34 n ENERGY EFFICIENCY September 2024 www.drivesncontrols.com Should you upgrade your motors to save energy? Motor efficiency has come a long way in a relatively short space of time. Efficiency classes for motors were only standardised internationally in 2008, and at that time the highest defined class was IE3. Since then we’ve seen the introduction of IE4 motors. In 2019, ABB’s SynRM (synchronous reluctance) machine became the first commercially available motor to achieve IE5. More recently, the company has also launched a range of motors meeting the anticipated IE6 efficiency level in magnet-free SynRM designs. Motor manufacturers have a vested interest in selling more motors, and particularly in selling new, high-efficiency machines. The case for upgrading is relatively simple – a motor’s purchase price is around 1% of its Total Cost of Ownership (TCO), while maintenance is a further 2%. The remaining 97% is the cost of running – energy costs. The more efficient a motor is, the lower its energy costs through its lifetime. A typical motor can run for decades, so even a small improvement in efficiency will pay for itself several times over during the course of the motor’s operating life. With energy costs spiralling in recent years, the equation becomes even more compelling, and payback times of a matter of weeks are not unheard of. As well as cutting running costs, improving efficiency is clearly good for the environment too. Against the wider backdrop of the drive towards net-zero, and the urgent need to reduce carbon emissions, it’s undeniably impressive how manufacturers are continuing to push motor efficiencies to the very limit. Indeed, just a few years ago, IE5 was considered purely theoretical. Not only has IE5 been achieved, but manufacturers are now offering and developing even higher levels of efficiency. Offsetting costs On paper, it might seem that upgrading to the highest efficiency motor available is a win-win. The purchase cost can, in theory, be offset through the new motor’s lower lifetime energy costs, while newer synchronous reluctance motors also tend to be more reliable, longer lasting and quieter, as well as offering other benefits. However, in the real world, no one wants to be replacing their motors each time a new one comes on the market. It costs money, takes a lot of effort, and may also require downtime. If a motor has only been in place for a short period of time then, unless you’re jumping several efficiency classes, the potential savings from upgrading might not be that impressive. Furthermore, replacing a motor has an inherent carbon cost. The old motor will need to be disposed of, while a new motor needs to be manufactured, transported to site and installed. The actual carbon impact of this can be difficult to calculate, although this is hopefully set to change in coming years with the increased adoption of Environmental Product Declarations (EPDs). These aim to provide greater transparency of the true carbon profile of a product over its whole life. To gain EPD certification, product manufacturers must provide complete transparency over the origin and carbon impact of all of the materials and processes involved in the manufacture, use and disposal of the device, both at the component level and as a whole. For now, EPDs are not mandatory, however ABB’s SynRM motor is one of an growing number of products which already have third-party verified EPD certification, in accordance with ISO 14025. When considering the future for your motors, you need to consider many factors including efficiencies and payback times. Richard Gee, ABB’s sales manager for LV motors in the UK, explores some of the other aspects that need to be considered in when upgrading motors. The latest synchronous reluctance motors can have IE6 levels of efficiency – even though IE6 is not yet officially defined
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