GOLDEN, Colorado, USA, July 11, 2007.
A wind‑to‑hydrogen demonstration project will link turbines to electrolyzers, in a project to improve the system efficiency of producing hydrogen from renewable resources in quantities large enough to compete with traditional energy sources.
The National Renewable Energy Laboratory and Xcel Energy launched the ‘Wind2H2' demonstration project at the National Wind Technology Center in Golden, Colorado. Electricity generated from the turbines is passed through water to split the liquid into hydrogen and oxygen, and the hydrogen is stored for later use to generate electricity from an internal combustion engine or a fuel cell.
The Wind2H2 project uses two turbine technologies: a Northern Power Systems 100 kW turbine and a Bergey 10 kW turbine. Both are variable speed (blade speed varies with wind speed) and both produce AC electricity that varies in magnitude and frequency (‘wild AC’) as wind speed changes.
The energy from the Bergey turbine will be converted to DC and then used by the electrolyzer stack to produce hydrogen from water. Energy from the NPS turbine will be picked from its existing controller, which produces a DC bus between 750 and 800 volts, which is too high for electrolyzer stacks and requires power electronics to make the DC‑DC conversion.
Two HOGEN 40RE proton exchange membrane electrolyzers from Proton Energy Systems and one Teledyne HMXT‑100 alkaline electrolyzer will produce hydrogen and oxygen from water. NREL will examine the issues related to the integration of these technologies as well as the operation of electrolyzers with different gas output pressures.
After compressing the hydrogen, it will be stored for later use in a hydrogen internal combustion engine where it will be converted to electricity, say project organisers. The electricity will be fed into the utility grid during peak demand hours.
NREL research will focus on exploring system‑level integration issues related to multiple electrolyzers that produce hydrogen gas at different pressures. It will also evaluate the ability to integrate energy from variable‑speed turbines directly to the hydrogen‑producing stacks of commercially‑available electrolyzers and will determine system impacts and ability of each electrolyzer technology to accommodate the varying energy input from wind turbines and solar photovoltaics.
“The Wind2H2 project offers many benefits,” NREL claims. “It allows researchers to explore how to make hydrogen without producing GHG or other harmful by‑products. Currently, most hydrogen is ‘reformed’ from natural gas or other fossil fuels by stripping out the hydrogen atoms, thereby creating GHG emissions and eliminating some of the environmental benefits.
