The Hybridisation of Concentrated Solar Thermal project achieved the world’s first practical demonstration of pilot scale Post-Combustion Carbon dioxide capture (PCC) process integrated with solar thermal energy and demonstrates an important low emissions energy solution to achieving substantial emissions reductions from Australian coal fired electricity generation with the potential for large scale deployment of solar thermal fields in Australia.
Many of the challenges faced in the experimental phase related to managing the solar thermal plant to achieve the process conditions of an existing PCC process. Conventional PCC processes have been developed with the view to integrating with the steam cycle of the power plant and have thus been constrained to a narrow set of process parameters defined by the steam temperatures and pressures available from the power plant. When the heat sources is external to the power plant, as is the case with an autonomous solarised PCC process, these existing constraints are no longer relevant as the solar plant is capable to producing a very broad range of temperature and pressure profiles. This creates the opportunity for new novel capture processes and technologies for capturing CO2 from existing and new coal fired power stations.
The experimental phase of the project identified a range of key learnings including the need for improved dynamic modelling capabilities when integrating variable energy sources such as solar with processes designed for steady state operation. The key process engineering software and design techniques employed by the project engineers are fundamentally based on steady state conditions. Therefore the selection of valves, pumps, and control strategies were not always well suited to the needs of a variable process like solar energy production where the solar resource fluctuates from day to day and even hour to hour.
The experimental phase of the project identified some of the challenges in system start-up when integrating a variable solar energy source with post combustion capture. The energy requirements to get all of the system components to temperature was substantial and although the small size of the plant exacerbated this challenge (and may not be fully representative of a large scale system) the need to carefully select materials and adequately insulate sources of heat loss is paramount to ensure the successful integration of solar thermal systems with CCS.
Report: Hybridisation of Concentrated Solar Thermal with Carbon Capture and Storage
This project demonstrated CST providing the complete heat requirement for CO2 capture, by continuous absorption of CO2 in the absorber, intermediate storage of the CO2 rich solvent in a vessel as an alternative to thermal storage, followed by regeneration of the solvent by concentrated solar thermal energy.
Australia has abundant solar energy and coal resources with 80% of Australian electricity generation currently based on coal. Synergies resulting from a hybrid solar-carbon capture technology could harness these abundant resources to provide low emissions energy for the Australian community.
The Hybridisation of Concentrated Solar Thermal project involved CSIRO investigating the feasibility of using concentrated solar thermal (CST) energy in a post-combustion carbon dioxide capture (PCC) process at coal-fired (and gas) power stations.
It aimed to develop a new solar thermal reboiler which regenerates the liquid absorbents used in PCC devices to absorb the carbon dioxide emitted when fossil fuels are burned in power stations.
CSIRO designed and constructed a pilot-scale solar thermal reboiler for thermal regeneration of liquid absorbents, and a small solar trough field at Vales Point Power Station for integration with an existing CSIRO carbon capture pilot plant
Both were tested at a CSIRO-operated carbon capture plant located at Delta Electricity’s Vales Point Power Station in NSW.
This project is the world’s first practical demonstration of pilot-scale PCC integrated with solar energy.
The development of this solar thermal-driven autonomous carbon capture process effectively transforms any existing coal-fired power station into a capture-ready plant, with the potential of making solar thermal technologies an integral part of transforming Australia’s power generation fleet.