Energy Reuse Effectiveness (ERE) Calculator
Calculate Energy Reuse Effectiveness by subtracting recovered heat or power from total facility energy before dividing by IT energy consumption.
Planning aid for sustainability analytics; confirm definitions against The Green Grid's ERE reporting guidance before regulatory filings.
Examples
- Facility 1,250,000 kWh, IT 820,000 kWh, reuse 210,000 kWh ⇒ 1.27 ERE (net facility energy 1,040,000 kWh)
- Facility 980,000 kWh, IT 640,000 kWh, reuse 0 kWh, factor 0.5 ⇒ 1.53 ERE (net facility energy 1,960,000 kWh)
FAQ
What does the normalisation factor represent?
Use the normalisation factor to scale partial-period readings to an annual basis or to align metered subsets with whole-facility reporting boundaries.
Can Energy Reuse Effectiveness be less than 1?
Yes. When a facility reuses enough waste heat so that net facility energy approaches IT energy, the ratio trends toward 1. Values below 1 indicate more energy was reused than consumed outside the IT load, which usually signals metering errors.
How should I treat renewable electricity exports?
Only include recovered energy that is directly attributable to waste heat or captured load from the data center. Renewable generation dedicated to the site does not count toward reuse in the ERE formula.
What level of precision should I report?
Round the ERE ratio to two decimal places and keep the intermediate energy values with at least whole kilowatt-hour precision for auditability.
Additional Information
- ERE is dimensionless; values are typically reported with two decimal places.
- Normalisation factor defaults to 1.0 when left blank so short study periods can be scaled without errors.
- Ensure all energy readings originate from the same reporting window and metering scope.
- Recovered energy should be measured in delivered kilowatt-hours or via validated heat-to-energy conversions.