2003-03-28 - High efficiency motors have not really caught on in UK industry. The question is why - after all, there is little point in heating your plant with the energy losses from hundreds of motors, when this power could be put to useful work and help save money. Steve Ruddell, general manager for electrical machines at ABB in the UK, explains why there is little incentive for users to opt for high efficiency motors.
Electric motors use 65% of all electricity in industry. If we as a nation are to make any efforts to reduce energy consumption, this might seem a good place to start saving. Unfortunately, there are currently not enough incentives for users to opt for EFF1 high efficiency when specifying motors.
A single 90 kW EFF1 motor can save in the region of £10,000 worth of electricity, over the course of its life, compared to its standard efficiency (EFF2) counterpart. Bearing in mind that UK industry uses some 10 million motors, the savings potential is huge. However, the person specifying the motor is unlikely to be the same person who worries about energy costs, and so motors continue to be specified on the basis of lowest purchase price and hence potentially lowest efficiency.
In an effort to raise motors on the agenda, high efficiency motors have been included on the government’s technology list of energy efficient products, qualifying for enhanced capital allowances, but so far with little effect.
'High efficiency' was a relative term until 1998 and the establishment of EURODEEM, the European database that gives efficiency details of low voltage AC motors over the web (at www.iamest.jrc.it/projects/ eem/eurodeem.htm). To make life easy for users, a labelling scheme was introduced, where low efficiency motors were labelled EFF3; standard energy efficient motors, EFF2; and high efficiency motors, EFF1.
Knowledge is power, was the reasoning, and knowledge of efficiency would empower users to opt for efficiency. Market forces would then phase out the lowest efficiency models. While the latter appears to have happened - very few EFF3 motors are these days offered for sale in the European marketplace - the mass move into EFF1 has still not taken place.
There are a couple of reasons for this. Firstly, it is not too difficult to enhance a motor sufficiently to move it from EFF3 to EFF2. Moving from EFF2 into EFF1 can be more challenging, especially in smaller frame sizes, as more active materials have to be fitted inside the space confines of the frame. Also, the EFF2 band is unacceptably wide. There is little incentive for a manufacturer just over the threshold from EFF3 to make further improvements, if there is no chance of his motor ever becoming an EFF1 model. Just moving slightly higher within EFF2 won’t do him any favours, so he might as well stay at the bottom. Yet, there can be huge differences in efficiency between motors within EFF2, which the avid energy manager might be tempted to give a closer look.
Then came the introduction of the climate change levy in the UK and the subsequent enhanced capital allowances for energy efficient products such as EFF1 motors. These enable the user to deduct the full cost of applicable items against corporation tax in the year of purchase, instead of writing it off over a number of years as a depreciating asset. If the motor is purchased as part of a larger piece of equipment, the buyer can still claim the value of the motor based on the motor size, from the government web site, at www.eca.gov.uk.
Unfortunately, during the negotiations leading up to the introduction of the scheme between the government and the manufacturers, these values were reduced, to a point where the potential financial gain for the user is often outweighed by the price difference between EFF1 and EFF2 and the effort required to claim the allowance. For most users, it is not worth doing if the motor is rated below 30 kW.
The problem from an environmental point of view is that the bulk of motors in use are below 30 kW. It is also in this segment that the greatest improvements in efficiency can be made. While the difference in efficiency is normally in the region of 1-2% for a 75 kW motor, it can be as much as 7% for a 1.1 kW motor. It may not sound much in either case, but due to their sheer numbers and long running hours, motors use large amounts of energy and any improvement in average efficiency would make a great impact. To generate the power for a 30 kW motor over its lifetime, some 12 tonnes of coal, 2 tonnes of natural gas and 2 tonnes of oil will be burnt. And remember, there are 10 million motors out there.
If we are serious about tackling energy use, it is high time users were given a reason to look at high efficiency motors. The technology is available now, only the incentive, and hence the will, is lacking.