4.1 Technology selection
The selection of a technology was significantly influenced by both government policy requirements and grant funding availability.
Work in relation to development of a coal-fuelled power station at Wandoan dates back to 1977. Early studies proposed traditionalcombustion as the preferred generation technology. However since 2005, Government policy has precluded this option with a requirement that coal-fuelled power generation projects adopt CCS technology.
Grant funding availability
The Clean Coal Special Technology Agreement Act 2007, a legislated agreement between the Queensland Government and ACALET, stipulated that a significant amount of funding should be directed to an IGCC project.
Furthermore, the Australian Government's CCS Flagship Program8 potentially offered large amounts of funding for projects that met essential eligibility criteria which included project scale, technology maturity and delivery timeframe.
- Project scale eligibility: This included being at a capacity that could be rapidly and effectively escalated to commercial deployment in and would demonstrate a high level of CO2 capture (moving towards 90 per cent during the project life). The scale also needed to give OEMs and sufficient confidence to provide performance and process guarantees for their technology.
- Technology maturity eligibility: The technology selected needed to be at a suitable degree of maturity to enable its scale-up and deployment in a large-scale demonstration project.
- Timeframe eligibility: The project needed to demonstrate a financial decision could be reached within a timeframe that would allow it to be operational from 2015.
4.1.1 IGCC technology selection
Prior to the pre-feasibility study, Stanwell analysed the options and 9, some with CO2 capture technology were GE, Shell, Siemens, Conoco Phillips, Southern and Mitsubishi Heavy Industries (MHI).market conditions for CO2 capture technology at industrial scale for the generation sector. Prospective suppliers of Integrated Combined Cycle (IGCC) plant
Stanwell identified GE's IGCC with pre-combustion CO2 capture as the preferred technology for the following reasons:
- A review of the three main technology paths for CO2 capture from fossil-fuelled power generation10 identified IGCC with pre-combustion capture to be the only industrial scale generation technology available for deployment and delivery of operations between 2015 and 2020.
- GE's IGCC with pre-combustion capture technology was consistent with the essential eligibility criteria of the CCS Flagships Program regarding project scale, technology maturity and timeframe.
- GE's power station technology can capture high levels of CO2 emissions at industrial scale, with plants currently operating at 90% capture rates.
- Compared with the Edwardsport project the scale-up factor for the gasifier is approximately 1.4 and for the radiant cooler it is less than this value. This level of scale is considered to be manageable for the GE technology.
- GE can provide IGCC with CO2 capture technology on a commercial basis with bankable and warranties.
- GE was selected by to provide IGCC technology for their IGCC power station, which is scheduled for commercial operation in 2012.
- GE expressed interest in developing a 50Hz reference site for their IGCC technology.
- GE was prepared to back their technology by taking an equity participant role in the project development.
- At the time of project conception, Siemens, Conoco Phillips and did not appear to have achieved a high level of design integration for IGCC plants.
MHI have built a 275MW demonstration IGCC plant using air-blown gasification technology. While this option facilitates high fuel efficiency and performance without CO2 capture, it is less suited to the required high levels of CO2 capture in comparison with the oxygen-blown gasification technology (as proposed for Wandoan Power).
During the pre-feasibility study an update to the original analysis including a global CCS project survey was conducted. The results from the updated analysis supported the original assessment and are included in Appendix 1.
4.1.2 Technology alternatives
A review of alternatives technologies for CO2 captured was conducted in the context of the essential eligibility criteria of the CCS Flagships Program which included project scale, technology maturity and delivery timeframe (as discussed in section 4.1).
The retrofit potential of post combustion capture (PCC) andtechnologies may at first appear to make them a seemingly attractive option to produce the necessary quantities of CO2 for testing the geological storage of CO2 at industrial scale compared to a greenfield development like IGCC with pre-combustion capture. The potential cost savings of a retrofit project are a result of using the flue gas from an existing power plant. However given the current status of development of PCC and oxy-fuel combustion technologies this approach:
- Will likely result in a retrofit plant that does not significantly progress the development of the respective technology toward the ultimate goal of high levels of capture with low energy penalty required for commercial deployment of CCS.
- Results in a high cost of CO2 per unit captured as using a slipstream on a large plant offers easier but limited integration, creating a high energy penalty and operating cost.
- Would be an inefficient use of the capital investment as the plant will likely be run for as short a time as possible (may be retired in five years).
- Does not explore integration/operability issues with the CO2 transport and storage element of the style of plant that will ultimately be deployed commercially. Higher levels of capture and integration are considerably more complex.
- May not readily produce sufficient quantities of CO2 at the required quality and availability for testing large-scale geological storage because these capture processes themselves are still currently undergoing process validation at smaller scale than that required for a large-scale CCS project.
- Has significant scale-up and cost risk because these capture processes have never been in use at large-enough scale in any plant to date.
- Would still likely require two years of project development to reach (i.e. pre-feasibility study followed by a and front end engineering and design).
Further discussion of the potential issues for a retrofit PCC or oxy-fuel combustion project to produce sufficient quantities of CO2 for testing the geological storage of CO2 at large scale (required for CCS Flagships eligibility) is included in Appendix 2.
8 For more information on the CCS Flagships Program refer http://www.ret.gov.au/energy/Documents/ clean-energy-program/CCS%20Flagship%20Program%20guidelines.pdf
9 A general description of the IGCC process is included as Appendix 3
10 The three main technology paths for CO2 capture are pre-combustion capture, oxy-fuel combustion and post combustion capture (PCC).