Last month, Queensland Premier Anna Bligh announced the State Government’s intention to acquire land for a ‘gas superhighway’ leading into the Port of Gladstone to facilitate Queensland’s LNG development.

Some of the planned pipelines are expected to be 26–32 inches in diameter, which is significantly larger in diameter than existing natural gas pipelines.

This will present some challenges for the Australian pipeline industry. Since 1984, the largest pipeline constructed in Australia has been 26 inches in diameter. The technical challenges are not insurmountable; the main issue will be in sourcing appropriately sized equipment to deal with the larger pipe and it is likely that some of the necessary equipment will need to be brought in from overseas – an expense that can have a dramatic impact on a project’s bottom line.

Fortunately, there is a new industry emerging that will be building similar infrastructure, and similarly large pipelines, with the same equipment as the petroleum and coal seam gas (CSG) industries: the carbon capture and storage (CCS) industry.

Government initiatives

The Australian Government is seriously committed to the development and commercialisation of the CCS industry, specifically through its funding of:

* $500 million through the National Clean Coal Initiative over eight years from 2007–08 * $100 million per annum to the Global Carbon Capture and Storage Institute * $500 million through the Low Emissions Technology Demonstration Fund (not all the projects are CCS specific, but most of them are).

The Federal Government has also indicated that some of the revenue raised from the Carbon Pollution Reduction Scheme’s emissions trading scheme will be allocated to technologies that aim to capture emissions from coal-fired power generation, otherwise described as ‘clean coal’. Additionally, the Government provides funding to the Co-operative Research Centre on Greenhouse Gas Technologies (CO2CRC), the Co-operative Research Centre for Coal in Sustainable Development and has a CCS Division at the CSRIO and Geoscience Australia.

The CCS industry will require significant infrastructure investment to achieve the kind of outcomes that the Government is hoping for, which could see upwards of 90 per cent of the stationary energy sector’s total emissions captured by 2050. In 2006–07, the stationary energy sector’s emissions totalled 287.4 million tonnes of carbon dioxide equivalent. With that as a starting point, the CCS industry has the potential to be very large.

Transporting CO2

Considerable effort and attention is focused on the capture and storage technologies required to bring CCS to commercial reality. An often overlooked issue is that of transportation. Clearly, it should be described as CCTS! While the transportation of CO2 by pipeline is not new – there are several thousands of kilometres of carbon dioxide pipelines in the United States; most built over 20 years ago – there are some real challenges that need to be addressed.

The primary commercial driver for existing CO2 pipeline infrastructure has been the use of CO2 in enhanced oil recovery. This, combined with ageing pipeline infrastructure, means CO2 pipelines are over engineered by today’s standards. Today’s gas pipelines are thin walled, engineered to minimise the amount of steel required for construction. Moreover, the physical properties of CO2 are sufficiently different from that of natural gas, so that CO2 pipelines cannot be built with a simple business-as-usual approach. Issues such as the pressure/flow regime, fracturing and corrosion all need to be dealt with separately.

Another factor that is considerably different when transporting CO2 is that it will be transported in its supercritical phase. CO2 enters its supercritical phase at a temperature of 31°Celsius and a pressure of 7.31 mega pascals, which makes it an economically viable option for pipeline transportation because more than 200 times as much capacity is achieved over gaseous CO2. The supercritical temperature is the key; 31°Celsius is manageable in current pipelines, unlike the 183°Celsius temperature necessary to get natural gas into a supercritical phase. So, while this poses challenges for pipeline infrastructure, it does make the transportation more economical.

Transporting any fluid requires energy, and this tends to be a non-issue with natural gas as the gas itself can be used to power compressors. CO2 has no energy value, so power for pressurisation on a pipeline will be a major issue. A typical compressor station (CO2 will use pumps) requires 30 megawatts of power.

There are plenty of challenges, and opportunities ahead. Clearly, gas transportation will continue to be an important part of the nation’s energy infrastructure – whether it is for the large resource of CSG in Queensland and New South Wales, or a new national transmission grid for CO2 emissions.