ESS baseline

Written and checked by the Energy Merchants desk · Reviewed 3 October 2026

An ESS baseline is the benchmark of what a site or piece of equipment would have used without the upgrade. The NSW Energy Savings Scheme (ESS) rewards the difference between the baseline and what the upgraded equipment actually uses, in the form of Energy Savings Certificates (ESCs). For the scheme, see ESS definition.

Without a baseline there is nothing to subtract from. A new efficient pump uses less energy than it used to, but a certificate only makes sense if the saving is measured against a credible alternative.

How baselines are set

The ESS offers several calculation methods, and the baseline is built differently in each.

• Deemed savings. The scheme sets a fixed baseline for the activity, for example a standard lighting load, and the saving is read from a table. See deemed savings.
• Metered baseline. A site’s own past metered consumption sets the baseline. See metered baseline method.
• Measurement and verification methods. The baseline is modelled or measured, then verified against after-upgrade data. See project impact assessment.

A worked figure

Illustrative only. A factory used 1,000 MWh in the baseline year. After a compressor upgrade, and adjusting for production levels, it is expected to use 920 MWh. The baseline saving is 80 MWh, and ESCs are created in proportion to it under the scheme’s rules. Change the baseline assumption and the certificate count changes with it.

In practice

For installers working with business customers in NSW, the baseline is the first discussion with the accredited certificate provider. Records such as 12 months of bills, interval data and production figures are needed. See accredited certificate provider.

Common confusion

The baseline is not the “before” reading alone. It is the adjusted expectation of what would have happened without the project, so factors like production volumes and weather get normalised.

It is also not a rule that applies to rooftop solar or batteries, which sit under different schemes.

See veecs and stcs on the same job and /resources/. More in the glossary.