Why energy is the real currency of cost engineering

Most cost models in industrial RFQs treat energy as a line item somewhere near the bottom of the spreadsheet — right above "miscellaneous". That placement reveals more about how we model the world than about the actual structure of cost.

Behind every product, every shipment, every welded body-in-white, every pressed sheet, every kilometer of cable, there is energy. Energy is the one input that cannot be substituted. You can change suppliers, you can re-shore, you can swap PLC vendors. You cannot run a factory without joules.

The hidden energy cost of every quote

When we benchmark an RFQ for a new production line, the obvious costs are equipment, software hours, commissioning. The less-obvious cost — and often the deciding one over a 10-year horizon — is the operating energy footprint of the line.

A robotic body-shop cell that draws 30 kW continuous, runs three shifts, and sits in a region paying 0.20 €/kWh, costs roughly €130k/year just to keep moving. Multiply by the number of cells, then by the years to depreciation, and you have a number that often exceeds the original capex of the cell itself.

You don't optimize what you don't measure. Energy is rarely measured at the level where decisions are made.

EROEI applies to factories too

EROEI — Energy Return on Energy Invested — is usually discussed in the context of oil fields and PV farms. The same logic applies inside a factory: how much energy do you have to put in to produce one unit of output? And, more importantly, what's the marginal energy cost of each additional unit?

Lines designed for peak throughput often have appalling marginal energy curves. Lines designed for energy efficiency at expected load look slow on paper but win on operating cost over time.

What this means for cost engineering

Bringing energy into the cost calculation is not a sustainability gesture. It's a profitability lever. Three concrete moves:

First, model expected operating energy at the cell level, not the plant level. Second, treat energy price scenarios the same way you treat FX scenarios — with sensitivity ranges, not point estimates. Third, include PV self-supply potential in the capex case for any new industrial facility. Modern PV often pays back inside the depreciation window of the line it powers.

Energy is not the bottom of the spreadsheet. It's the spreadsheet.

← Back to all posts