NREL, Excel Energy Launch Experimental Wind-to-Hydrogen Energy System

GOLDEN, CO – Excel Energy, the large Minneapolis-based Midwestern gas-and-electricity utility, last month joined forces with researchers at the National Renewable Energy Laboratory here in an experimental wind-to-hydrogen energy production system.

It’s the second wind-to-hydrogen project with links to Minnesota: In August, the University of Minnesota announced plans for a wind-to-hydrogen-to-ammonia program (H&FCL Sept. 06). Other wind-to-hydrogen programs have been announced for Prince Edward Island in Canada (H&FCL May 05); for Utsira Island in Norway (H&FCL Aug. 04); and Hovik, Norway (H&FCL Sept. 01).

The schematic layout of the Excel-NREL Wind-to-Hydrogen System.

The “Wind2H2 Project” at NREL’s brand-new National Wind Technology Center near Boulder links two wind turbines - a 100 kW Northern Power unit and a 10 kW Bergey machine - to three different electrolyzers, two 5 kW PEM Proton Energy electrolyzers and one 50 kW alkaline Teledyne water splitter. The combined hydrogen output of, on average, 20 kg of hydrogen/day is compressed to ultimately 3,500 psi and stored in four advanced-technology compressed storage tanks capable of holding a total of 85 kg of hydrogen.

NREL’s leader of the project, Ben Kroposki, told H&FCL the output varies basically with “which configuration we are running” - one or both of the wind turbines; which, or all, of the three electrolyzers. From there, the hydrogen is pipelined to a 50 kW internal ombustion generator set made by Hydrogen Engine Center (Sept., Oct. 04, June, Oct. 06) and, in parallel, to a 5 kW Plug Power Gen-Core fuel cell. Both feed ac power to the utility grid. Future plans also call for construction of a hydrogen fueling station for cars and trucks (See diagram).

The basic idea behind the $2 million, two-year experiment is to provide energy storage and backup for intermittently blowing renewable wind energy that gives off zero emissions and is totally climate-friendly. Excel is providing about $1.3 million, and DoE is contributing about $750,000.

The overall efficiency of wind to electricity to hydrogen and back to electricity is dictated largely by the efficiency of the generator, the Hydrogen Engine Center’s internal combustion engine genset. The current ballpark figure is about 30% which Kroposki acknowledges is pretty low “but if we replaced it with a fuel cell we would have much better efficiency.”

However, efficiency isn’t the only criterion; cost is another in any future commercial/industrial operation. “Batteries may be much more expensive,” says Kroposki. “That’s why we will be (studying) a variety of energy storage options.”

The actual cost of the hydrogen produced is pretty high, around $5.50/kg, but it certainly isn’t the end of the road: DoE’s long-term goal over the next decade or so is $2-3/kg.

For the time being, NREL is holding off on building a hydrogen fueling station, basically because “there are no hydrogen cars in Colorado,” adds Kroposki. “There’s no big need for it." He estimates the cost for a station at around $100,000 to $200,000 adding that it won’t be considered in earnest “until we are a little more definitive.”

“The project allows our researchers to compare different types of electrolyzers and work on increasing the efficiency of a wind-to-hydrogen system,” said NREL director Dan Arvizu during an inaugural tour of the new facility in mid-December for a handful of reporters, environmental leaders, government officials and Excel Energy manager.

“Today we begin using our cleanest source of electricity - wind power - to create the perfect fuel, hydrogen,” added Xcel Energy chairman and president and CEO, Richard C. Kelly.

The two partners expect to provide a public update of how the system is performing this summer, and results will also be shared with the Hydrogen Utility Group, a group of ten utilities interested in hydrogen as a utility energy vector, and the National Hydrogen Association (NHA) set up last year (H&FCL Jan. 06).

Excel Energy has 20 years experience with wind power. It’s predecessor, Northern States Power, built its first commercial-scale windfarm with three 65 kW turbines in 1986 in Minnesota, and the company says it is the nation’s largest provider of wind energy to retail customers, buying more than 1,100 MW of wholesale wind power.

Contacts: NREL, George Douglas, 303/275-4096, George_Douglas@nrel.gov; Xcel Energy media relations, Denver, 303/294-2300, www.xcelenergy.com