EnB (energy baseline) is a quantitative reference value derived from a selected period and used as the basis for comparing energy performance before and after measures are implemented.
How the baseline is determined
A period that reflects normal operation is selected (typically whole calendar years), and consumption is related to the variables that explain it: production output, outdoor temperature (heating and cooling degree days), number of shifts. A simple regression model is often used for this. It allows you to say how much the plant would consume under today's conditions if nothing had changed.
The difference between this “expected” consumption and actual consumption is the saving. The procedure is described in ISO 50006; verification of savings follows M&V.
When the baseline is adjusted
ISO 50001:2018 provides for adjusting the EnB when the indicators (EnPI) no longer reflect actual energy use, or when processes, operating patterns or energy systems change significantly. For example, after a major change in the production programme or after a new hall is added.
Such “changes in static factors” should be recorded and decided on deliberately, otherwise the savings are distorted. The Energy Infra Scan platform therefore flags them for approval.
Example from manufacturing
The previous calendar year is chosen as the baseline year. A model is built from daily data that explains consumption by production output and temperature. If this year the plant consumes five per cent less than the model predicts, at the same output and similar weather, it is a demonstrable saving (illustrative figure) rather than a quirk of the weather.
Frequently asked questions
Is the baseline the same as last year's consumption?
Not always. Last year's consumption is only one possible choice. A baseline normalised for production and weather is better, because otherwise the comparison is also affected by last year having been warmer or by higher production.
Can the baseline change?
Yes, but only for justified reasons, for example a major change in processes or energy systems, and the change is recorded. Adjusting it “to make the savings work out” is a mistake.