What are NGER Methods 1, 2, 3 and 4?

The NGER Measurement Determination sets a hierarchy of estimation methods. Method 1 applies default emission factors. Methods 2 and 3 use facility-specific factors from sampling and analysis, with Method 3 requiring documentary standards for both. Method 4 directly monitors emissions. Higher methods need more data and records but can be more accurate.

NGER Methods 1, 2, 3 And 4 Explained

The NGER methods are a hierarchy set out in the NGER Measurement Determination for estimating emissions from most sources, so that each reporter can match the method to the data it has. Not every method is available for every source.

Key points

Method 1 uses default factors from the Measurement Determination
Methods 2 and 3 use facility-specific factors from sampling and analysis
Method 3 requires documentary standards for sampling as well as analysis
Method 4 directly monitors emissions
Higher methods require additional records and attract regulator scrutiny

Method 1: default factors

Method 1 uses the default emission factors in the Determination, which are based on those used in Australia’s National Greenhouse Gas Inventory. Emissions are typically estimated from activity data, such as fuel consumption evidenced by invoices, multiplied by the default factor. It is the simplest method.

Method 2: facility-specific factors with industry sampling

Method 2 derives facility-specific factors from additional measurements, such as the properties of the fuels actually consumed at the facility. It uses industry sampling practices, with Australian or international standards for analysis.

Method 3: standards for sampling and analysis

Method 3 is similar to Method 2, but both the sampling and the analysis of fuels and raw materials must follow Australian or equivalent documentary standards.

Method 4: direct monitoring

Method 4 measures emissions directly, through continuous or periodic monitoring of emission systems, rather than inferring them from the properties of inputs. It can be more accurate for some processes but is generally more data intensive.

What higher methods require

Facility-specific factors bring extra record-keeping. The Clean Energy Regulator expects records of the monitoring methods used, the results of developing the factors, and details such as biomass fractions and oxidation or conversion factors.

Where method choice is scrutinised

The Regulator publishes the methods used by designated large facilities to estimate fugitive methane from coal mining, oil and natural gas activities. It has also run a thematic audit on the use of higher methods for open cut coal mining. Because the Determination is amended every year, the methods available for each source should be checked against the version in force for that reporting year.

References & sources

Primary regulatory documents and authoritative references underpinning this answer.