Executive summary
1.7 yrs
average payback across nine DOE-verified metered energy programmes
$503K
average annual savings across the same group, mostly from operational fixes
Key conclusions
- Most plants know what electricity cost them last month, but very few know which line, machine or shift drove that cost.
- Eight of the nine DOE-verified facilities achieved most of their savings through operational improvements.
- Submetering shows which automation project is worth doing. It is usually cheaper and faster to deploy than the project it ends up justifying.
Most plants know what their electricity cost last month. Very few know which line, machine or shift drove that cost. Without that information, an energy efficiency programme can only guess where to spend, and a decarbonisation target is only an estimate.
The US Department of Energy's Superior Energy Performance (SEP) programme requires third-party verification of energy performance under an ISO 50001 management system. It measured what closing that gap is worth. Across nine verified facilities, the average payback period was 1.7 years, and eight of the nine took most of their savings from operational improvements. Average energy cost savings across the group were $503,000 a year. No-cost and low-cost operational measures alone saved between $87,000 and $984,000 a year. None of these savings is visible without submetering, because the utility bill does not break consumption down by line or machine.
A single utility bill hides four kinds of waste
- A compressor or chiller cycling overnight with no load, because nobody is watching it at 3am.
- One line or machine carrying a disproportionate share of the site's energy cost, hidden inside a site-wide total.
- A set point drifting slowly out of tolerance, with no single reading extreme enough to trigger an alarm.
- The gap between the equipment's rated efficiency and its actual efficiency once it is installed, loaded and aged.
Three sources make the case for submetering
Have these three findings to hand before you scope a metering project:
| Source | Finding |
|---|---|
| DOE Superior Energy Performance programme (Lawrence Berkeley National Laboratory verification study) | 1.7-year average payback across nine verified facilities; average annual savings $503,000, mostly from operational fixes |
| Singapore Energy Efficiency Grant (Enterprise Singapore, NEA, BCA, MPA, IMDA) | Up to 70% of qualifying cost for SMEs, Base Tier capped at S$30,000, Advanced Tier up to S$350,000 for projects with measurable carbon savings |
| SMARTEE IIoT submetering study, pharmaceutical manufacturing (published in Discover Internet of Things, Springer Nature) | Continuous submetering across chillers, boilers and HVAC, replacing periodic manual readings with real-time per-asset data |
Submetering should come first in the project sequence
Submetering shows which automation project is worth doing, and it is usually cheaper and faster to deploy than the project it ends up justifying. That is why it belongs first in the sequence, ahead of the capital proposal it will later support.
It also answers a second question that most sites now face separately: what their actual Scope 1 and 2 energy figures are, measured at each asset. The per-asset data that reveals wasted overnight cycling is also the auditable input a greenhouse gas inventory needs. One measurement serves both purposes.
