy energy competitively, check the bills scrupulously, and look for opportunities to cut electricity transportation charges 2. Get your data collection sorted out (maybe add a few extra meters) and establish a simple but effective monitoring and targeting scheme (see www.vesma.com/mt) 3. Mobilise everyone through a motivation and awareness programme, and if necessary arrange vocational training for key individuals (see www.nifes.co.uk/training) 4. Survey your factory and implement at least one significant sure-fire spend-tosave project.

The author is a former energy manager and now senior consultant with NIFES Consulting Group and a director of Degree Days Direct.

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