Natural gas quality varies between reservoirs and is defined by the proportion of its components, such as methane, ethane, and inert gases. Gas quality is important because pipelines, storage facilities, industrial equipment and gas appliances are designed to operate safely and efficiently within particular gas quality limits. Historically, those limits have been managed through commercial contracts between gas producers, pipeline operators, storage facility operators, retailers and large consumers.
The Gas Supply (Gas Quality Specifications) Act 2009 (the Act) and Gas Supply (Gas Quality Specifications) Regulations 2010 (the Regulations) allow broader specification gas to enter the market without requiring every affected contract to be individually renegotiated. It does this by creating two main gas quality specifications for transmission pipelines that set the permissible limits of the natural gas components. This ensures the gas is suitable for transport, use, and combustion. Broadening the gas specification means changing the outer limit of some of the components, while still meeting safety standards.
Standard specification
The standard specification represents the broadest gas quality that may ultimately be supplied to consumers under the scheme. It acts as both a minimum benchmark for gas quality and a long-term signal to industry regarding the direction of gas quality standards in Western Australia.
The standard specification is intended to support the safe operation of gas systems while allowing greater flexibility in the composition of gas supplied to the market.
Reference specifications
A reference specification is prescribed for each transmission pipeline. It broadly reflects the gas quality specification that applied to the pipeline on 1 January 2009 and serves as the baseline against which impacts from broader specification gas are assessed.
Reference specifications are central to the operation of the framework because they determine:
- whether a Pipeline Impact Agreement (PIA) is required before gas below the pipeline’s reference specification can enter a pipeline; and
- whether gas producers must compensate pipelines, storage facilities or large gas users for impacts caused by gas supplied below the relevant baseline specification.
The Regulations prescribe the detailed specifications and other operational requirements needed to implement the scheme.
Further information is provided below about aspects of the gas quality framework, including PIAs and exemptions.
