About this Research Topic
Solid-oxide fuel cell (SOFC) technology, which usually operates between 650°C and 900°C, can convert various fuels or chemicals into electricity (X-to-power) with high electrical efficiency and long durability. It is also advantageous for the potential of a combined generation of heat, power and even hydrogen. Currently, the commercialization of this technology towards micro CHP units (below 2 kWe and below 1.5 kWth) has significantly advanced in Japan and South Korea and has started in Europe. The applications towards apartment buildings (5 kWe), commercial buildings (50 kWe), data centers (1 MWe), and industrial processes (over 1 MWe) are now under development, integration, and demonstration. In addition, this technology has been featured as the next-generation stationary power-generation technology, which is expected to replace large-scale less-efficient power plants in the long term. The capability of combined power and hydrogen production via SOFC also promotes its application in the transportation sector (e.g., cruise ships or hydrogen refilling station).
Solid-oxide fuel cell can be operated “reversibly” as an electrolyzer by inverting the current direction. Due to the high operating temperature, solid-oxide electrolyzer cells (SOECs) can use electricity to efficiently convert H2O to H2 via steam electrolysis or convert H2O and CO2 to syngas (a mixture of H2, CO, and CO2) via co-electrolysis. The produced H2 or syngas can be further converted to various fuels or chemicals for transportation or industrial sectors. These power-to-X applications are expected to play a significant role in addressing the increasing excess renewable power. This involves the optimization of the operating strategy of SOECs to economically and flexibly handle the variable excess renewable power. The power-to-X applications using SOECs are currently under demonstration in several projects to bring the technology to technology readiness level (TRL) 5-6.
The reversible operation of a solid-oxide cell (rSOC) can be realized by one integrated system, which is facilitated to provide power balancing services for a local grid with high penetration of variable renewable power or standalone renewable power facilities. The design of such a system is quite complicated to consider the differences of mass and energy balances between the SOFC and SOEC operating modes and the operating strategy to handle the expected balancing profiles and increase the cost competitiveness. The rSOC systems are currently under conceptual investigation, with TRL 1-2.
SOFC, SOEC or rSOC applications can be highly integrated with various industrial processes (e.g., gasification processes, power plants, and other chemical processes), due to high operating temperature and adjustable heat production or consumption (by changing the operating voltage). In addition, CO2 capture or utilization is also important for realizing such applications.
In this topic, all system aspects towards SOFC, SOEC, rSOC applications are involved including but not limited to the following subtopics:
• System concept, design, modeling, simulation, development and demonstration,
• Thermo-economic-environmental analysis and optimization,
• Operating and control strategy optimization,
for various SOC based or integrated systems, e.g.,
• Standalone SOC based systems,
• SOC enhanced industrial processes,
• rSOC based systems for grid balancing services or standalone renewable-power facility, and
• SOFC based systems for the transportation sector.
Keywords: Reversible solid-oxide cell, power-to-X, energy storage, process integration, balancing service
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