Hydrogen-fueled Prius

http://www.llnl.gov/str/June07/Aceves.html

Lawrence Livermore National Laboratory acquired a Prius that had been converted to run on hydrogen by Quantum Fuel Systems Techonologies Worldwide, Inc., of Irvine, CA. The Prius was chosen because it wwas energy efficient and required only a small tank of liquide hydrogen.

1. 1,050 kilometers on a 150 kilogram tank of liquid hydrogen (65 mpg). Hydrogen is cooled to -253°C, does not require a pressure tank, takes up one-third the volume of hydrogen at room temperature (18°C). Drawbacks include significant amount of electricity required to liquefy the hydrogen (about equal to 30% of the energy content of the hydrogen molecule).

2. Liquid hydrogen is very sensitive when warmed only a few degrees.

3. Circuit testing of the Prius took place over a two-week period during January 2007, with group members taking turns driving on a continuous 5 kilometer circuit on the Livermore, CA, site. The test drive was conducted at 40-56 kmph (25-35 mph) because of site speed limits. Under more realistic driving conditions they estimate the Prius would average 88 km per kilogram (55 miles per kilogram).

4. Pressurized hydrogen at 35 megapascals becomes twice as dense when cooled to -150°C. Cooling to -210°C triples the energy density. The liquid hydrogen storage vessel was tested through 900 high-pressure and 100 low-temperature cycles. This is equivalent to driving 480,000 kilometers with a high efficiency vehicle. Even when heated over a fire, pierced by a bullet, dropped from a height of 10 meters - the tank successfully retained liquid nitrogen for at least 60 minutes.

5. Aceves cautions that a great deal more research is needed before the design is ready for mass-production hydrogen vehicles.

 

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1. Help create a clean transportation system based on hydrogen.
2. Group has expertise in mechanical engineering, physics, analytical chemistry, hydrogen storage and use, combustion engineering and modeling and energy modeling.
3. Livermore work is sponsored by DOE's Office of Energy Efficiency and Renewable Energy and is part of DOE's National Hydrogen Storage Project to demonstrate advanced hydrogen storage materials and designs.
4. Current US transportation sector is almost 100% dependent on fossil fuels and transportation accounts for more than 2/3rds of petroleum consumed daily.
5. Zero greenhouse gases and only small amount of nitrogen oxides.

This helps to answer the "why?" but does not address efficiency in use of land, time, resources, finite and renewable resources.