Storage capacityAustralia has very extensive basins with deep saline formations, both onshore and particularly offshore, in which large quantities of carbon dioxide can dissolve. The work of the APCRC (the precursor to CO2CRC) demonstrated that in such formations Australia has a potential carbon dioxide storage resource equivalent to many hundreds of years of emissions at the current rate.
There is now a need to undertake more-detailed studies to identify within that resource specific storage spaces that can be used to mitigate emissions from Australia’s major sources of carbon dioxide. CO2CRC has research underway to address this.
The potential for applying carbon dioxide capture and storage to all the major sources depends on their proximity to storage sites. Although more work is needed to fully assess storage potential, the apparent potential in Australia can be summarised as:
- Kwinana/Perth Region: considerable offshore storage potential; onshore potential probably limited.
- Burrup Peninsula: considerable offshore storage potential in saline aquifers.
- Offshore NW Shelf – Timor Sea: an increasing proportion of Australia’s natural gas will be drawn from carbon-dioxide-rich fields, but fortunately in regions where there is a high prospect of finding excellent storage sites.
- Gladstone/Rockhampton – Central Queensland: a large number of small depleted-oil and -gas fields and other traps; need to identify large-capacity options; enhanced coal-bed methane has some potential.
- South-east Queensland: some depleted oil/gas fields and small structures but more assessment of storage options is required; some enhanced coal-bed methane potential.
- Newcastle–Sydney-Wollongong: assessment of the storage opportunities in NSW basins is currently hampered by a lack of information on the deep geology. This shortcoming will be addressed over the next two to three years through a new NSW-CO2CRC program.
- La Trobe Valley: excellent large-scale storage opportunities in the adjacent offshore Gippsland Basin, with a very large capacity in saline aquifers and also depleted oil fields.
- Cooper Basin: significant carbon dioxide source from gas separation; good storage potential but more work is required to establish capacity.
Deep saline formations are considered by the Intergovernmental Panel on Climate Change to have high storage potential world-wide. The storage of carbon dioxide in coals, coupled with enhanced coal-bed methane recovery, is also being investigated. The method has been applied in the United States of America with some success, but has yet to be tested in Australia. The Zero Carbon Power project of Santos/General Electric proposes to test the technology in the Fairview area of Queensland.
Depleted oil and natural-gas fields, which generally have proven geologic traps, reservoirs and seals, are potentially excellent sites for storage of carbon dioxide. Sedimentary basins in Australia where this is likely to be applicable in the future include the offshore Gippsland Basin, as existing fields become depleted over the next 10 to 20 years, and the offshore sedimentary basins of Western Australia, starting in the next 20 to 40 years as major gas fields are depleted. In some circumstances it may be possible to combine geological storage of carbon dioxide with enhanced oil recovery or enhanced gas recovery.
Australia is more advanced than most other countries in the extent to which it has assessed its storage potential, but there is still more work to be done to identify particular economically and technically viable storage sites or reserves.