Carbon Capture and Storage

Natural gas (mainly methane) can be seen as a transition fuel. When burnt to produce heat or generate electricity it releases approximately half as much carbon dioxide (450-500g CO2/kwh) as coal (900-950g CO2/kwh). [1] This range can vary depending on the efficiency of the power stations and the type of coal. Collie coal is sub bituminous and generates more CO2 than other black coals, but less than brown coals.

According to the International Energy Agency (IEA) Blue Map, Carbon Capture and Storage (CCS) is expected to contribute nearly 20 percent of the reduction in greenhouse gas emissions required in Australia by 2050. This will come from capturing CO2 from large stationary sources. [2 & 3]

CCS is the only option that allows the world’s existing investment in the fossil fuel infrastructure to be used whilst at the same time bringing about a major reduction in CO2 emissions.

Two CCS projects are currently at different stages of development in WA.

Barrow Island and the Lesueur in Western Australia

The first and most advanced is a proposal to capture the carbon dioxide which occurs naturally in the Greater Gorgon Area natural gas fields and must be removed as part of the gas processing operations. This is known as the Gorgon Carbon Dioxide Injection Project and is an integral component of the much larger Gorgon Project to recover and export natural gas from the northwest shelf. The joint venture operator Chevron2 is in the process of developing the Gorgon and Jansz fields to supply a 15.4 million tonne/annum liquefied natural gas (LNG) plant on Barrow Island, condensate and a domestic supply pipeline with a capacity of 300 Terajoules/day to the mainland.

Barrow Island

In most existing gas processing plants carbon dioxide is vented to the atmosphere, but Chevron propose to inject this into strata over 2 km below the surface of Barrow Island. This is estimated to reduce CO2 emissions from the Project by approximately 40 percent.

The other project is a proposal by a consortium of electrical power generators and industrial users of coal (Collie-South West CO2 Geosequestration Hub) to store carbon dioxide from emitters in Collie and Kwinana. Participants include two coal miners, two alumina refineries, two power generators and a coal to urea project at Collie.

The four year research and evaluation project proposes that CO2 will be transported by a common user pipeline to an injection site within the Shire of Harvey where it will be injected into deep Lesueur sandstone strata.

The major industrial areas of WA lie between Kwinana and Collie. They generate about 25 million tonnes of CO2 per annum. Of this somewhat more than 25 percent is available for capture. This amount should increase as older generating plants are replaced in the next decade. A unique feature of this project is the sequestration of 300,000 tonnes per annum of CO2 in bauxite residue at Pinjarra and Wagerup, where the CO2 chemically combines with the residue and reduces the Ph and provides a more easily handleable material with potential by-product use.

South West Hub

Both proposals are driven by industry. The Chevron-led Gorgon Project is furthest developed having received its final approvals in September 2009. The project is well into a five year construction program with first gas scheduled for 2014. The Australian Government has committed $60 million towards the cost of the carbon dioxide injection project as part of the Low Emissions Technology Demonstration Fund. The State Government commitment has been through the Department of Mines and Petroleum towards independent reviews and technical analysis of the Gorgon carbon dioxide injection project.

The proposed Federal and State government commitment to the South West Hub CCS project is $350m with the bulk of this funding coming from the Australian Government through the CCS Flagships Program and the Department of Mines and Petroleum playing a significant facilitating role for the early part of the project.

 

2The Gorgon Joint Venture consists of Chevron as operator and 47% owner, Exxon Mobil 25%, Shell 25%, Osaka gas 1.25% and Osaka Electrical Power 0.417%.

Stirling Cottage in Harvey