Embarking on an energy-efficiency drive
Building services, with its demand for cooling and space heating, is one of the major users of motors
With today’s overriding concerns about energy efficiency, is the building services sector missing a great opportunity to make their buildings more efficient. With energy efficiency one of the topics on everyone’s minds these days, looking for ways to save energy is a top priority for many people. One of the major uses for electrical energy is in electric motors, and the 10 million or more around the world account for a big proportion of the global energy use. Building services, with its demand for cooling and space heating, is one of the major users of motors, and building service managers are therefore looking for savings as energy costs rise. With so many motors used, ensuring they are the most efficient available is vital. After all, an 11kW motor costing about £500, can consume over £50,000 worth of electricity in 10 years. High-efficiency motors can give significant cost savings if used in the right applications. Compared to a standard motor, a high efficiency model can be up to 3% more efficient. To make life easy for users, a labelling scheme has been introduced, which labels low-efficiency motors EFF3, standard energy efficient motors EFF2 and high-efficiency motors EFF1. A 90 kW high-efficiency EFF1 motor could cost £1200 more to buy than the standard EFF2 model, but will save £12 000 during a 10-year service life. The failure to fit a high efficiency motor may therefore cost the users £10 800 — a fairly hefty cost for what at the time may seem a small decision. The simple payback period is just over a year. Yet, the energy efficiency of motors has not been high on the agenda in the building-services sector. For anyone other than the end user, the issue of energy efficiency tends to be irrelevant, as it is only somebody else’s money that will be spent running the motors for the rest of their operational lives.
Purchase price is not the only factor The cost of more efficient motors is also often cited as a reason for specifying motors with a lower purchase cost. However, cheaper motors are not as cheap as they might seem. As well as reducing energy costs, high-efficiency motors also bring better reliability, reduced downtime and lower maintenance costs, through better tolerance to thermal stresses and an improved ability to handle overload conditions. Energy efficiency is far more significant to the bottom line than the purchase price. Saving a few pounds up front by buying a less-efficient motor could end up costing a lot more in the longer term. In terms of total life-cycle costs, the continuing energy use of a motor is far more important than its initial purchase price. Another reason for investing in higher-efficiency motors is Part L of the latest Building Regulations, with buildings having to be checked to ensure that the calculated carbon-dioxide emissions from energy consumption are no greater than a specific target value for the type of building. Energy-efficient motors are one of the simplest measures to introduce to keep the overall energy consumption of the building to a minimum.
The best applications for energy efficient motors For new applications, buying high-efficiency motors is usually the best option as they can save many times their purchase cost over their average 15 year life span. But what are the right applications for high efficiency motors? When choosing applications to suit high efficiency motors: • Choose applications where motor running time is greater than idle time.
• Review applications that use high-power motors, where the potential for cost savings can be significant.
• Select applications where loads are fairly constant and where the motor operates at full load most of the time.
• Consider energy-efficient motors for areas with high power costs.
Save money and reduce tax Energy-efficient motors qualify for Enhanced Capital Allowances (ECAs), which allow companies to deduct the full cost of the investment against corporation tax in the first year. The list of motors includes the following. • All 2- and 4-pole motors from 1.1 to 90 kW that meet the CEMEP EFF1 efficiency ratings. • All 2- and 4-pole motors from 90 to 400kW and 6- and 8-pole motors from 5.5 to 315 kW that meet the water-industry motor-efficiency standards (WIMES) requirements for 6-pole motors. ECAs increase the value of the tax benefit and improve cash flow; the ECA is equivalent to a rebate of 6 to 15%. For high-use applications like HVAC and other building-services uses, high-efficiency motors are a must. Combined with the tax benefit of the ECA scheme, they are a win-win deal for building managers. Ian Allan is Manager for Low-Voltage Motors with ABB Ltd
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