WIND-TO-HYDROGEN ENERGY PILOT PROJECT: BASIN ELECTRIC POWER COOPERATIVE
In an effort to address the hurdles of wind-generated electricity (specifically wind's intermittency and transmission capacity limitations) and support development of electrolysis technology, Basin Electric Power Cooperative (BEPC) conducted a research project involving a wind-to-hydrogen system. Through this effort, BEPC, with the support of the Energy & Environmental Research Center at the University of North Dakota, evaluated the feasibility of dynamically scheduling wind energy to power an electrolysis-based hydrogen production system.
The goal of this project was to research the application of hydrogen production from wind energy, allowing for continued wind energy development in remote wind-rich areas and mitigating the necessity for electrical transmission expansion.
Prior to expending significant funding on equipment and site development, a feasibility study was performed. The primary objective of the feasibility study was to provide BEPC and The U.S. Department of Energy (DOE) with sufficient information to make a determination whether or not to proceed with Phase II of the project, which was equipment procurement, installation, and operation.
Four modes of operation were considered in the feasibility report to evaluate technical and economic merits. Mode 1 - scaled wind, Mode 2 - scaled wind with off-peak, Mode 3 - full wind, and Mode 4 - full wind with off-peak
In summary, the feasibility report, completed on August 11, 2005, found that the proposed hydrogen production system would produce between 8000 and 20,000 kg of hydrogen annually depending on the mode of operation. This estimate was based on actual wind energy production from one of the North Dakota (ND) wind farms of which BEPC is the electrical off-taker. The cost of the hydrogen produced ranged from $20 to $10 per kg (depending on the mode of operation).
The economic sensitivity analysis performed as part of the feasibility study showed that several factors can greatly affect, both positively and negatively, the "per kg" cost of hydrogen.
After a September 15, 2005, meeting to evaluate the advisability of funding Phase II of the project DOE concurred with BEPC that Phase I results did warrant a "go" recommendation to proceed with Phase II activities.
The hydrogen production system was built by Hydrogenics and consisted of several main components: hydrogen production system, gas control panel, hydrogen storage assembly and hydrogen-fueling dispenser
The hydrogen production system utilizes a bipolar alkaline electrolyzer nominally capable of producing 30 Nm3/h (2.7 kg/h). The hydrogen is compressed to 6000 psi and delivered to an on-site three-bank cascading storage assembly with 80 kg of storage capacity. Vehicle fueling is made possible through a Hydrogenics-provided gas control panel and dispenser able to fuel vehicles to 5000 psi.
A key component of this project was the development of a dynamic scheduling system to control the wind energy's variable output to the electrolyzer cell stacks. The dynamic scheduling system received an output signal from the wind farm, processed this signal based on the operational mode, and dispatched the appropriate signal to the electrolyzer cell stacks. For the study BEPC chose to utilize output from the Wilton wind farm located in central ND.
Site design was performed from May 2006 through August 2006. Site construction activities were from August to November 2006 which involved earthwork, infrastructure installation, and concrete slab construction. From April - October 2007, the system components were installed and connected.
Beginning in November 2007, the system was operated in a start-up/shakedown mode. Because of numerous issues, the start-up/shakedown period essentially lasted until the end of January 2008, at which time a site acceptance test was performed.
Official system operation began on February 14, 2008, and continued through the end of December 2008. Several issues continued to prevent consistent operation, resulting in operation of the system in fits and starts.
During the operational period, three ramp tests were performed on the electrolyzer cell stacks to evaluate cell stack degradation, if present. In addition, from December 23 - 30 2008, the hydrogen system was operated using Mode 1 protocol.
From February 14, 2008 - December 31, 2008, the system produced a total of just less than 26,000,000 liters (2320 kg), including approximately 3,300,000 liters (295 kg) of hydrogen during Mode 1 operation.
Unfortunately, the chronic shutdown issues prevented consistent operation and, therefore, did not allow for any accurate economic analysis as originally intended. With that said, much valuable experience was gained in the form of "lessons learned," and the project served as an extremely valuable platform for educating the public.