Chevron Australia's proposal is to expand the LNG production capacity of the Gorgon gas development foundation project on Barrow Island from 15 million tonnes per annum to 20MMtpa through the fourth train development.

This will involve constructing a feed gas pipeline system along the Northern Pipeline Route Option or the Southern Pipeline Route Option, and the addition of a fourth LNG train and associated infrastructure within the existing gas treatment plant on Barrow Island.

"The EPA considers that the proposal can be managed to meet the EPA's objectives for benthic communities and habitat, and marine environmental quality," the authority said in its 66-page report, although it added the caveat that certain conditions had to be met.

The EPA also said the proposal be could managed to meet the its objective for air quality and atmospheric gases, given certain conditions, and also for marine fauna - all of which were developed in consultation with several government departments including Mines and Petroleum; Environment Regulation; Parks and Wildlife; State Development; Transport; and Aboriginal Affairs, among others.

The expansion plan still needs approval by state and federal environment ministers.

Nine agency submissions and one public submission were received during the public review period for Chevron's fourth train proposal. These, in part, related to impacts on benthic communities and habitat and marine environmental quality from horizontal directional drilling and offshore gas pipeline laying activities.

The submissions also raised concerns over impacts on marine fauna - especially marine turtles - from artificial light, HDD and offshore gas pipeline laying activities, noise and vibration, vessel movements and discharges; and air quality and greenhouse gas emissions.

In assessing Chevron's proposal, the EPA noted that the JV sought to avoid and minimise environmental impacts by:

• ensuring that the clearing of up to 10 hectares of terrestrial vegetation at the HDD site falls within the 332ha limit allowed under the Barrow Island Act 2003
• refining the lighting design of the GTP to reduce light emissions and potential impacts on marine fauna
• minimising emissions of atmospheric pollutants from the GTP by using management measures and pollution control technologies that are commensurate with best practice and best available technology and
• injecting about 80,000t of reservoir carbon dioxide a year generated by the fourth Ttrain expansion proposal into the Dupuy Formation beneath Barrow Island using the foundation project reservoir carbon dioxide injection system infrastructure.

Chevron first referred the proposal to the EPA on April 28 2011, with a Public Environmental Review available for public review from July 7-September 1 last year.

While Australian energy projects developers have been scaling back or deferring plans following the plunge in world energy prices that have lowered returns on those investments, Edison Investment Research said this week that while many were in doubt, Gorgon was safe, along with Japanese major Inpex's Ichthys project.

Chevron's partners in Gorgon are Shell Development (Australia), Mobil Australia Resources Company, Osaka Gas, Tokyo Gas and Chubu Electric Power.