MIT primed to unleash solar revolution

[Eeyore]

Even if the process is 100% efficient,what happens next.
You can store the H2 either as liquid or compressed gas,

Which requires a lot of energy input.

but when you
convert the H2 back to electrtcity in a fuel cell, that process is at
best only 50% efficient.

So you're already < 50% efficient

A Hydrogen fuel cell producesa lot of heat in the process of making
electricity.
You can see this is the steam that comes out of them as water vapour.

And their lifetime is not that long AIUI and they use expensive materials
like platinum IIRC.

No large scale energy storage system can afford to lose 50% of the
stored energy.
Even pumped hydro is better than 50%.

Absolutely.

Graham

 

[J. Clarke]

Which requires a lot of energy input.

Calculate this as a percentage of the energy to be derived from
reacting the hydrogen with oxygen.

So you're already < 50% efficient

Only if you accept his premise.

And their lifetime is not that long AIUI and they use expensive
materials like platinum IIRC.

The same is true of the emission control system in every car sold in
the United States in the past 30 years or so.

Absolutely.

So you're saying that no energy storage system is practical. Then I
guess when the oil runs out we have to go back to horse-drawn
transport.

 

[Eeyore]

Calculate this as a percentage of the energy to be derived from
reacting the hydrogen with oxygen.

That's one way to do it.

Only if you accept his premise.

The current hydrogen fuel cells I'm aware of are typically around 50%
efficient. Google for yourself if you doubt it.

The same is true of the emission control system in every car sold in
the United States in the past 30 years or so.

Also true. But I gather H2 fuel cells have rather shorter lifetimes and
are rather bigger.

So you're saying that no energy storage system is practical. Then I
guess when the oil runs out we have to go back to horse-drawn
transport.

Let's say finding an effective, efficient, practical and affordable energy
storage system is going to be one hell of a task.

Graham

 

[Eeyore]

Where have they made that claim?

In their publicity IIRC. At least that is their target.

Graham

 

[J. Clarke]

That's one way to do it.

You know another?

The current hydrogen fuel cells I'm aware of are typically around
50%
efficient. Google for yourself if you doubt it.

Perhaps if you followed your own advice you would be aware that that
is not the case.

Also true. But I gather H2 fuel cells have rather shorter lifetimes
and are rather bigger.

The emission control system's catalyst is good for 50,000 miles.
Honda will lease you a fuel cell car now, today, that should do at
least as well.

Let's say finding an effective, efficient, practical and affordable
energy storage system is going to be one hell of a task.

Hydrogen works, now, today, for energy storage. The difficulty is the
production infrastructure.

 

[Mauried]

That's one way to do it.



The current hydrogen fuel cells I'm aware of are typically around 50%
efficient. Google for yourself if you doubt it.



Also true. But I gather H2 fuel cells have rather shorter lifetimes and
are rather bigger.



Let's say finding an effective, efficient, practical and affordable energy
storage system is going to be one hell of a task.

Graham

Far better to simply use energy production schemes that dont need any
storage in the first place , ie that produce energy all the time.
Nuclear power plants dont need storage.
Geo thermal power plants dont need storage.

 

[J. Clarke]

Far better to simply use energy production schemes that dont need
any
storage in the first place , ie that produce energy all the time.
Nuclear power plants dont need storage.
Geo thermal power plants dont need storage.

So how do you run a car on geothermal power? Or nuclear for that
matter?

 

[Eeyore]

Hydrogen works, now, today, for energy storage. The difficulty is the
production infrastructure.

Hydrogen is bedevilled with huge problems for storage. Please don't tell
me you're not aware of them. The list is as long as my arm.

Graham

 

[Eeyore]

Far better to simply use energy production schemes that dont need any
storage in the first place , ie that produce energy all the time.
Nuclear power plants dont need storage.
Geo thermal power plants dont need storage.

Agreed. And we know how to build them TODAY.

Graham

 

[Eeyore]

So how do you run a car on geothermal power?

Steam ? ;~)

Or nuclear for that matter?

PHEVs of course.

Graham

 

[J. Clarke]

Steam ?

How do you get the steam to the car? Tow a thousand miles of pipe?

PHEVs of course.

Plug in hybrids still have internal combustion engines. What do you
run those engines on?

 

[J. Clarke]

Hydrogen is bedevilled with huge problems for storage. Please don't
tell me you're not aware of them. The list is as long as my arm.

Tell it to Honda.

 

[Eeyore]

How do you get the steam to the car? Tow a thousand miles of pipe?

It's what they calla a tongue in cheek comment. Actually purely steam
powered locomotives have been used in mines and the like.

Plug in hybrids still have internal combustion engines. What do you
run those engines on?

Fot the first 40-50 miles they run on battery power. The ICE is only
there to give them extended range.

Graham

 

[Eeyore]

Tell it to Honda.

Containing hydrogen in a small vehicle is no problem. Aside from fuel
tank explosions.

Now go nationwide. I bet you haven't a clue what the problems are.

Graham

 

[J. Clarke]

Containing hydrogen in a small vehicle is no problem. Aside from
fuel
tank explosions.

When there's a fuel tank explosion in a hydrogen fueled vehicle that
is worse than a fuel tank explosion in a gasoline fueled vehicle of
similar size get back to us.

Now go nationwide. I bet you haven't a clue what the problems are.

So tell us. But give me a minute to make some popcorn.

 

[J. Clarke]

It's what they calla a tongue in cheek comment. Actually purely
steam
powered locomotives have been used in mines and the like.

How did the steam get there?

Fot the first 40-50 miles they run on battery power. The ICE is only
there to give them extended range.

And it's better to use an internal combustion engine than a fuel cell
because?

 

[Eeyore]

How did the steam get there?

From heat.

And it's better to use an internal combustion engine than a fuel cell
because?

Because overall (taking everything into acccount) it's VASTLY more
efficient. Especially with diesels @ 40% thermal efficeincy.

Large bulk carrier ships have diiesel engines that are around or better
50% thermal efficiency.

Graham

 

[J. Clarke]

From heat.

And how did the heat get there?

Because overall (taking everything into acccount) it's VASTLY more
efficient. Especially with diesels @ 40% thermal efficeincy.

Large bulk carrier ships have diiesel engines that are around or
better 50% thermal efficiency.

Uh huh. Stationary power plants are doing well to hit 50 percent.

And how are either of these better than fuel cells at 80 percent?

 

[Eeyore]

When there's a fuel tank explosion in a hydrogen fueled vehicle that
is worse than a fuel tank explosion in a gasoline fueled vehicle of
similar size get back to us.

Suggest you take a peek at what an oxy tank explosion recently did to
Qantas QF30.

Graham

 

[Eeyore]

Uh huh. Stationary power plants are doing well to hit 50 percent.
http://en.wikipedia.org/wiki/Wärtsilä-Sulzer_RTA96-C
http://people.bath.ac.uk/ccsshb/12cyl/

And how are either of these better than fuel cells at 80 percent?

You forgot the losses getting the fuel to the cell.

Graham