Are you leaving money on the table?

Picture the scene. An engineering team at a processing facility decides it is time to modernise. They identify a motor running below current efficiency standards, procure a shiny new IE4-rated replacement, install it correctly, and duly record a compliance win. Job done. Or is it?

According to industry experts consulted as part of a government-backed review of the UK’s Ecodesign Regulations for electric motors and variable speed drives (VSDs), that scenario plays out on sites across the country — and it routinely leaves the biggest energy savings untouched. The motor gets upgraded, but the system it sits in does not.

The message from those closest to the technology is clear, and it is one equipment owners would do well to hear: focusing narrowly on motor efficiency ratings is, at best, an incomplete strategy. At worst, it can be an expensive distraction.

THE BLINKERED UPGRADE

The efficiency classification system for motors — running from IE1 through to IE5 — has undeniably driven improvements in the products entering the UK market. Regulations have successfully phased out the least efficient motors, and the difference between, say, an IE2 and IE3 motor represents a meaningful reduction in running costs for many applications.

But specialists in the field are increasingly vocal that chasing the next efficiency class on the motor nameplate can lead operators to miss the larger picture. As one application engineer put it during the review process. As Johnathan McNamee from Hayley 24/7 explained: “the whole concept of going from IE2 to IE3, or three to four, can be a little bit blinkered. Sometimes people don’t look at the whole system enough.”

The point is not that motor efficiency standards are irrelevant because they are not. It is that the motor is just one component in a wider mechanical system, and often not the one with the most room for improvement. The gains from a motor upgrade can be dwarfed by a number of issues, such as an inefficient gearbox, a poorly aligned drivetrain, a chain drive running at the wrong tension, or a pump that has been manually throttled to restrict flow.

Fraser Lynch of Westin Drives made exactly that point: “We went out, fitted an inverter and an energy-efficient motor — then noticed the pump was manually valved off to restrict flow. Just opening that valve saved far more than anything we’d just done.”

That quote recounting a job at a quarry captures the problem neatly. A pump had been running against a partially closed manual valve, which was essentially throttling the flow and wasting energy continuously. Opening the valve after installing a VSD cost nothing and delivered savings that eclipsed the entire investment made in new equipment.

It is a dramatic example, but the underlying lesson is widely applicable. System efficiency, which considers the performance of the motor, the driven equipment, and the entire transmission path together, is what actually determines your energy bill. Nameplate efficiency is a starting point, not a destination.

THE BUDGET DISCONNECT

There is a structural reason why sub-optimal decisions keep being made, and it has little to do with technical ignorance. It comes down to how budgets are allocated.

In many organisations, engineering departments are responsible for procurement and maintenance, but energy costs sit in a completely separate budget, often managed by facilities or finance. The engineer tasked with replacing a failed motor is measured on capital expenditure, not on kilowatt-hours saved. Their incentive, therefore, is simply to source a compliant replacement at the lowest purchase price.

Andy Patten of ADC Electricals pointed this out during the government review: “Engineering departments don’t really have that much interest in what the efficiency ratings are or the energy savings, because ultimately that doesn’t come out of their budget. Their focus is simply on what their budget is and how much the unit costs.”

The consequence is predictable. The most energy-efficient option is rarely selected at the point of purchase, because the person making the decision will never see the return. It is one of the most persistent and underappreciated barriers to energy efficiency improvement in industrial settings.

The fix requires organisational change as much as technical change. Equipment owners and asset managers who can align procurement decisions with whole-life energy costs, whether through internal charge-back mechanisms, life-cycle cost analysis tools, or simply ensuring that energy managers have a seat at the procurement table, tend to make consistently better investments.

WHERE THE REAL GAINS ARE

Experts involved in the review were consistent on another point: for most motors currently in service, the incremental gains from moving up another efficiency class are becoming marginal. The easy wins from motor design have largely been captured. As Andy put it, the industry has: “reached the peak where it’s a lot of money to spend to save a fraction of a percent.”

The better opportunities now lie elsewhere. There are three areas in particular worth examining on any site:

• Variable speed drives. Adding a VSD to an application that currently runs at fixed speed can deliver substantial savings, often with a rapid return on investment. Pumps and fans running at full speed but with throttled output are prime candidates. Slowing the motor to match actual demand rather than restricting its output mechanically can significantly reduce energy consumption — and, in some whole-system evaluations, payback periods can be measured in months.

• Right-sizing. One of the most common sources of energy waste identified by field engineers is oversized motors. A motor running well below its rated load operates inefficiently. If a motor has been oversized as a precaution, there may be an opportunity to replace it with a correctly sized unit and realise immediate ongoing savings.

• The wider drivetrain. Gearboxes, couplings, belts, and bearings all introduce losses. Unlike motors, these components have seen far less regulatory attention and technological improvement over the decades. A thorough system audit may well reveal that the gearbox or pump is a greater source of inefficiency than the motor driving it.

MEASURE PROPERLY BEFORE YOU ACT

Any assessment of system efficiency is only as good as the data behind it. This is another area where shortcuts are common and costly. Taking a brief energy reading during a single operating cycle and declaring the system efficient or inefficient is unreliable. Systems often run under varying loads, with different products, at different temperatures and speeds throughout the working week.

Extended monitoring that captures performance data across representative operating cycles, ideally over several weeks, provides a much more accurate picture of where energy is actually consumed and where improvements will have the greatest impact. Condition monitoring technology has advanced significantly and is increasingly accessible for industrial operators of all sizes.

A PRACTICAL FRAMEWORK FOR EQUIPMENT OWNERS

The takeaway for equipment owners is not to ignore motor efficiency standards as compliance remains a legal requirement, and the regulations have been broadly effective in raising the baseline. The takeaway is to treat motor replacement as an opportunity for a broader conversation.

When a motor comes up for replacement, whether through end of life, failure, or planned refurbishment, ask the following questions before simply ordering a like-for-like replacement:

• Is this motor the right size for the actual load it drives, or has it been oversized?
• Is the driven equipment (pump, fan, compressor, conveyor) operating at the efficiency for which it was designed?
• Is there a VSD already installed, or could one be justified on energy-saving grounds alone?
• When were the gearbox, coupling, and transmission components last assessed?
• Who in the organisation is looking at the lifetime energy cost of this asset, not just the purchase price?
• Has enough operating data been captured to understand how this system actually performs under real-world conditions?

These questions cost nothing to ask. The answers could be worth considerably more than the most efficient motor on the market.

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This article appeared in Renew magazine. To read more or request your personal digital or print edition of Renew, click here.