Solid Oxide Cell Technology for Power Generation, Hydrogen Production and Energy Storage
Authors: Ghezel-Ayagh Hossein 
Published: September 2023

The progress in maturation of solid oxide cell technology has led to development of new applications that would explode its presence in many areas, far beyond power generation. The solid oxide cell technology has the potential to have a formidable presence in production of hydrogen and, eventually, long duration storage of electric power.

Following the successful operation of a 200 kW SOFC system under a project supported by Department Energy/NETL, FuelCell Energy (FCE) is pursing the development of SOC based plant configurations from subMW to electrolysis, and further, to energy storage.

Multi-faceted evolution of the technology has been underway since the earlier demonstration of SOFC power plant. FCE has developed state-of-the-art lightweight Compact SOFC Architecture (CSA) stacks that are packaged in compact modules with adaptability for use in a variety of configurations and capacities. The CSA stacks can operate directly on a variety of fuels - natural gas, biogas, and hydrogen- without any modification. FCE’s existing fuel cell pilot manufacturing line for CSA cells and stacks includes robotics and automation such as cell screen printing, interconnect subassembly, seal application, QC, as well as stack assembly and conditioning. Via a design for manufacturing approach, as well as focus on minimization of raw material, recent detailed cost studies show a path to low factory stack production cost (<100/kW) at high volumes (1,000 MW/year). The large market existing for power generation equipment, in the range of 200-300kW, is a significant driver for development of high efficiency SOFC products that would easily cater to early-adopters prior to wide-spread acceptance. The accelerated interest in hydrogen as the fuel source will widen the market for SOFC deployment even more. Under a project supported by DOE, FCE is working on design of MW-class SOFC power plants as future extension of the subMW SOFC plant products.

FCE is developing a first-of-a-kind 250kW Solid Oxide Electrolyzer Cell (SOEC) system with the hydrogen production capacity of 150kg/day. The overarching goal of the project is to verify that the integration of Solid Oxide Electrolysis Cell (SOEC) systems within nuclear plants will maximize the plants’ efficiency and flexibility and will increase their revenue by switching between electric power generation and hydrogen production. Hybrid nuclear-hydrogen production operations are expected to help the present and future nuclear plants diversify and increase profitability.

The 250kW SOEC system is planned to be demonstrated and operated at Idaho National Laboratory (INL). The project will culminate in verification and validation testing and solidify SOEC technology as a low cost and efficient means for hydrogen production integrated within the nuclear power plant environment. The SOEC system will be interfaced with a High-Level front-end Controller (HLC) simulating communications from a nuclear plant and the electric grid. The HLC will determine an optimized hydrogen production schedule to meet all contractual obligations, while maximizing revenue from the integrated operations.

FCE is also developing energy storage systems based on the Company’s Solid Oxide Fuel Cell (SOFC) technology. Reversible Solid Oxide Fuel Cell (RSOFC) technology is suitable for medium to long-duration energy storage achieving high round trip electric efficiencies near 70% (electricity-in to electricity-out) at an expected levelized cycle cost of ≤ $0.05 / kWh-cycle.

FCE is currently conducting operational tests of an RSOFC prototype system to accomplish the of validation and verification of engineering/pilot-scale RSOFC technology in a relevant environment. A bread-board pilot demonstration system is being utilized to verify cell materials and stack design improvements as well as to validate power electronics and system control strategies that will be utilized for optimization of efficiency, transient response, and lifetime characteristics.