Hydrogen vs. Battery

[richkae]

So true!


Meanwhile gasoline kills so many people that it doesn't even make the national news. There are many, many reasons why fuel cells are a bad idea, including, but not limited to the short life of fuel cells, the inefficiency of H2 production, and the fact that it's cheaper to burn H2 in an ICE than in a million-dollar fuel cell. But as far as safety, I'm inclined to think that H2 is probably safer than gasoline. It requires just the right fuel:air mixture to burn, and when it leaks it goes up and away, unlike gasoline, which sits on the ground and burns until it's gone, or soaks into your clothing and burns you to a crisp.

Unfortunately hydrogen is stored under such pressure that the container itself is a bomb - regardless of whether the hydrogen ignites.

 

[Doug_G]

But as far as safety, I'm inclined to think that H2 is probably safer than gasoline. It requires just the right fuel:air mixture to burn, and when it leaks it goes up and away, unlike gasoline, which sits on the ground and burns until it's gone, or soaks into your clothing and burns you to a crisp.

Hydrogen is much more of an explosion danger than gasoline - spectacularly so. Gasoline vapors are explosive in 1.4% to 7.6% concentrations, while hydrogen is explosive in concentrations of 4–74%. In other words, almost any concentration of hydrogen is explosive. Hydrogen is essentially the most dangerous gas in existence in terms of how easy it is to trigger an explosion.

 

[dpeilow]

Bought and paid for: Chu sees benefits of hydrogen fuel cells | Aiken Standard

 

[doug]

Bought and paid for: Chu sees benefits of hydrogen fuel cells | Aiken Standard

They're just trying to boost their industry. Chu didn't actually say much, but they're making a big deal about the little he did say. So far he hasn't let them have much cash.

 

[dpeilow]

It's an election year.

 

[doug]

Hydrogen Fuel-Cell Cars Still Important, Automakers Say

In Germany, Federal and state funding to build a network of hundreds of hydrogen fueling stations now totals in the hundreds of millions of dollars.

But the current political climate makes that kind of funding seems highly unlikely in the U.S. And Jerram notes that Toyota, Honda, and Daimler representatives at the conference "were unanimous that they should not have to foot the bill for infrastructure build-out."

 

[dpeilow]

OK then - let the private sector build out a hydrogen network...

 

[rabar10]

Elon's take on the Hydrogen vs. Battery discussion came up in the Q&A of the recent Fireside Chat with Elon Musk.

The question is asked at 0:53:47 in the YouTube video of the event. Here's a quick transcription:

Honda, Mercedes have both said that they clearly feel that hydrogen fuel cells are the the future [Elon scoffs], but I believe strongly in batteries (I know!). Why do you think that they are so committed to hydrogen as the next step, whereas batteries, I really feel like we could make this happen?

I don't really know, because the math is so super-obviously in favor of batteries, that it's like staring facts in the face and saying they're not true.

If you take the best-case scenario for a fuel cell -- assume it's fully optimized, so you envelope it from a physics standpoint, and give it the best-case situation -- how does that compare to state-of-the-art lithium-ion, or current lithium-ion in production? It loses.

So it's like, success is not one of the possible outcomes, why embark upon that? It's crazy.

I think they felt for a long time that there was this need to be doing -something-, and since fuel cells were 10 years in the future and always would be, then they could always say that they were working on fuel cells, and that would satisfy people.

Tesla called it "fool sells".

 

[brianman]

Both this and the Fisker design comment -- I'd love to hear an honest attempt at a rebuttal.

 

[W.Petefish]

"Fool Cells"

HA HA HA HA HA HA!!!!:biggrin:

 

[jerry33]

Even though fool cells is hardly original with Elon, it's still a good description.

 

[brianman]

IIRC, he said something like "around Tesla we call them" not "I started ..."

 

[dpeilow]

The hydrogen fool sell is a phrase that has been used about the hook-line-and-sinker swallowing by politicians.

 

[dpeilow]

Speaking of which...

Technology Strategy Board Grant Award | ITM Power

In my back yard too.


ITM Power blocked me on twitter after I replied to that.

 

[brianman]

ITM Power blocked me on twitter after I replied to that.

Heh. What did you say?

 

[ItsNotAboutTheMoney]

Both this and the Fisker design comment -- I'd love to hear an honest attempt at a rebuttal.

Let me give it a shot with HFC.

Besides the cost, the main limitations of batteries are low energy density and slow refueling. HFCs are better at both. The TtW efficiency of HFC is also higher than NG to the extent that it can be more efficient to use NG-sourced hydrogen than to run a vehicle on NG. In addition, while currently inefficient, hydrogen can be generated using renewable energy.

So, unless we want to cross our fingers and hope that battery technology improves so dramatically that it can meet all transportation needs economically we should continue aggressively to pursue other technologies.

(Just don't let them kid us that they're anywhere near market-ready.)

 

[Adm]

Apart from the efficiency issue, there is the matter of cost. ITM sells a 100kg/24h unit for £ 713k/€900k. That kind of money is enough to buy and install 18 CHAdeMO 50kW chargers.

 

[stopcrazypp]

Let me give it a shot with HFC.

Besides the cost, the main limitations of batteries are low energy density and slow refueling. HFCs are better at both. The TtW efficiency of HFC is also higher than NG to the extent that it can be more efficient to use NG-sourced hydrogen than to run a vehicle on NG. In addition, while currently inefficient, hydrogen can be generated using renewable energy.

So, unless we want to cross our fingers and hope that battery technology improves so dramatically that it can meet all transportation needs economically we should continue aggressively to pursue other technologies.

(Just don't let them kid us that they're anywhere near market-ready.)

Volumetrically, hydrogen is not much better than batteries in terms of density. The F-cell only goes 190 miles EPA on a 350 bar tank (most common pressure). At a higher 700 bar pressure the range is 70% more at 323 miles. So in terms of passenger vehicles it's not going to do much better and batteries have a potential of overtaking them (because there is still lots of room for density improvement, you can't really improve hydrogen density without raising the pressure).

Where they win big is when weight matters (like long haul trucks). There it makes more sense, esp. for fleet usage with a central refueling location.

And I think given battery swapping (which is faster than refueling) the refueling speed argument doesn't apply anymore. Battery swapping has its own infrastructure issues, but so does hydrogen. Battery swap stations are being built all over Israel and Denmark by Better Place. Say what you will about their subscription model, but the swapping does work and you get in and out in 5 minutes flat (this includes the driving in and out, not just the swapping processing).

 

[ItsNotAboutTheMoney]

And I think given battery swapping (which is faster than refueling) the refueling speed argument doesn't apply anymore. Battery swapping has its own infrastructure issues, but so does hydrogen. Battery swap stations are being built all over Israel and Denmark by Better Place. Say what you will about their subscription model, but the swapping does work and you get in and out in 5 minutes flat (this includes the driving in and out, not just the swapping processing).

Q What's are the key problems with batteries?
A They are expensive and slow to charge.

Q What do you need for large-scale battery swapping?
A A large number of charged batteries at a large number of swap stations.

Availability supporting variable demand requires redundancy (see electrical generation), and for batteries it's redundancy of the most expensive part in the car. In other words, effective battery swapping means that there must either be more than 1 battery for each car and either significantly more than 1 or restricted travel at periods of peak demand. On top of that, the swap stations are effectively swapping a low-density fuel tank, so require a larger storage space.

There's a lot of redundancy in liquid/gas refueling infrastructure, but it's cheaper redundancy of a denser consumable.

 

[dpeilow]

Heh. What did you say?

I replied with the http://efcf.com/reports/E21.pdf link and copied a few others involved in their project on the tweet.