CAFE Electric Aircraft Symposium Set For May 1

On Thu, 14 May 2015 14:14:43 -0400, Vaughn wrote:

On 5/14/2015 1:49 PM, Larry Dighera wrote:
It takes energy to make the hydrogen because it doesn't exist
in it's free state naturally on Earth. Currently, most hydrogen
is produced from natural gas, with CO2 as a byproduct.

It takes energy to compress it, or liquify it.

It takes energy to refridgerate it to such low temperatures.
and to keep it there.

Photovoltaic powered electrolysis of H2O would be my choice to produce
hydrogen. It might even power the compressor and condenser to liquefy it also.
Other than the energy used to make the solar cells, there is no energy cost and
no byproducts. Making this practical will take some ingenuity, but
theoretically, I'd suppose it is possible.



Sorry, but there is no free energy,


Agreed. I don't think that is at issue here.


and there is no totally clean energy, not even solar.


Aside from the waste products associated with the production of solar cells,
I'm not aware of any polluting products emitted by photovoltaic electricity
generation.


At present, there isn't enough solar energy to go around.


Mmmm... When it isn't cloudy, there's about 1KW per square meter. It would
seem, that if you've got the land area, there's more than enough solar energy
"to go around", at lease here in southern California. What makes you say that?
Are you saying, that there currently hasn't been enough solar energy generating
stations built to supply the entire nation/world?


There isn't likely to EVER be enough solar energy to go around,


Are you able to cite a credible source that supports that assertion? What
leads you to believe that?


that's also true of wind and hydro power.


Are you intimating that petroleum based electric generation is the sole
technology that is able to supply the world's needs?

Again, are you able to cite a credible source that supports your an opinion?


More importantly, if we divert solar energy from the grid to make
hydrogen, then we must make up the difference from somewhere else, which
means burning more fuel. So there is no advantage to diverting "clean"
energy towards something like producing hydrogen, whilst we are burning
coal (or whatever) to make grid power.


I wasn't suggesting that grid electricity be used to electrolyze H2O. I was
thinking that solar cells on the roof of a home might be employed electrolyze
water to produce H2 and O2 that would be stored, and used to produce
electricity at a later date.


Energy is energy! Wasting energy is always a dirty thing to do, even if
it's solar.


So, you're saying, that when the Sun is shining on bear earth, we are doing a
"dirty thing" by not capturing the solar energy? Or am I missing your point?


And the hydrogen energy cycle is inherently wasteful.


It is true that electrolysis of H2O is not too efficient yet. Until recently
fuel-cell technology hasn't been too efficient either (about 30%). but when I
visited the 2014 Consumer Electronics Show in Las Vegas, an automotive engineer
assured me that they had increased fuel-cell efficiency to 60%, so presumably
the art is making strides toward increasing efficiency. And, if/when H2 power
becomes more mainstream, I would expect the resulting increase in R&D funding
to continue that trend.

How efficient is distilling petroleum into gasoline/kerosene? How efficient
are internal combustion engines piston and turbine?

I appreciate your interest in the subject, but I'm at a loss to understand your
points. And without any supporting research studies or hard data, I'm unable
to put much credence in your unsupported assertions.

Please tell me more about what you KNOW about this subject.