Systems and methods for energy storage system are provided. The system includes a particle regeneration subsystem for applying electrical energy to regenerate metallic particulate fuel; a fuel storage subsystem for storing metallic particulate fuel, the fuel storage subsystem in fluid communication with the particle regeneration subsystem; and a power generation subsystem for producing electrical energy from the metallic particulate fuel, the power generation subsystem in fluid communication with the fuel storage subsystem; a bearer electrolyte for transporting the metallic particulate fuel through the particle regeneration subsystem, the fuel storage subsystem and the power generation subsystem; and a control unit configured to independently control flow of the bearer electrolyte between the particle regeneration subsystem and the fuel storage subsystem, and the fuel storage subsystem and the power generation subsystem.

Fuel cell systems configured for efficient byproduct recovery and reuse are disclosed herein. In one embodiment, a fuel cell system includes a reformer configured to reform a fuel containing methane (CH.sub.4) with steam to produce a reformed fuel having methane (CH.sub.4), carbon monoxide (CO), and hydrogen (H.sub.2). The fuel cell system also includes a fuel cell configured to perform an electrochemical reaction between a first portion of the reformed fuel and oxygen (O.sub.2) to produce electricity and an exhaust having carbon dioxide (CO.sub.2), water (H.sub.2O), and a second portion of the reformed fuel. The fuel cell system further includes an oxygen enricher configured to generate an oxygen enriched gas and a combustion chamber configured to combust the second portion of the reformed fuel with the oxygen enriched gas.

Fuel cell systems configured for efficient byproduct recovery and reuse are disclosed herein. In one embodiment, a fuel cell system includes a reformer configured to reform a fuel containing methane (CH.sub.4) with steam to produce a reformed fuel having methane (CH.sub.4), carbon monoxide (CO), and hydrogen (H.sub.2). The fuel cell system also includes a fuel cell configured to perform an electrochemical reaction between a first portion of the reformed fuel and oxygen (O.sub.2) to produce electricity and an exhaust having carbon dioxide (CO.sub.2), water (H.sub.2O), and a second portion of the reformed fuel. The fuel cell system further includes an oxygen enricher configured to generate an oxygen enriched gas and a combustion chamber configured to combust the second portion of the reformed fuel with the oxygen enriched gas.

A device for performing electrolysis of water is disclosed. The device may include a semiconductor structure with a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface. The electron guiding layer of the semiconductor structure may include an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material and at least one metal cathode arranged on the surface of the semiconductor structure. The device may further include at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode may include a plurality of quantum dots of In.sub.xGa.sub.(1-x)N material, wherein 0.4≤x≤1. A system including such a device is also disclosed.

An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO.sub.2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then used to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when (1) sufficient low/zero-carbon electricity is available, (2) it is safe to operate the base-generating device, and (3) supplying the alkalinity product will not endanger sea life. Modified BPED systems include features that facilitate autonomous system operations including enhanced maintenance cycle operations and a reduced reliance on external fresh water sources.

An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO.sub.2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then used to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when (1) sufficient low/zero-carbon electricity is available, (2) it is safe to operate the base-generating device, and (3) supplying the alkalinity product will not endanger sea life. Modified BPED systems include features that facilitate autonomous system operations including enhanced maintenance cycle operations and a reduced reliance on external fresh water sources.

An energy storage system includes: a reformer configured to receive natural gas and steam and to output reformed natural gas; a combustion turbine configured to output heated sweep gas; and a molten carbonate electrolyzer cell (“MCEC”) including: an MCEC anode, and an MCEC cathode configured to receive the heated sweep gas from the combustion turbine. The energy storage system is configured such that: when no excess power is available, the combustion turbine receives the reformed natural gas from the reformer, and when excess power is available, the MCEC operates in a hydrogen-generation mode in which the MCEC anode receives the reformed natural gas from the reformer, and outputs MCEC anode exhaust that contains hydrogen.

An energy storage system includes: a reformer configured to receive natural gas and steam and to output reformed natural gas; a combustion turbine configured to output heated sweep gas; and a molten carbonate electrolyzer cell (“MCEC”) including: an MCEC anode, and an MCEC cathode configured to receive the heated sweep gas from the combustion turbine. The energy storage system is configured such that: when no excess power is available, the combustion turbine receives the reformed natural gas from the reformer, and when excess power is available, the MCEC operates in a hydrogen-generation mode in which the MCEC anode receives the reformed natural gas from the reformer, and outputs MCEC anode exhaust that contains hydrogen.

An electrolyzer system and a fuel cell system that include hydrogen blowers configured to compress hydrogen streams generated by the systems. The electrolyzer system includes a steam generator configured to generate steam, a stack of solid oxide electrolyzer cells configured to generate a hydrogen stream using the steam received from the steam generator, a hydrogen blower configured to pressurize the hydrogen stream generated by the stack, and a hydrogen processor configured to compress the pressurized hydrogen stream.

A wide-area power supply system has a small impact on the environment and is highly economical, as a wide-area power supply network that uses hydrogen energy without requiring conventional transmission towers, etc., the wide-area power supply system comprising: a primary power plant; a hydrogen production facility which produces hydrogen by using electricity from the primary power plant; a primary hydrogen storage facility distributed over a wide area; a secondary hydrogen storage facility distributed for each primary hydrogen storage facility; a regional power grid which sends power to power consuming facilities or dwelling units within a residential area; a secondary power generation facility which is installed within the residential area and converts hydrogen transported via the primary hydrogen storage facility or the secondary hydrogen storage facility into electric power; and a transportation means such as a trailer for transporting hydrogen between the hydrogen production facility and the primary hydrogen storage facility, between the primary hydrogen storage facility and the secondary hydrogen storage facility, and between the primary hydrogen storage facility or the secondary hydrogen storage facility and the secondary power generation facility.