The Hurdles of Hydrogen | Green Energy News

January 2, 2005 – Vol.9 No.41

THE HURDLES OF HYDROGEN.

Of all the technologies that could become the replacement for the engine under the hood of our cars, the hydrogen fuel cell seems the most difficult (and currently the most expensive) to commercialize.

Yet despite all the difficulties - all the hurdles - hydrogen fuel cell vehicles continue to be developed, although not with the vigor of a few years ago.

One of the technological hurdles is operating the vehicles in below-freezing temperatures. Honda has said it has solved the problem. Now Hyundai has claimed the same achievement.

Hyundai’s new Tucson FCEV (Fuel Cell Electric Vehicle) is capable of starting after being subject to -4 degrees F (-20 C) for five days. The SUV is more powerful, at 80 kilowatts, than its predecessor, the Santa Fe FCEV, with only 75 kW. More power boosts maximum speed to 93 miles per hour (150 kph). The older vehicle would top out at 77 miles per hour (124 kph).

Tucson’s fuel cell is from UTC Fuel Cells. Its electric drive from Enova Systems.

Range is extended to 186 miles (300 kilometers) between refillings of gaseous hydrogen in its 40 gallon (152 liter) pressurized tanks. The Santa Fe FCEV had only 72 liters of hydrogen on board.

However, 186 miles between refuelings isn’t nearly what drivers expect. They want 300 miles or so.

The issue of range has to do, in part, with the amount of hydrogen a vehicle can store (safely) under pressure.

GM has revealed a next generation fuel cell vehicle that the company says will travel that 300 miles.

The appropriately named Sequel achieves this range by carrying 8 kilograms of hydrogen in three carbon fiber tanks pressurized to 10,000 pounds per square inch - the highest in any fuel cell vehicle.

The SUV is propelled by electric hub motors. All electronic drive-by-wire systems replace conventional mechanical and hydraulic steering and braking systems. As with all fuel cell vehicles, Sequel is a hybrid with a powerful lithium ion battery pack to boost performance, range and store captured energy from braking.

GM would probably rather not have a vehicle with 10,000 psi fuel tanks, thus hydrogen storage at low pressures in metal hydrides will be addressed in a new joint venture research project between the company and the U.S. Sandia National Labs.

The 4-year $10 million research project will involve development of technology that will chemically store hydrogen in sodium aluminum hydrate - or sodium alanate for short.

In that process hydrogen would be pumped into an on-board vessel filled with sodium alanate. The tanks would store the hydrogen under low pressure until heat was applied to release the hydrogen.

The issues the team will deal with include storing enough hydrogen for driving range equivalent to today’s cars (that 300 miles or so) and quick refueling times. Current metal hydride storage containers need about 30 minutes to refill - far too long.

Visit Hyundai at http://worldwide.hyundai-motor.com/ , Enova Systems at http://www.enovasystems.com/ , UTC Fuel Cells at http://www.utcfuelcells.com/ , GM at http://www.gm.com/ , and Sandia National Labs at http://www.sandia.gov/ .