You’ve probably heard about carbon capture and storage (CCS), a suite of technologies designed to capture and store carbon dioxide (CO2) from power plants and industrial sources. Because CCS can be applied to existing and new coal-fired power plants to help them burn cleaner, it’s a big part of President Obama’s Climate Action Plan and his all-of-the-above energy strategy.
What you may not know is that there are a lot of moving parts to CCS. And one of the more expensive parts is the actual CO2 capture process. In fact, driving down the cost of carbon capture is a key to the commercial deployment of CCS.
Housed under the multi-pronged Carbon Capture and Storage and Power Systems program, the Office of Fossil Energy (FE) has several research and development (R&D) areas geared to CCS development, including research to reduce the cost of capture. And one of those areas is Advanced Combustion R&D.
This research is focused on developing advanced combustion technologies – ways to burn fuels like coal in a way that’s more efficient, cleaner and cost-effective.
These pathways include pressurized oxy-combustion and chemical looping processes. In oxy-combustion, the air that’s combusted is replaced with a mixture of oxygen and recycled flue – or exhaust – gas and/or water for temperature control. The flue gas that’s not recirculated is rich in CO2 and water vapor, which makes it easily separated, producing a stream of CO2 ready for utilization or sequestration.
Researchers are also exploring technologies to lower the cost of oxy-combustion, including oxygen and ion transport membranes. These technologies could provide a low-cost supply of pure oxygen needed for the oxy-combustion process.
Another novel concept under development is the chemical looping combustion process, which splits combustion into separate chemical reactions. The advantage of this process is that the CO2 is concentrated, once the water is removed, and not diluted with nitrogen gas. That means that no air separation plant or external CO2 separation equipment is required.
FE’s ongoing research was recently bolstered by the selection of four projects to develop advanced coal combustion technologies with built-in CO2 capture. With nearly $26 million in Energy Department funding and $11 million in backing from industry, universities, and other research institutions, these projects are designed to move us toward our goal of capturing 90 percent of CO2 emissions from a new or existing coal power plant – at a cost of less than $40/tonne of CO2 captured.
Coal provides nearly 40 percent of our electricity, and it’s projected to remain an important part of our energy mix into the foreseeable future. By developing new technologies that help coal-fired power plants to burn cleaner, FE is working to ensure that power plants meet environmental standards – and that coal will remain a robust part of our energy portfolio in a carbon-constrained world.