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NETL presents the latest edition of its publication that showcases research on emerging energy technologies. NETL Edge shares the latest developments the Lab’s mission to drive innovation and deliver solutions for an environmentally sustainable and prosperous energy future. In this issue, we feature key research and technology development in integrated energy systems for net-zero carbon electricity. Check out the newly released edition of NETL Edge to learn more about combining technology and versatility to optimize energy production and lower emissions, finding answers to carbon storage in by using advanced technologies to examine rock cores, building a strong foundation for integrated energy systems through energy conversion research and more.
Image courtesy of Gas Technology Institute
Photo Caption: Image courtesy of Gas Technology Institute. The new STEP facility, supported by NETL, will house a desk-sized sCO2 turbine that could power 10,000 homes. Key recommendations to guide the operation of a first-of-its-kind testing facility to develop next-generation power plants have been issued by NETL researchers. If successful, testing at this facility will provide a pathway to lower the cost of electricity, shrink the environmental and physical footprint of power generation systems and conserve water.
sCO2 power cycle (indirectly heated)
Turbines are important machines in our nation’s fleet of fossil-fueled power plants, extracting energy from domestic resources and converting it into the electricity we depend on. Turbines can also be key players in conserving resources because they can provide clean energy by using less fuel and generating fewer emissions. In a coal-fueled power plant, fuel is combusted in a large furnace to release heat energy. That energy is then used to heat a boiler that turns water into steam. The steam drives the plant’s turbine, which converts the heat energy into kinetic energy. Inside the turbine, steam flows past the turbine blades causing them to turn, like a windmill or pinwheel, except that turbines are much more sophisticated with hundreds of tightly packed blades. Steam exits the turbine and is cooled and condensed through a heat exchanger so the water can be pumped back for reuse. An axle connects the turbine to a generator that spins around with the turbine. The generator uses the kinetic energy from the turbine to make electricity, which travels out of the plant and eventually powers our businesses, homes, appliances, and more.
Kyle Rozman works with a crack sample in NETL’s load frame.
Because supercritical CO2 (sCO2) power cycles can improve thermal efficiency and enable energy production from domestic fossil fuels with responsible stewardship of the environment, NETL researchers are aggressively investigating how to maximize the service life of materials in sCO2environments. sCO2 power cycles operate similarly to other turbine cycles, but they use CO2 – rather than steam – as the working fluid in the turbomachinery.  In its supercritical state, CO2 remains liquid-like rather than gas-like and has unique properties for energy generation equipment. For example, turbomachinery that uses sCO2 can be very compact and highly efficient, requiring less compression and enabling better heat exchange. sCO2 power cycles operate at very high pressures, which means they operate more efficiently so more energy can be created from less fuel and with a reduced cost. Because sCO2power cycles require higher pressures than traditional power generation systems, the physics, chemistry, and components do not behave as they would in conventional systems.
Temperature contours from CFD simulation of a 300 bar oxycombustor.
NETL researchers are studying supercritical CO2 power cycles to improve thermal efficiency and alleviate adverse environmental impacts of using fossil fuels to generate power—work they hope will someday result in zero emissions and record-breaking efficiencies. This work features a special type of combustion known as oxyfuel combustion (or oxycombustion), in which oxygen rather than ambient air is used to combust fuel. The resulting flue gas is composed of highly concentrated, or supercritical, CO2.