Efficient savings

Around 65% of the electricity consumed by industry in the UK is used to power systems driven by electric motors. By adopting energy efficient systems, however, the UK could save more than 24billion kWh each year.

In environmental terms, this equates to a 12million tonne reduction in CO2 emissions and a total environmental saving to society of £480million. And manufacturers would benefit directly, with savings on maintenance and repair costs added to the £550million saving on their electricity bills.

These findings are contained in the recently published report, 'Energy Efficient Motor Driven Systems', from the European Copper Institute (ECI).

On the wider European scale, switching to more efficient systems could save up to 202billion kWh, or E10billion a year in industry's operating costs. Again, in environmental terms CO2 emissions would be reduced by 79million tonnes - approximately a quarter of the EU's target under the 1997 Kyoto Protocol on climate change.

Co-author of the report, David Chapman of the UK's Copper Development Association, says: 'Modernisation of electric motor driven systems is essential in helping us to meet our national goal for CO2 emissions - that's a 20% reduction against the 1990 levels by 2010, well beyond our Kyoto commitment.

'The technical solutions for improving the energy efficiency of such systems are examined in the report. They include the already heavily promoted ones of changing to high efficiency motors (HEMs) and making more use of variable speed drives (VSDs) in systems that hitherto have operated with constant speed motors. But the report also examines how compressed air users, for example, can add to the benefits of HEMs and VSDs by improvements in compressor technology itself (multi-stage compressors, for example), or the use of more sophisticated control systems, or recovering heat for use elsewhere, and by generally improving overall system design.

Similarly, pump and fan users are advised on how to improve the efficiencies of their overall systems, in addition to the use of HEMs and VSDs. Supported by case studies, all this is eminently sensible advice. But as the report's authors themselves ask: 'If the savings potential of energy efficient motor systems is so high, why do they receive so little attention? What are the restraints preventing their implementation? And, if those restraints were removed, which mechanisms can still block the actual implementation of such systems?'

Regular readers might quibble over the first question - motor and drive manufacturers have, after all, been extolling their energy saving capabilities for some time now and their efforts have been well reported. But the report's verdict on the reasons for lack of implementation certainly echoes those suppliers' views on the market.

In general, the report finds three major barriers to the uptake of energy efficient motor systems: payback time is too long due to low electricity prices, there is a reluctance to change a working process and split budgets.

As most vendors will argue, energy efficient motor systems in general have reasonable to very good payback times, but many companies take a different view. The report says this is because their economics are based on simple payback times instead of the more appropriate internal rate of return (that is, a payback time of, say, two years is about equivalent to a 50% rate of return - not bad by any standards).

Often, as the report points out, the idea of switching to more energy efficient systems only crops up when a component, such as a motor, needs replacing. But getting back on line can be of more concern than energy considerations, and repairing the motor often seems the fastest and cheapest option, so the opportunity is missed.

There is nothing new about split budgets, of course. Maintenance departments might actually be the ones investing in new system components, but any savings accruing due to better energy efficiency operation find their way on to another part of the corporate balance sheet. Energy costs are also seldom apportioned to individual production areas - another case, says the report, where little incentive is generated to reduce costs.

Marginally less important, though still significant barriers include the fact that not all parties in the supply chain are sufficiently motivated. In other words, one end of the chain looks only at upfront costs, while down at the user end the focus is more on lifetime costs. There is also a problem in actually defining motor system efficiency correctly, while the perennial problem of oversizing persists. As the report comments, 'installing a high efficiency system is pointless if it is oversized for the job - yet it often happens.'

The ECI's report is part of the Motor Challenge Programme, a voluntary EC initiative to improve energy efficiency.