ECD Ovonics Hydrogen Prius
One of the original hydrogen-fueled Toyota Prius hybrids developed by ECD Ovonics to demonstrate its nickel-based solid state hydrogen storage. The current batch of Quantum-converted Priuses utilize 1.6 kilogram of 5,000 psi compressed hydrogen storage instead, giving a range of about 60 miles.

Santa Monica’s Hydrogen Priuses

Rick Sikes talks about the newest jewels in Santa Monica's alternative fuel fleet

By Bill Moore

Santa Monica, California is, by Rick Sikes' own definition, "an eclectic community" that is home to the super rich and the homeless. It comprises an area of eight square miles in west Los Angeles along the Pacific Coast, and it's his opinion that its citizens are some of the most environmentally and politically conscious people in the Los Angeles area.

"Part of it may be that you're right here on the water looking at the ocean and can see the effect. You can look inland and see the haze hovering over LA," he said.

Perhaps its chief attribute is its mandated to purchase all of the electric power for city-owned buildings from "green" generation sources: geothermal and solar power, exclusively.

The "green" mandate also extends to its 519 vehicle fleet, which is under Sikes' supervision. He pointed out, however, that this doesn't include the city's transit bus or police vehicles. The fleet Sike's oversees consists of water trucks, parking enforcement vehicles, maintenance staff pick-ups, garbage trucks, and cars for administrative personnel including some 27 Toyota RAV4 EVs and GEM neighborhood electric vehicles. Of the 519 vehicles in his charge, 264 are fueled by compressed natural gas, which he indicated is readily available at several locations in the city.

Of the remaining 255 vehicles, only 100 still burn conventional unleaded gasoline. The rest use "green' electricity, propane, B20 biodiesel and hydrogen; the latter in the city's five Toyota Prius conversions.

Santa Monica's 1994 "Sustainable City" program requires Sikes to acquire the least polluting vehicles available in each duty class, which means he generally ends up buying CNG vehicles given the dearth of pure electric vehicles at the moment.

"CNG vehicles are readily available for fleets. They operate like a regular gasoline vehicle; they have good power, good fuel economy, the admissions are super clean.

"I am charged with replacing vehicles with clean air-type vehicles with low emissions and sustainable fuel. So, if we were to get an electric vehicle, that would be the first choice, but after that comes the natural gas, because that's the cleanest sustainable fuel choice I have available."

The Hydrogen Option Santa Monica's newly acquired hydrogen-fueled Priuses are part of a regional AQMD (Air Quality Management District) program called the "Five Cities Project" that consists of 30 2004-2005 model year Priuses that have been retrofitted to burn hydrogen (H2) instead of gasoline in their internal combustion engines (ICE). There are no fuel cells installed in these vehicles. In essence, they are much like the city's CNG vehicles, though even cleaner since they burn only hydrogen and no carbon atoms.

Unlike fuel cells, H2ICE's do create NOx, a key component in smog formation, from atmospheric nitrogen in the combustion chamber. And like a fuel cell, water is also created, which poses a problem for the IC engine, as Sikes later observed.

To get a gasoline Prius to run on hydrogen is more involved than a compressed natural gas conversion. Where a CNG conversion might run $3000 to $5000 per unit, the Prius conversions cost $80,000 each -- funded entirely by the AQMD. This did not include the cars, whose Toyota fuel system warranty immediately lapsed, along with engine warranty, Sikes‘ suspects.

Quantum, the company who manufactures the super-strong carbon fiber hydrogen storage tanks, oversaw the conversion process that involved changing out the fuel system, replacing the injectors and fuel rails on the engine, adding a turbocharger and tweaking the Prius' computer control code. The 1.6 kilogram storage tank is located outside the passenger cabin, under the rear passenger seat. Sikes says that's roughly equivalent to one and a half gallons of gasoline. This gives his five Priuses, which are 2004 and 2005 models, ranges of between 60 and 80 miles (37.5 miles/kg to 50 m/kg).

In addition to Santa Monica, Burbank, Ontario, Riverside, and Santa Ana are also part of the AQMD program. Each has five cars; AQMD also operates five H2 Priuses.

"There are thirty of these vehicles, all operating in different types of environments. Ours is about an eight square mile city, so everything that we do is really close, a lot of stop-n-go… not much freeway driving. Compared to a Riverside or Ontario where they're going to have a longer range to drive in, they'll have different data to look at to see which operates best in."

Santa Monica got its first two vehicles in mid-May and its hydrogen filling station, which isn't currently available to the public, opened in mid-June. The city building inspector and two individuals in the water department were assigned the cars. The others are used for administrative tasks like attending meetings around the city. Sikes says the mileage varies from 30 miles a day to 30 miles in a week.

"They're not getting a lot of miles on them in Santa Monica."

Sikes candidly explained that there have been a couple small problems with the car, the most significant being the accumulation of water in the engine oil pan, water produced during combustion which vaporizes and seeps into the engine's lubrication system. This requires frequent oil changes. The other problem, which may be associated with the short distances the vehicles are driven, is their spark plugs are showing signs of rust.

Additionally, the cars are just a bit noisier than their gasoline counterparts because of the location of the exhaust closer to the firewall and the use of a turbocharger.

All 30 vehicles are operating under special AQMD exemptions and as such they cannot be sold to the public, unlike other city fleet vehicles that are usually sold at public auctions.

Sikes explained that there are only minor differences between driving a gasoline Prius and a converted hydrogen version. The person doing the refueling, for example, has to be certified. The hydrogen is produced by electrolysis at a rate of 12 kilograms a day and compressed to 5,000 psi. That's enough to refuel a number of additional vehicles each day besides the current five.

If a hydrogen infrastructure is to be created, clearly more vehicles are needed and H2ICEs like the Quantum-converted Priuses are one way to get there. They may not be as elegant a solution as a fuel cell electric car, and they clearly have their shortcomings, but comparatively speaking, the price is right and the technology is here.

One gets the sense, though that if given the choice between those H2 Priuses or battery equivalents like the RAV4 EV, Sikes would probably chose the latter, if only to put that ‘green' energy to more effective work for the citizens of Santa Monica.

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Times Article Viewed: 10874
Published: 08-Aug-2006


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