Using accurate and reliable electricity meters that produce high-quality, verifiable data is essential under the Large-scale Renewable Energy Target.
Metering requirements
Before accrediting your power station, you must show how your electricity meters meet large-scale generation certificate (LGC) eligibility.
We adopt a practical, risk-based approach to metering requirements when measuring electricity generation. This is used in the general formula when calculating certificate entitlements.
The National Electricity Market standards and our metering requirements are dependent on certain factors. These include:
- point of measurement
- volumes of electricity flow
- power station configuration
- operating characteristics.
Electricity meters must be installed at the point that electricity is:
- dispatched from the power station
- delivered as useful electricity to an external load.
Our requirements apply at the point of settlement for Market Registered Generators to measure electricity production and auxiliary loss. The requirements also apply to sub-meters used for calculating LGC entitlements for embedded generators such as rooftop solar.
Measuring distributed or transmitted electricity (DLEG)
To be eligible for accreditation, power stations in the National Electricity Market (NEM) must use NEM standard metering set out in the National Electricity Rules (NER) for their connection point meter. Power stations outside the NEM must use metering that:
- allows us to determine the amount of electricity generated
- meets relevant jurisdictional standards
- is located at the point determined by relevant state or territory authorities.
These meters support the measurement of sent-out electricity (or DLEG).
While DLEG is not generally reported to us, data from these meters can be acquired through our data-sharing arrangement with the Australian Energy Market Operator. This is to test whether power stations are correctly calculating their electricity generation and related LGC entitlements.
Measuring electricity production (TLEG)
When measuring electricity production (TLEG), you're expected to use metering installations for all generator terminals.
Power stations using connection point meters to measure electricity production and auxiliary loss must use meters fully compliant with all aspects of the NER.
For sub-metered power stations, you must meet the relevant NER standards listed below for the amount of electricity that is being measured by the meter.
Relevant NER standards for sub-metering installations:
- have either a visible or an equivalently accessible display of the cumulative total energy measured by that meter
- be accurate in accordance with the requirements in Schedule 7.4 of Chapter 7 of the rules, in particular Table S7.4.3 (accuracy requirements for metering installations)
- be secure and that associated links, circuits and information storage and processing systems are protected by appropriate security mechanisms
- meet relevant Australian Standards and international standards identified in the rules
- have electronic data transfer facilities to enable transmission of energy data to a third party
- include a communications interface to enable the remote acquisition of energy data
- record energy data in a manner that collates the amount of active energy and reactive energy (where relevant), in intervals equal to at least every 30 minutes
- be capable of separately recording energy data for energy flows in each direction where bi-directional active energy flows occur or could occur
- has a measurement element for active energy and if required, reactive energy, with both measurements to be recorded
- include facilities for storing interval energy data for a period of at least 35 days.
If your proposed meter differs from these requirements, you must make a case in your accreditation application. If your sub-meter differs from these requirements, you must show how your proposed meter:
- accurately determines the amount of generated electricity
- produces measurements of a level of accuracy and quality that allows us to determine the eligibility of LGCs created based on those measurements.
Power stations measuring electricity flows of greater than 750 MWh per year should use revenue-grade, pattern-approved metering at these sub-metering points. These have the capability required to accurately measure the volumes of electricity production associated with these power stations.
We may request nominated persons to demonstrate that metering installations are compliant with these standards through our audit framework or through requests for meter testing.
Relevant legislation: Chapter 7 and Schedule 7.4 of the NER.
Calculating auxiliary loss (AUX)
Power stations must demonstrate how the amount of auxiliary loss and imported electricity (AUX) is accounted for in the general formula.
Auxiliary loss is electricity used in generating electricity and operating and maintaining the power station. This does not include any electricity used for network control ancillary services. Imported electricity is electricity imported from an external electricity network.
A meter meeting the sub-metering requirements is considered the most accurate method of measuring the amount of auxiliary loss.
We may accept alternative methods to calculate the auxiliary loss in circumstances where metering is not appropriate or would result in inaccurate measurement.
In these cases, the power station must demonstrate how the alternative method provides an equivalent auxiliary electricity amount. When deciding, we must consider the:
- configuration of the power station
- volumes of electricity flow
- fuel source.
Measuring ineligible energy sources (FSL)
If your power station is using an ineligible fuel source, you should use meters meeting the same requirements for electricity production (TLEG).
If you're using ineligible fuel sources and it can't be metered separately, calculate FSL by converting the energy content of these energy sources into the equivalent number of MWh of electricity.
Temporary variations
We may accept temporary variations to the method of calculating electricity generation where data from meters is not available. This could be from unforeseen issues such as meter failures or disruptions to data access.
In these cases, metering systems not meeting these standards (such as data from inverters in solar photovoltaic systems) may be used by established systems to support LGC eligibility.
You can apply to vary an LGC method by emailing ret-lgcvalidation@cer.gov.au.
The variation may include any reductions in accuracy in measurement from these devices. The use of such devices is only permitted on a temporary basis. You must try to fix the metering issues within 3 months.