APS Alternative Fuel (Hydrogen) Pilot Plant - Monitoring System Report
The U.S. Department of Energy’s (DOE’s) Advanced Vehicle Testing Activity (AVTA), along with Electric Transportation Applications and Arizona Pubic Service (APS), is monitoring the operations of the APS Alternative Fuel (Hydrogen) Pilot Plant to determine the costs to produce hydrogen fuels (including 100% hydrogen as well as hydrogen and compressed natural gas blends) for use by fleets and other operators of advanced-technology vehicles. The hydrogen fuel cost data will be used as benchmark data by technology modelers as well as research and development programs. The Pilot Plant can produce up to 18 kilograms (kg) of hydrogen per day by electrolysis. It can store up to 155 kg of hydrogen at various pressures up to 6,000 psi. The dispenser island can fuel vehicles with 100% hydrogen at 5,000 psi and with blends of hydrogen and compressed natural gas at 3,600 psi. The monitoring system was designed to track hydrogen delivery to each of the three storage areas and to monitor the use of electricity on all major equipment in the Pilot Plant, including the fuel dispenser island. In addition, water used for the electrolysis process is monitored to allow calculation of the total cost of plant operations and plant efficiencies. The monitoring system at the Pilot Plant will include about 100 sensors when complete (50 are installed to date), allowing for analysis of component, subsystems, and plant-level costs. The monitoring software is mostly off-the-shelve, with a custom interface. The majority of the sensors input to the Programmable Automation Controller as 4- to 20-mA analog signals. The plant can be monitored over of the Internet, but the control functions are restricted to the control room equipment. Using the APS general service plan E32 electric rate of 2.105 cents per kWh, during a recent eight-month period when 1,200 kg of hydrogen was produced and the plant capacity factor was 26%, the electricity cost to produce one kg of hydrogen was $3.43. However, the plant capacity factor has been increasing, with a recent one-month high of 49%. If a plant capacity factor of 70% can be achieved with the present equipment, the cost of electricity would drop to $2.39 per kg of hydrogen. In this report, the power conversion (76.7%), cell stack (53.1%), and reverse osmosis system (7.14%) efficiencies are also calculated, as is the water cost per kg of hydrogen produced ($0.10 per kg). The monitoring system has identified several areas having the potential to lower costs, including using an reverse osmosis system with a higher efficiency, improving the electrolysis power conversion efficiency, and using air cooling to replace some or all chiller cooling. These activities are managed by the Idaho National Laboratory for the AVTA, which is part of DOE’s FreedomCAR and Vehicle Technologies Program.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - EE
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 911000
- Report Number(s):
- INL/EXT-05-00502; TRN: US200724%%374
- Country of Publication:
- United States
- Language:
- English
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