Formed in partnership with Xcel Energy, NREL's wind-to-hydrogen (Wind2H2) demonstration project links wind turbines and photovoltaic (PV) arrays to electrolyzer stacks, which pass the generated electricity through water to split it into hydrogen and oxygen.
The resulting hydrogen is stored for later use at the site's hydrogen fueling station or converted back to electricity (via a hydrogen internal combustion engine or fuel cell) and fed to the utility grid during peak-demand hours.
Located at the National Wind Technology Center near Boulder, Colorado, the Wind2H2 project aims to improve the system efficiency of producing hydrogen from renewable resources in quantities large enough and at costs low enough to compete with traditional energy sources such as coal, oil, and natural gas.
The Wind2H2 project uses two wind turbine technologies: a Northern Power Systems 100-kW wind turbine and a Bergey 10-kW wind turbine. Both wind turbines are variable speed, meaning the blade's speed varies with wind speed. Such wind turbines produce alternating current (AC) that varies in magnitude and frequency (known as wild AC) as the wind speed changes.
The energy from the 10-kW wind turbine is converted from its wild AC form to direct current (DC) and then used by the electrolyzer stack to produce hydrogen from water. The energy from the 100-kW wind turbine is monitored with a power transducer, and stack current on the 33-kW alkaline stack is varied proportionally.
Two HOGEN 40RE polymer electrolyte membrane electrolyzers from Proton Energy Systems and one Teledyne HMXT-100 alkaline electrolyzer produce hydrogen and oxygen from water. NREL examines the issues related to integrating these technologies as well as the operation of electrolyzers with different gas output pressures.
After compressing the hydrogen, it is stored for later use at the site's hydrogen fueling station or converted back to electricity and fed into the utility grid during peak-demand hours.
NREL's research focuses on:
- Exploring system-level integration issues related to multiple electrolyzers that produce hydrogen gas at different pressures
- Evaluating the ability to integrate energy from variable-speed wind turbines and PV arrays directly to the hydrogen-producing stacks of commercially-available electrolyzers
- Determining the system impacts and ability of each electrolyzer technology to accommodate the varying energy input from wind turbines and PV arrays
- Quantifying system-level efficiency improvements and cost reductions by designing, building, and integrating dedicated wind-to-electrolyzer-stack power electronics to enable closer coupling of wind- and PV-generated electricity and electrolyzer stack requirements
- Gaining operational experience of a hydrogen production facility, including the compression of product gas and the use of a hydrogen internal combustion engine to generate electricity during peak demand hours
- Evaluating safety systems and controls for the safe operation of hydrogen production technologies with varying energy input from wind and PV systems
- Demonstrating wind-to-hydrogen system operation to enable cost evaluations/reductions and efficiency improvements
- Exploring operational challenges and opportunities related to energy storage systems and their potential for addressing the electric-system-integration issues associated with variable renewable energy resources.