Re: [All-E] Group keeps hope alive for battery-powered personal vehicles
- hey guys thanks for the feedback...
> > > I have heard that in terms of energy efficiencyFuel cells efficiency ranges dramatically. PEMs have
> > > battery powered cars are be more efficient than
> fuel cells. Does anyone know if this is true?
> > >
> > Yes. Electrical-to-Electrical efficiency of
> hydrogen fuel cells is
> > about 50%.
> Hrrrm. So, if I expend a kilowatt-hour of
> electricity using
> elctrolysis to make hydrogen, then pipe that
> hydrogen directly into a
> fuel cell, I can only expect 500 watt-hours of
> elctricity back out?
> I thought it was a bit higher than that, honestly.
> Do you happen to
> have a link to s source for this?
more direct efficiency because they have less heat
loss, while solid oxides and molten carbonates have
lower electrical efficiencies by higher heat loss but
they can be used in cogeneration.
> > When you consider compressing the hydrogen,I was not sure about was the 90 percent efficency of
> carrying the
> > extra weight of the storage container, and
> distilling the water
> > electrolysis, it's even lower.
The relevance of fuel cells relates to how they are
developed and the number of energy conversions needed
to keep these systems running. Looking back at the
research about Hydrogen I am little disappointed, I
think it is quite reductionistic focusing PEM fuel
cells with external reformers and natural gas and
water hydrolysis to provide hydrogen for these
systems. However i still think fuel cell technologies
are promising but I am specifically talking about
stationary applications like the ones being developed
by Fuel Cell Energy that can run on biogas, coal gas,
natural gas, propane and even desiel with minimal
emissions. The key difference is that these larger
fuel cells rely on an internal reforming process that
is integrated with the cogeneration process. The gases
used for cogeneration also are used to ensure the
complete combustion of hydrocarbons, therefore
emissions from such facilities are nearly zero.
It sounds like the battery car program is being
ditched and all our energy is now being focused on
fuel cell cars when eletrical technologies can with
the proper funding probably achieve the same goals
(zero emission cars) at a considerably higher rate of
efficiency. And people wonder why alternative energy
does not live up to its potential?
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- I agree that it will be necessary for fuel cell vehicles to be equiped with on-board reforming to make them an efficient system. Ballard seems to be on the forfront of mass producing fuel cells specifically designed for vehicle mass production, but they are not going in the direction of on-board reforming. It's too bad. I think it puts us in the position of NEEDING mass distribution of hydrogen, which means large production facilities to reform fossil fuels instead of water and the big question; Where do they get the electricity. British Petroleum and RoyalDutch/Shell are europes biggest promoter of this as well as some of the american oil companies, i think because it sustain the power structure that DG and onboard reforming threaten. One of the questions I have is why are BP and Shell so interested in renewables. It doesn't make any sense. The other question I have is how can the DOE possibly think that their road map if they are going to stay geared toward the use of fossil fuel-stock and electricity from the national grid. It will never make it affordable, nor will it guarantee a permanent source of fuel-stock. It's like using natural gas to power the nation and then having to import it due to dwindling supplies. Oil cannot last forever. Even if hydrogen or fuel cells aren't the complete answer they do have some benefits, if they are used properly; ie. water reforming and renewable source electricity. The main benefit is that it may be able to shore the gap between the 2-4% increase in demand and the sortfalls in new energy production allowing deregulation to progress under a market system instead of a monopoly that will never be able to think environmentally. Some of these, if not all are opinions, but the questions are real curiosities.Light..www.hydrogenSun.com
Michael DeWolf <m_dewolf@...> wrote:
michael light <hydrogensun@y...> wrote:
> During this phase, TMI demonstrated passive reversible cells and
stacks that met many of the performance targets including reversible
efficiency and life. Several conditions were evaluated to understand
the sensitivity of performance on operating variables such as
temperature and current density. The highest reversible efficiency
(DCVolts_Out / DCVoltage_In) measured was 90.8% at 925 �C and 50 mA/cm.
I did some research, and the TMI fuel cell has a 90.8% efficiency
*when the heat from the fuel cell is used to make the electrolyser
more efficient*. Novel, for sure.
For transportation, however, this would not be possible.
I have heard, though, that Solid Oxide fuel cells are more efficient
than PEM fuel cells. Maybe hydrogen generation is another use for
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