The U.S. Department of Energy’s (DOE) Office of Fossil Energy (FE) has selected seven Coal FIRST (Flexible, Innovative, Resilient, Small, Transformative) conceptual designs to receive $7 million and proceed with preliminary front-end engineering design (pre-FEED) studies. These designs have been selected from 13 conceptual design studies that were completed by 11 different recipients as part of the first phase of the effort.
The DOE selected the designs as a part of its Coal FIRST initiative, which seeks to advance coal power generation beyond today’s state-of-the-art capabilities and make coal-fired power plants better adapted to the evolving electrical grid. Research and development resulting from this initiative will underpin coal-fired power plants that are capable of flexible operations to meet the needs of the evolving grid, use innovative cutting-edge components that improve efficiency and reduce emissions, provide resilient power to Americans, are small compared to today’s conventional utility-scale coal, and will transform how coal technologies are designed and manufactured.
Descriptions of the seven conceptual designs selected to proceed are listed below:
(1) 8 Rivers Capital
(Durham, NC) will perform a pre-FEED study on a 300 megawatt (MW) zero emission Allam Cycle coal plant. The Allam Cycle has the potential to produce electricity at a lower cost than conventional fossil generation with greater than 97 percent carbon dioxide (CO2) capture and near-zero air emissions. In this project, the team will integrate coal gasification and the Allam Cycle core technology currently being proven by NET Power (a separate entity advancing the Allam Cycle on natural gas).
Key technological benefits of this design include net efficiency in the mid-to-high 40s; higher heating value with carbon capture; ramping speeds in-line with natural gas combined cycle technology, with the potential to exceed that performance; significant water savings (50 percent to 60 percent) compared with integrated gasification combined cycle technology; fuel flexibility; and the ability to store electricity as chemicals when power is in low demand.
(2) Allegheny Science & Technology Corporation (AST) (Pittsburgh, PA) will partner with the Worley Parsons Group and Catalyte to conduct a pre-FEED study for a polygeneration platform to advance the objectives of Coal FIRST. AST’s system prepares raw coal for fluidization via a moderate temperature bubbling bed devolatilization and drying process.
The process increases overall system adaptability by facilitating a wider range of acceptable coal feedstocks—including various waste coal streams—for use in producing synthesis gas (syngas) in a fluidized bed gasifier, which provides the operational flexibility needed to handle the heterogeneity of both feedstocks and electrical demand. In addition, the approach includes a water-gas shift reactor to optimize the synthesis ratio for fuel production and support a range of pre-combustion capture options.
(3) Barr Engineering Co. (Minneapolis, MN) will team with Doosan Heavy Industries, the University of North Dakota Institute for Energy Studies, Microbeam Technologies Inc., and Envergex LLC to complete a pre-FEED study on a future plant concept that combines a state-of-the-art, ultra-supercritical (USC) 250-MW coal-fired power plant with an 80-MW natural gas-fired turbine and energy storage.
The plant design will comprise of unique features to enable rapid start-up and load changes, including a combustion turbine with an inherently fast start-up and ramp rate capability. When power demand is lower than minimum load, surplus electricity will be stored in the energy storage system, which will handle the initial ramp-up for morning or evening peak demand.
(4) CONSOL Coal Company LLC (Canonsburg, PA) will team with WorleyParsons Group, Inc. and Farnham & Pfile Engineering, Inc. to complete a pre-FEED study that combines high efficiency with flexible load-cycling capabilities. The project supports the conceptual design of a novel coal-fired power generation cycle utilizing a pressurized fluidized bed combustor and supercritical steam cycle with Benefield CO2 capture. The power cycle will aim to achieve greater than 40 percent efficiency as well as the ability to operate flexibly and accept a broad range of coal qualities (including waste coals).
Moreover, because combustion is carried out at elevated pressure, the technology is well-suited to reduce the cost and energy requirements for CO2 separation. This project will build upon the team’s previous efforts by producing a plant design that is consistent with DOE’s common design basis and optimized to meet the needs of today’s power markets, including efficiency (both in CO2 capture-ready configuration and with CO2 capture installed), ramp rate, cold/warm start time, turndown ratio, air emission rates, and solid and liquid disposal requirements.
(5) Echogen Power Systems Inc. (Akron, OH) will partner with the Gas Technology Institute, the Electric Power Research Institute, and Louis Perry Associates to complete a pre-FEED study of an advanced technology coal-fired power plant integrating three innovative technologies: supercritical carbon dioxide (sCO2) power cycles, pressurized fluidized bed combustion, and electrothermal energy storage (ETES).
Supercritical CO2 power cycles offer substantial benefits over conventional and even advanced steam Rankine cycles, including higher efficiency, smaller footprint, and water-free operation. The CO2-based ETES system leverages the sCO2 power cycle infrastructure to add flexible energy storage for both thermal energy and electrical power in a set of thermal reservoirs that can be discharged when power demand exceeds baseload capacity. These technologies will deliver the key plant characteristics of compactness, efficiency, modularity, and operational flexibility needed for coal-fired power plants to remain competitive in a rapidly changing energy market.
(6) Electric Power Research Institute Inc. (EPRI) (Palo Alto, CA) will perform a pre-FEED study for a ~300-MW-electric pulverized-coal power plant with superheat (SH) temperature/reheat temperature/SH outlet pressure with high net plant efficiency, capable of flexible and low-load operation.
The cycle will optimize the trade-off between maximum efficiency and minimum MW rating to determine the minimum rating of the synchronous steam turbine, while maintaining the high-pressure steam turbine inlet size within design and manufacturing limits regarding blade length and rotor diameter. Pressure-part materials will be designed to maximize the operational flexibility of the unit during the conceptual design phase.
The power plant concept will provide an optimized regime for fast start-up, load changes, and dynamic cycling, to enable enhanced flexibility in response to grid requirements, savings of initial power consumption at start-up, and a more agile power plant that can provide more opportunities to bid in power markets. To achieve these goals, the EPRI team includes the technical resources of General Electric Steam Power and AECOM.
(7) Nexant Inc. (San Francisco, CA) will perform a pre-FEED study for a modular power plant utilizing a coal-based “fluid” in either slurry or micronized form. The plant will couple a highly efficient and flexible reciprocating engine with a conventional gas turbine in a reheat Brayton cycle, while also including a steam (Rankine) bottoming cycle to maximize the thermal efficiency.
A key aspect of this concept is the maturity of all the component technologies (i.e., low-firing temperature turbine; cheap/simple bottoming cycle; coal-slurry firing demonstrated in direct injection carbon engines), indicating a potential for minimal additional technology development. The project team includes Nexant, Bechtel Infrastructure & Power Corporation, and CZERO Inc.
The Office of Fossil Energy funds research and development projects to reduce the risk and cost of advanced fossil energy technologies and further the sustainable use of the Nation’s fossil resources. To learn more about the programs within the Office of Fossil Energy, visit the Office of Fossil Energy website or sign up for FE news announcements. More information about the National Energy Technology Laboratory is available on the NETL website.