Will personal vehicles of the bright green future be battery-electric or hydrogen fuel cell based? The most reasonable answer is probably "both," with battery and fuel cell vehicle power storage co-existing like gasoline and diesel today, used in ways which take advantage of unique strengths. Yesterday's fast-recharge battery news from Toshiba certainly gave new vigor to the idea of usable battery-powered cars, potentially solving the "it takes how long to refill?!?" problem. But while hydrogen fuel cells have their detractors (some of whom post in the comments here frequently), the technology has been improving quite steadily.
Yesterday, Ballard Fuel Cells -- probably the best known dedicated fuel cell company around -- announced its technology "road map" for the next five years, staking its future on its ability to meet a series of key requirements by 2010.
5,000 hours of lifetime; freeze start capability to -30 degrees C; volumetric power density of 2,500 Watts net/liter; and fuel cell stack cost of US $30/kW net at a volume of 500,000 units
To put those into perspective, the projected 2005 values for each is:
~2200 hours; freeze start possible to -20 degrees C, taking ~100 seconds; power density of approximately 1,400 Watts net/liter; and stack cost of about US $85/kW net at volume.
Not covered in the Ballard road map are issues of hydrogen production, distribution, storage in the vehicle and "pump time," all of which must be figured out in order for the hydrogen future to come about. Again, these are not impossible challenges. From a WorldChanging perspective, the one requiring the greatest effort will be production, if only because the less clean sources of hydrogen (that is, ones still relying on fossil fuels and producing carbon dioxide as an emission) are likely to be the cheapest in the short term. A hydrogen economy tied to non-renewable, extractive feedstocks -- e.g., coal and natural gas, the two most often cited -- is a bright green illusion at best.
Once again, what appears to be an issue of technology turns out to be instead a question of infrastructure.
IIRC, gas-powered internal combustion engines have an efficiency of about 20-25% (the rest of the energy contained in the gas is lost, mostly as heat).
Fuel Cells have an efficiency level that is much higher (around 85-90%, IIRC). So unless the conversion from fossil fuel -> hydrogen is very wasteful, the overall efficiency of transportation would be quite a bit higher even if the hydrogen used is not clean, right?
Am I missing something?
Not saying that we should based hydrogen production on fossil fuel, but that anything that helps get the infrastructure built and that eases the transition is good.
Fuel cell efficiencies are all over the map, depending on the chemistry. Phosphoric acid is down around 40%, molten carbonate and solid-oxide are 55-60%, and PEM hits something like 80%.
I would love to be able to buy a 10 kW fuel-cell stack for $850, as long as I could get a natural gas reformer for it for no more than that. That sucker would power my house without breaking a sweat, and the waste heat from the reformer would provide all the hot water I'd want.
I've been following some of the "well to wheels" and "powerplant to wheels" comparisons. Basically people have been figuring the heat to tail energy efficiency of various technologies, as a way to compare what would otherwise be apples and oranges.
This four page pdf from the EUROPEAN FUEL CELL FORUM has a lot of good comparisons on the last couple pages:
meant to say "head to tail" ,,, and here are a couple more:
both found at:
Frankly, shifting from internal combustion to the next generation is something best done in phases. If Ballard can put out a fuel cell powerplant in 2010 that costs about the same as internal combustion, lasts about as long, and is no worse for the environment than prior, I say it's a distinct improvement. Burning fossil fuels will always be dirty. Shifting to engines that can be clean is a major step to a world where engines actually will be clean.
I think that you're not going to get rid of oil product reformation ever but the percent derived from that method can be driven down over time. That's never going to matter as long as the fuel cell stacks aren't ready for prime time.
Odograph, you hit the nail on the head. If you take a total "well-to-wheel" + "wheel-to-tailpipe" approach, hydrogen loses the battle qua efficiency and energy consumption against diesel-hybrids, and it loses the battle against energy consumption and total life-cycle GHG emissions with biodiesel-hybrids.
Biodiesel-hybrids are the big champions and may well await a bright future.
Hydrogen's "well-to-wheel" efficiency is 22% at best.
"Hydrogen's "well-to-wheel" efficiency is 22% at best."
Where can I find the physics behind this claim? On first impression this seems a bit of a conservative estimate, i'd like to know what I'm missing here...
Rikkert, there are lots of numbers, almost too many numbers, but for what it's worth here are the ones I settled with:
They come from a huge PDF you can read for greater detail.
Well an important thing to remember when talking about any new tech is who is behind the money and why?
The fact is hydrogen is being pushed 100x as hard as anything else because of who is behind it and why they are.
Big oil is behind it because they know they can make money off it when they transition to it.
The military is behind it because its one hell of alot better to gen your fuel in place then it is to ship it for 400 bucks a gallon;/ Also since they want to switch to high powered laser weaponry systems a fuel cell is wonderful.. a fuel cell stack capable of a megawatt is thier dream.
Car makers are behind it because it removes all need for polution controls and it removes them from the environmental issue and moves that to who generated the hydrogen. It also will allow them to make cars very different and far more futuristic then current methods. Finaly a fuel cell is a perfect combo to todays cars needing more and more electricity anyway...
A big group og big forces want hydrogen for very sound reasons so hydrogen is a given fuel source.
Too bad it isn't a closed command-and-control economy, eh?
(we get danish windmills and japanese cars, sometimes just when needed)
Well in general if you wana see where things will go you follow the money. The money is behind hydrogen in a big way. Mind you oil companies also seem to be behind biodeasel and coal to liquids as well so they arnt 100% behind hydrogen;/ But many others seem to be.