Toshiba has shipped a 25-megawatt turbine that will be used in the world’s first supercritical oxy-combustion CO2 power cycle generation system that will capture and sequester CO2.
The companies involved in the project say this technology will help commercialize carbon capture technology — which has faced technical and financial obstacles — by making the process more efficient without any increase in the cost of electricity.
The demonstration power plant is being built in La Porte, Texas by Net Power, a collaboration between Exelon Generation, CB&I, and 8 Rivers Capital. Almost two years ago the company announced it had secured funding for the $140 million project.
The technology uses supercritical CO2, as opposed to steam, as a working fluid to drive the turbine. Net Power says the supercritical CO2 system achieves the same level of generating efficiency as a combined-cycle power plant but produces zero emissions. It separates and collects CO2 at high-pressure, which means it doesn’t need separate carbon capture equipment or processes. A major part of this CO2 flow is fed back to the combustor to begin the cycle anew. The remaining part of the CO2 flow can be collected and put into a pipeline for storage, sequestration or reuse.
In an earlier interview with Environmental Leader, Walker Dimmig, a spokesman for Net Power, said this inherent carbon capture system keeps electricity costs low.
“Traditional carbon capture approaches begin by assuming today’s best methods of power generation, such as natural gas combined cycle, are also the best starting point for developing a carbon capture system,” Dimmig said. “So they design additive systems that bolt onto traditional plants to capture, cleanup and then compress their emissions streams. By their very nature, these systems will always be cost-additive to existing technologies: if you add a bunch of equipment, complexity, and processes that require energy, these systems will by necessity lower the efficiency and increase the capital cost of current plants.
The demonstration plant will start operation in 2017. After testing the technology, the companies plan to construct a 250 MW commercial-scale natural gas plant.
Late last month the Department of Energy awarded $80 million for a 10 MW, six-year pilot project that will test supercritical CO2’s use in gas turbines to improve efficiency. The Gas Technology Institute (GTI), Southwest Research Institute (SwRI) and General Electric Global Research will manage the $110 million project.