Advanced Energy Audit
01The problem
One tool, one answer
A tool sizes one fix at a time: a VSD on a fan, the right notified maximum demand, a capacitor bank. Each answer is right for the question it was asked, and each assumes nothing else on site changes.
Demo Foods, fictionalAsked on its own, a trim compressor saves 59 MWh a year.
The whole plant
Repair the compressed-air leaks and a variable-speed trim compressor has less left to trim. Tune a boiler and its economiser recovers less heat. Added up tool by tool, a plant's savings come out too high. The audit applies interacting measures in order, each on what the one before left, and shows the overlap it removed.
Demo Foods, fictionalIn sequence, after the leak repair, the same compressor saves 12 MWh.
02The journey
Where does the energy go, and how sure are we?
Which measures, and how much each one really saves?
What do we do first, and is it worth the money?
03What you get
Volume 1 · Management summary
For the managing director and the finance team
Volume 2 · Engineering report
For engineers and reviewers
The Excel model
For the investment committee
Financial lens
For a credit committee, the debt the savings can carry, sized to a debt-service cover ratio.
04Why it can be trusted
Each figure carries a tag and a ± band. Bands combine through the calculations, and a result is never rated better than its weakest input, so you know which estimate to firm up first.
Default bands, used only where a figure has no stated uncertainty of its own.
The audit process and balance follow ISO 50002-1, the baselines and energy performance indicators ISO 50006, the baseline statistics ASHRAE Guideline 14, and the measurement and verification plans IPMVP and SANS 50010, the standard behind the section 12L allowance.
The bottom-up estimate for every carrier is tested against what was metered and billed. Whatever the estimates do not explain stays on the diagram as unaccounted, so you can see how far the picture can be trusted.
Every formula, conversion factor and default names its public source. Costs come from a cost library marked as placeholders until a supplier's quote replaces them, and the report says which measures still rest on placeholders.
The Excel workbook holds the audit as live formulas: bills, register, balance, every measure, cash flows and the portfolio. An investment committee can follow any figure back to its inputs, cell by cell.
Set system by system, never for the whole site at once: bills may be enough for the lighting, while the steam plant gets measured.
Level 1±30% or worse
12 to 24 months of bills for every carrier, and a walk-through
Each carrier's metered total, shared across end uses from the walk-through
Level 2about ±20%
An equipment register: nameplates, load factors, hours and efficiencies
Bottom-up energy per item, reconciled to the bills
Level 3about ±10-15%
Half-hourly meter data, sub-meters or loggers, and production
Measured energy, load profiles and regression baselines
Level 4about ±5-10%
Mass flows, temperatures, pressures and the plant historian
Energy and mass balance per process unit
05From the free tools
06The example
Screen 1 of 5
The balance drawn to one scale: electricity, LPG and diesel in, end uses and losses out, the unaccounted remainder as its own dashed flow, and hatching where figures are still assumed.
Demo Foods (Pty) Ltd is fictional; every figure on screen is invented. Full size
Demonstration only. Demo Foods' bills, equipment and costs are invented to show the method; capital costs are the cost library's placeholders and three fictional quotes. A real audit replaces them with the site's data and suppliers' prices, and its results will differ.
A line or two about the site is enough to start: what it makes, the energy it buys, and roughly what the bills come to. I reply personally.