Most ESC activity is deemed: the rule says a particular upgrade saves a set amount. Some projects do not fit that mould. A factory process change, a large compressed-air overhaul or a data centre cooling upgrade saves energy specific to the site. For these the NSW Energy Savings Scheme offers measurement-based methods, and two of the best known are Project Impact Assessment with Measurement and Verification (PIAM&V) and the metered baseline method (MBM).
PIAM&V
PIAM&V proves the impact of a project by measuring energy use before and after, adjusting for variables like production volume or weather. The steps are broadly:
- Define the project and the boundary. What equipment and energy flows are in scope.
- Measure the baseline. Collect data on energy use before the change, long enough to capture normal variation.
- Implement the project.
- Measure after. Collect data with the same boundary and adjust for differences in conditions.
- Calculate the savings and create ESCs. An independent assessor often reviews the calculation, and certificates are created through an Accredited Certificate Provider.
See the glossary entry on project impact assessment with M&V.
The metered baseline method
The metered baseline method creates ESCs by comparing metered energy use after an upgrade against a baseline built from metered historical data. It suits sites with good metering, such as buildings with sub-meters, where the baseline can be modelled against drivers like weather and occupancy. See the metered baseline definition.
How they differ
| PIAM&V | Metered baseline method | |
|---|---|---|
| Basis | Measured before and after for a defined project | Metered historical baseline compared with later use |
| Best for | One-off projects with a clear boundary | Sites with long metering history |
| Evidence | Detailed M&V plan and reports | Data quality and baseline model |
The exact rules, eligibility and calculation requirements are in the NSW Energy Sustainability Schemes method guides, which change, so treat this as orientation only.
Practical points
- Data quality is everything. Gaps, meter changes or one-off events can undermine a claim.
- Plan before you start. The baseline period usually has to be set before the project begins, and approvals may need to be in place first.
- Budget for assessment. Measurement projects carry consultant and assessor costs, which should be weighed against the ESC value.
- Prices move. ESC prices change: see ESC price.
What this means for installers and businesses
If you work on large sites, ask the ACP early which method fits, and agree who carries the measurement cost. For smaller jobs stick to deemed activities. For context see NSW ESS for installers, how ESCs are traded, pricing and how it works.