Why energy is now central to manufacturing cost control

A car plant can trace a single bolt to the millisecond it was torqued, yet ask the same plant how many kilowatt hours it burned turning that bolt, and the answer often arrives days later, and likely aggregated by an external department rather than tracked on the shop floor.

That gap - between manufacturing's obsession with precision and its apparent indifference to power - is becoming an costly one to ignore. As OEMs and tier suppliers confront margin pressures from every direction, from raw materials to electrification, through to labour, the plants able to treat energy consumption with the same rigour as throughput or quality are starting to pull ahead.

Richard Lawton, Vertical Account Manager at Mitsubishi Electric's Automation Systems Division UK, has spent years watching that gap persist, and argues it can no longer hold. "Energy needs to be part of the true cost of production," he says. "Without understanding how much energy a process is consuming, and what that costs, manufacturers don't have a complete picture of their manufacturing costs."

At Mitsubishi Electric, he adds, "we see energy management increasingly becoming part of the wider conversation around operational efficiency, rather than something that's considered separately."

Data without direction, ships without destinations

The industry's problem is rarely a shortage of data. Most modern plants are awash with it, generated by sensors, PLCs and metering systems scattered across dozens of production lines. The real difficulty, according to Lawton, is that this information tends to stay where it is captured rather than travelling to where the decisions are made. "Manufacturers collect huge amounts of data, but this is often captured locally rather than across the whole plant," he says. "The challenge is then knowing what to do with it."

And that disconnect creates a subtler problem than simple lack of awareness. Energy monitoring can surface high-consumption areas that management never flags as priorities - because visibility and criticality are not the same thing. "Energy monitoring and analytics can identify areas of high consumption, but these aren't necessarily the processes that management considers most critical," Lawton notes. 

"The right tools are needed to put energy data into context and help facilitate practical decision-making." In other words, the value of energy data lies not in its volume but in its translation, from raw consumption figures into decisions a plant manager can act on before the next shift begins.

Investment allocation - where to spend first?

Asked to prioritise, Lawton resists the temptation to lead with headline technology. The starting point, he insists, is the act of measurement itself. "The first step is understanding current consumption, so energy meters and energy surveys should be a priority," he says. "You can't know what you can save until you know what you're using." From there, the targets are familiar to anyone who has walked a vehicle plant floor. "Press and paint, for example, are often two of the largest energy-using processes, so they should serve as prime areas of focus."

Once that baseline exists, the returns tend to compound. Manufacturing execution systems, Lawton argues, are frequently undervalued as energy tools rather than production tools. "Manufacturers shouldn't overlook the effectiveness of implementing manufacturing execution systems, which can help them to identify where stored energy can be used for weekend work, or where machinery can be powered off after operating hours or during shutdowns."

Only after that foundation is in place, he suggests, does hardware investment such as more efficient motors and variable speed drives make full sense, since "technologies such as more efficient motors and variable speed drives can also help target the areas where the greatest savings are possible."

Prove it small, scale it fast

Lawton's caution against leading with technology extends to how that technology is rolled out. His preferred model is incremental, testing an approach in a contained area before committing capital across an entire site. "A useful approach is to start small, establish the return on investment and then scale," he says. "For example, trialling the technology in isolated areas before rolling it out more widely."

Fans and pumps offer a low-risk entry point with outsized returns, particularly around paintshops, HVAC and water systems, where the physics of fluid dynamics rewards modest changes disproportionately. "Installing fans and pumps across paint shops and in HVAC and water systems is a great starting point, with a small reduction in speed having the potential to produce a large reduction in power consumption." Battery energy storage systems follow a similar logic on a larger scale, with the biggest gains concentrated where demand is heaviest.

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"The same principle can apply to battery energy storage systems, with most energy intensive areas, such robot welding, presses CNCs (Computer Numerical Controls), paint shops, HVAC systems and onsite EV charging infrastructure, standing to gain the most from implementation." The discipline, he says, is less about the technology itself than the sequencing around it. "It's key to understand where the technology can deliver value, demonstrate that value and then build the business case for wider deployment."

Electrification raises the stakes

If energy management was once a matter of good housekeeping, electrification is turning it into a competitiveness issue. As more of the manufacturing process itself becomes electrified, power consumption stops being a background cost and starts shaping whether production remains viable in high-cost markets at all.

"As manufacturing becomes more electrified, energy becomes an even more important factor in competitiveness," Lawton says. "If production isn't profitable, it won't stay in the UK." Given the cost pressures already bearing down on OEMs and Tier One suppliers, he frames energy efficiency not as an optional sustainability measure but as a defensive one. "Manufacturers need to treat energy efficiency as part of protecting the long-term viability of their operations."

The practical steps he outlines are unglamorous but effective, from automatically shutting down agreed, non-critical loads at the end of a shift, to storing electricity for use during expensive or high-demand periods. Maintenance discipline matters just as much as new capital equipment.

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"Replacing inefficient motors, maintaining bearings and preventing equipment from operating under unnecessary loads, meanwhile can also prove effective." Tying it together, he says, requires both modern hardware and the software layer to make sense of it. "The key is to upgrade hardware onsite so that it is more efficient and cyber compliant, and to have a Manufacturing Execution System (MES) package in place that enables manufacturers to take a much more holistic approach to monitoring and managing energy usage."

That same discipline underpins resilience against volatile energy markets and supply disruption more broadly. Lawton is candid that the sector's instincts often work against it. "Manufacturers need to become more proactive. Automotive manufacturing can be very reactive, with action often taken when something breaks rather than before a problem occurs."

His prescription is deliberately prosaic, but important. "Preventative maintenance, better energy monitoring and longer-term supply agreements can all help manufacturers reduce uncertainty and respond more effectively to changing costs."

Beyond the hype: a measured view on Artificial Intelligence

Given the current enthusiasm for artificial intelligence across manufacturing, Lawton's assessment of its role in energy optimisation is notably restrained. "It's still too early to say," he says. "AI has a future in energy optimisation, but from our perspective at Mitsubishi Electric, it remains more of a future opportunity than something we can point to as delivering widespread measurable value today."

His advice is to resist the urge to skip ahead. He believes that "manufacturers should focus on getting the fundamentals right first, understanding energy use, improving visibility and acting on the data." An even-handed and rational approach, indeed.

Future-focus: the productions plants that will win

Asked to look five years out, Lawton's picture of the most energy-efficient automotive factories is less about any single breakthrough technology and more about culture. "The most efficient factories will be data-driven and well planned, with energy management built into day-to-day operations rather than treated as an afterthought," he says. "Technology will play an important role, but it needs to be supported by good data and a clear understanding of where energy is being used."

His closing assessment doubles as a warning to plants still treating energy as an afterthought. "Ultimately,” he says, “the most future-proofed plants will be those that can improve efficiency while remaining profitable and competitive."

And since of course, automotive manufacturing is more than accustomed to measuring itself in units-produced-per-hour - this is a clear reminder that the next competitive edge may in fact, be calculated in kilowatts-saved.