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UTC Power Attains 5,000-Hour Durability Milestone With Transit Bus Fuel Cell System

A PureMotion system in a bus. Source: UTC. Click to enlarge.

UTC Power, a United Technologies Corp. company, announced that one of its latest generation PureMotion Model 120 fuel cell powerplants for hybrid-electric transit buses has surpassed 5,000 operating hours in real-world service with its original cell stacks and no cell replacements.

This powerplant is aboard an Alameda-Contra Costa Transit District (AC Transit) bus operating in the Greater Oakland, California area.

Stack durability matters. It is recognized by the industry as a key challenge in commercializing fuel cell vehicles worldwide. The last time we serviced the stacks in that bus, all of the candidates for President still had nine months of campaigning to do. UTC Power has significantly improved fuel cell stack durability and we’re confident that our progress will continue.

—UTC Power Vice President-Transportation Ken Stewart

The PureMotion 120 system delivers 120 kW net power at a voltage range of 290 to 580 VDC. Efficiency @120 kW is more than 46%. The system is liquid cooled, and has an operating temperature range of -10 °C to 49 °C (14 °F to 120 °F).

Three of AC Transit’s buses are equipped with UTC Power fuel cell systems and have now traveled more than 213,000 miles, with an average fuel economy that is 65% better than the control fleet of diesel buses running the same routes and duty cycles.

Fuel cell buses have a significant effect on reducing greenhouse gases, ranging from a 43% reduction over diesel buses if hydrogen is supplied from the reformation of natural gas, up to a 100% reduction when hydrogen is generated from on-site renewable sources like solar and wind power.

A 2009 report on worldwide hydrogen bus demonstration programs completed on behalf of the US Department of Transportation Federal Transit Administration noted that zero-emission buses performed well across a wide range of operating conditions, including hilly and flat terrain, hot and cold temperatures and high and low-speed duty cycles. There were no major safety issues over millions of miles of vehicle service, and most participants found that drivers preferred fuel cell buses to compressed natural gas or diesel, noting their smooth ride, ease of operation, strong acceleration and ability to maneuver well in traffic. (Earlier post.)

UTC Power has provided fuel cell power plants for fleet transportation since 1998 and its fuel cells have powered buses in the United States, Spain, Italy and Belgium. The company’s latest-generation proton exchange membrane (PEM) fuel cell system has delivered more than 350,000 miles of commercial service for city transit bus fleets.



UTC had the ONSI division that made MCFCs that went into bank and hospitals for UPS. They would take in natural gas and put out electricity and heat for a very good CHP efficiency.

It is good to see them in this business. They are an industrial grade company with credibility. You can count on their reliability figures, their company reputation is at stake.


This good news is limited if the FC costs a $million.


Is thos 5000 hours on the same fuel cell or a total of 5000 hours on 3 ++ cells?


"more than 213,000 miles"

So each of 3 buses averaged more than 70,000 miles. At 14 mph that would make around 5000 hours on each bus. This is just guess work.


Its 5k on one fuel cell stack.


Ok, that's great. Now how much does it cost? I know that NYC paid an extra $150K for their new Orion hybrid-diesel buses compared to a regular diesel and they decided it was cost effective over the life of the bus after considering the reduced fuel cost per mile and maintenance cost per mile (mostly driven by brake wear and tear that is greatly reduced).

So, what is the story for the fuel cell cost???

aussie paul

First gen bus $3m, second gen bus $2m and volume production $1m to $1.2m. These are hybrid buses also. Second gen full life cycle costs are close to diesel.

Henry Gibson

Cells, lies and DVDs.

The fuel cells are very expensive. The process of compressing hydrogen is very expensive. There will be no cost of operation advantages to fuel cell buses for a long time if ever.

Diesel type engines can get the same efficiency without the losses of converting natural gas to hydrogen or the compression losses of hydrogen or the losses of carrying heavy hydrogen tanks on the buses. Fuel efficiency of bus operation is not a big concern in operating a bus once any type of hybrid operation is used and perhaps even without using it.

Electric buses using the new GE batteries will use solar power and wind power or any power with double the efficiency. There is no reason why transit busses cannot have temporary charging connections, and long distance busses can be super efficient diesel electric hybrids. Actually Capstone turbine generators are efficient enough and have almost no maintenance costs.

When nuclear energy (3,000,000 pounds of coal for 1 pound plutonium) is by France and others in the future to produce hydrogen, the hydrogen can be combined with CO2 captured from fermenting wines even to make liquid fuels so that even antique cars can operate on zero net carbon.

MES-DEA ZEBRA batteries and the similar GE batteries will be more reliable, less energy and cheaper to operate, but as always, there must be the, seldom used, electrical equivalent of a 5kw diesel or gasoline fuel powered generator for unexpected long distance travel remote from charging opportunities. Propane and autogas are options. ..HG..

Henry Gibson

Also the cost of the fuel cell could be reduced to about half or less if a much smaller stack were used with ZEBRA batteries in a hybrid configuration with charging equipment at stops that can have stationary Firefly batteries provide high rate charging. ..HG..


"These buses use ZEBRA NaNiCl batteries that have performed below expectation, with deployment sites reporting frequent battery system troubles. Several participants felt that battery technology is not advancing."


Its important to note this stack isnt based on newer fuel cell stacks its using the same tech as the OLD gen fuel cells.

The next gen of the system should if it follows the other fuel cell stacks out there be less then half the size and weight get 20-25% better milage and run for 3-4x as long... oh and all while costing far far less,


5000 hours translates to about 150k miles which is pretty good in terms of durability, esp for a fuel cell.

Buses cost more so they can more readily absorb the extra costs of a fuel cell.

I ride AC Transit regularly so I probably have seen this bus around a couple of times already, though I haven't ridden in one before.


Actually scratch that. I was using the estimate for passenger cars: 30mph * 5000 hrs = 150k miles.

An typical AC Transit bus averages 11 mph so: 5000 * 11 = 55k miles. The 2006-2007 evaluation of the AC Transit fuel cell buses operating for 5,765 hours corresponded to 62,191 miles.

I wonder how this operating life translates to passenger cars which have a higher average speed and different power demands. These buses seem to be hybrid buses and has a fairly large battery pack in it (only a few kwh less than the one on the Tesla Roadster), which probably aids the fuel cell's operating life.


The current system is over 5k hours and 71000 miles and has yet to be replaced so we dont actauly know how far it will go.

They say they plan for 10k hour warrenties on this system and 30k on the next with a third system down the road getting 60k hour lifecycles... that would be about 800k miles.

Id expect the 30k system to pop up somwhere near 2015-2018. This system is about 1 by 1.1 by 1.4 meters and 900 kg id expect the next one will be about half that and the one after about 300-400 kg.


Would combo ultracaps + fuel cell work better than batteries + fuel cells for stop start usage such as city buses?

Ultracaps would certain last as long as second and third generation fuel cells while batteries may not.


Both the engine and fuel cell run on hydrogen. I would rather see them both run on CNG with a reformer for the fuel cell. There are already CNG diesel buses, this would be a hybrid CNG with a large fuel cell APU that runs continuously.

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