A route to enhanced energy efficiency with energy audits
Erich Labuda, President of Motion Services at ABB, explains how maintenance professionals can improve energy efficiency based on data collected from energy audits.
Erich Labuda, President of Motion Services at ABB.
If there is one thing that truly powers industry, it is motors. They are everywhere, for example, helping pump clean water and power heating, running ventilation, and air conditioning (HVAC) systems etc. There are more than 300 million industrial electric motors in operation currently around the world and, according to the International Energy Agency (IEA), they consume nearly half of all globally produced electricity.
Increasingly, as we move away from fossil fuels, green energy will be used to power these motors. However, it will take a lot of time and money to fully develop the infrastructure required for this transition to renewables.
With the 1.5°C global warming target approaching, a more immediate solution is to reduce energy consumption by making motors more efficient – which also cuts energy costs. This falls in line with the IEA’s prediction that if we are to meet Net Zero by 2050, a third of all emissions reductions need to come from energy efficiency. The IEA has also said that replacing all motors and drives with high-efficiency upgrades would reduce global electricity consumption by at least 10 percent.
Energy audits hold the key to energy efficiency
Businesses are keen to improve their energy efficiency, but they often don’t know where to start. An ABB survey found that, while 97 percent of industry leaders actively want to invest in making their operations more energy efficient, only 41 percent know how to go about it.
Businesses are keen to improve their energy efficiency, but they often don’t know where to start
That is why energy audits are so useful. They tell precisely where the biggest efficiencies can be found across hundreds of motor systems in a plant or facility. This helps maintenance teams make better decisions on how to save energy and cut costs, by targeting motors with the greatest energy-saving potential.
Data can be gathered in various ways: manually, with an expert visiting a site, or digitally with data gathered remotely for regular energy-use updates. With this operational data, an expert can analyse the motor system’s current performance against its potential performance if it were upgraded or resized, for example. The energy savings and emissions avoidance that might be achieved can then be calculated, as well as the projected return on investment (ROI).
The audit itself can be carried out without any impact on a facility’s operations. A plan can be developed to roll-out efficiency improvements in the least disruptive way while maximizing ROI. For example, upgrades can be done in line with routine maintenance schedules to minimize downtime.
Audits in action
A typical way to improve the energy efficiency of the system might include adding a variable speed drive (VSD) to a motor. VSDs enable operators to adjust the speed or torque of a motor in line with the demands of the task. By doing so, they cut energy consumption and bills – reducing a motor’s speed by just 20 percent reduces energy use by 50 percent. Surprisingly, at least half of all industrial electric motors would benefit from VSDs, but only a quarter use them.
Another way to boost energy efficiency is by upgrading to more efficient motors. Many motors in action today rely on outdated IE1 or IE2 technology (where an increasing IE rating indicates greater efficiency). However, modern motors can reach IE5 levels of efficiency, which offer 40% lower energy losses compared to IE3 motors, leading to lower energy consumption and less CO₂ emissions.
Another common finding of energy audits is that many motors are oversized and that resizing them will optimize energy efficiency without impacting reliability. Take an HVAC motor as an example. They are often specified to operate at a maximum load way above the average. For example, they might be engineered to deal with 40°C external temperatures, but that might only occur a few days a year. In addition, system specifiers tend to add a “safety margin” at each stage, which isn’t always necessary and decreases energy efficiency.
That is why it is important to not just evaluate motor efficiency, but the system as a whole. Using the HVAC example, this would also include the fans, condensers and cooling towers. This holistic approach improves overall energy efficiency.
Surprisingly, at least half of all industrial electric motors would benefit from VSDs, but only a quarter use them.
For an example of what an energy audit can do, take the Swedish flooring manufacturer, Tarkett. When the company had an energy audit in 2022, it found that upgrading 10 of its motors to more efficient synchronous reluctance technology (SynRM) with VSDs would boost efficiency from 80 to 95 percent. With these changes in place, it was forecast that Tarkett could save around 800 megawatt-hours (MWh) per year, or the equivalent of charging every German’s smartphone – all 68 million of them. The expected payback period for making these upgrades was just 18 months or less, according to the energy prices at the time.
Identifying efficiencies around the world
To show the true power of energy audits in identifying energy savings, we recently audited more than 2,000 industrial motors across a wide range of sectors and applications. We found potential energy savings of 31 percent per motor if they were upgraded to more efficient technology. The highest savings typically came from motors operating without a VSD. If the suggested upgrades from each audit were implemented, a return on investment (ROI) in as little as three months could be achieved, depending on the local cost of energy.
The audits identified a total of 2.1 terawatt-hours (TWh) of savings over the 20-year lifespan of the 2,000 motors. In other words, enough energy to power 1.25 million houses – the size of a large city – for a full year.
The audits were conducted across a variety of countries. However, if we imagine that all motors were operating in the UAE, based on November 2023 data, a 2.1 TWh energy saving would avoid 1.5 million tonnes of CO2 emissions and have an ROI of six months. Equally, if they were in Germany, savings would amount to 940,000 tonnes of CO2 and an ROI of just three months. These savings would be enough to offset the emissions of a coal plant for three months in the UAE and two months in Germany.
By scaling up these results to cover the 300 million industrial motors operating worldwide, you can start to imagine the potential impact of upgrading inefficient motors all over the planet.
The solution is clear, then. It is time we increase energy efficiency to cut costs and emissions. Energy audits streamline the process by highlighting the best places to make those efficiency improvements, representing a straightforward way to meet Net Zero targets.
Text: Erich Labuda Images: ABB
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