A Japanese study has introduced an advanced method for capturing carbon dioxide (CO2) emissions from thermal power plants, which promises significant cost savings and improved profitability. The proposed system uses a power-to-heat amine-based post-combustion CO2 capture (PCC) technique with solvent storage, leveraging fluctuating electricity prices to optimise operations.
Key Features of the New CO2 Capture System
This novel system integrates solvent storage tanks and a heat pump that utilises cheap electricity during peak power generation periods to desorb CO2. By capturing CO2 while the power plant operates and using inexpensive electricity for CO2 desorption, the system reduces the average energy cost for CO2 stripping and compression by approximately 30% compared to conventional methods. This results in a 15% increase in the net present value (NPV) of the plant, demonstrating its economic feasibility.
Advantages Over Traditional Systems
Traditional amine-based PCC systems face high operational costs due to the energy-intensive process of regenerating the amine solvent used to capture CO2. The new system mitigates this by using low-cost electricity to power a heat pump, which generates the necessary heat for the CO2 desorption process. This approach not only lowers operational costs but also maximises power generation during high-demand periods, boosting overall revenue.
Economic and Environmental Impact
The study’s mathematical model, which optimised the system’s operations based on real annual electricity prices, showed promising results even for power plants with a low capacity factor (less than 30%). Retrofitting existing natural gas combined cycle (NGCC) plants with the new PCC system yielded positive NPVs, suggesting that it can be economically viable without additional incentives such as CO2 credits or grant funding.
However, the study highlighted that high CO2 prices (between $350 and $400 per tonne) are necessary to make carbon capture and storage (CCS) economically attractive under current conditions. Therefore, reducing the capital expenditure (CAPEX) of PCC systems is essential to encourage widespread adoption.
Enhancing Power Supply Reliability
By converting excess electricity generated during periods of high renewable energy supply into stored chemical energy, the new system can act as a cost-effective energy storage solution. This capability helps balance the grid, reduce curtailment of renewable energy sources, and ensure a reliable power supply.
The innovative power-to-heat amine-based PCC system with solvent storage offers a cost-effective and economically sustainable solution for capturing CO2 emissions from thermal power plants. By utilising cheap electricity for CO2 desorption, it reduces operational costs and enhances profitability, making it a viable option for the future of clean energy. This system supports the transition to a low-carbon economy by providing a reliable and flexible power source that integrates seamlessly with variable renewable energy supplies.
Source
Power-to-heat amine-based post-combustion CO2 capture system with solvent storage utilizing fluctuating electricity prices, Applied Energy, 2024-08-15
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