Wind-to-Hydrogen Project: Advanced Testing & Results

To assure the environmental benefits of hydrogen as a wide-spread future energy carrier, renewable sources of electricity will be used to a large extent to split water into its two constituent parts. NREL is working with the electrolyzer industry and electric utilities to improve the integration and performance of renewable hydrogen production via electrolysis. NREL and Xcel Energy have collaborated to develop, operate and perform a wide range of tests at the Wind-to-Hydrogen (Wind2H2) demonstration project in Boulder, Colorado, USA.

The major Wind2H2 testing, analysis and operation efforts that will be shared are:

• Long-term integrated renewable electrolysis system testing
• Performance of optimized electrolyzer stack and photovoltaic array electrical operating characteristics (with and without power electronics)
• Variable speed wind turbine to electrolyzer stack with power electronics
• Testing of a wind-solar-fuel cell hybrid system
• System operation and performance lessons learned

The latest experimental configuration includes the addition of a 10-cell stack in series with the standard 20-cell stack. This more optimally aligns the electrical operating point of the stacks and the 10 kW photovoltaic array. Now the combined stack and solar array can be tested in a direct connect configuration (without power converter) versus connected via the NREL-built maximum power point tracking power converter. Results from these tests and from optimization of the 10 kW wind turbine for hydrogen production will be reported.

Several upgrades have expanded the Wind2H2 testing capabilities including a stationary 5 kW fuel cell, 13 kg/day PEM electrolyzer and 350 bar hydrogen storage and dispensing.

NREL has recently installed a 13 kg/day PEM electrolyzer alongside the 12 kg/day alkaline system that was part of the original installation. Long duration performance testing of the alkaline and PEM electrolyzers will be compared.

A new 5 kW fuel cell will enable testing of a wind-solar-fuel cell hybrid system. The performance of such a hybrid system will be characterized and presented. The 5 kW stationary fuel cell also provides another option for regeneration of electricity to the grid.

Lessons learned and implications for future commercial system, based on the design, build and testing of the renewable hydrogen system will also be provided. Operational experience with a new 5000 psi (350 bar) filling station will be shared.