Hydrogen vs. Battery

[SageBrush]

Yeah, impressive that part of the "energy density" is not contained in the paste

I don't see that as a problem in itself.

 

[mspohr]

More hype: Powerpaste Stores Hydrogen Energy | State of Clean Hydrogen



Sounds good, except for this part:


Yeah, impressive that part of the "energy density" is not contained in the paste

Looks like another desperate attempt to make hydrogen relevant. No word on the efficiency of the process.

 

[JRP3]

I don't see that as a problem in itself.

You need to carry around water which needs to be factored into the "energy density".

 

[SageBrush]

You need to carry around water which needs to be factored into the "energy density".

Sure, but the Gibbs free energy of water is 237 kJ/mole

Some arithmetic:
One liter of water at STP is 1000 grams
One mole of H2O is 18 grams
So about 5.5 moles of H2O per liter
A liter of water then has 18*237 KJ = 4,266 kJ of energy = 1.18 kWh

100 Kg of water is 118 kWh

As I said, that is not an obvious show stopper to me.
I have no opinion about the rest of the idea

 

[SageBrush]

Some arithmetic:
One liter of water at STP is 1000 grams
One mole of H2O is 18 grams
So about 5.5 moles of H2O per liter

Oops, sorry -- Arithmetic error above. Should be
55.5 moles of H2O per liter
So 55.5*237 KJ = 3.66 kWh per liter

 

[Electroman]

which heats hydrogen with magnesium and stabilizers so the hydrogen can be stored in cartridges even at room temperature

Step 1. You need to extract H2 from some source. We all know if you want to get it cheap it has to be from fossil fuel extraction as a byproduct, or you expend a lot of energy to extract H2 from H2O

The paste is made by combining hydrogen and magnesium into magnesium hydride, then adding an organic compound called an ester

Step 2: Instead of compressing the hydrogen to high density (or liquefying), which in itself takes a ton of energy to do that, instead you spend the same amount of energy to heat up a concoction of slurries to get to a paste, where H2 is embedded in it.

So far in these two steps you haven't achieved much, except you have a H2-Mg slurry instead of pure compressed H2, by spending the same amount of energy.

But the next step is interesting.

where it reacts with water to release hydrogen at a dynamically controlled rate,

Now the extraction seems to have a lot more going here, because you get H2 from two sources - the slurry H2-Mg paste and H2O. So I presume you get a lot more H2 available at the consumption end, somewhat comparable to the same volumetric & gravimetric energy densities of gasoline. Now this is a BIG win. Presumably you can go twice or three times the distance of of BEV with same weight and volume. I am basing this conservatively on the 10 times energy density value in that article.

Let us see what problems are solved and not solved:

Not solved:
- The energy/environment cost to produce H2. There is no change on this step.
- Cost to make H2 energy dense. You still need a ton of heat to make that happen

Solved or can be solved:
- Energy density: Producing enough H2 in a small space of a car's hood (or Truck) to propel it to 700+ miles. This is a BIG WIN. You now have something other than Gasoline that has comparable energy density.
- Refueling time: Can be solved. Hopefully can be made as quick as gasoline
- Expensive fueling infrastructure: Can be Solved. You don't need all those expensive H2 fueling stations.

 

[SageBrush]

There are too many issues with hydrogen to count, but most fundamentally its efficiency pathway sucks.

I was reading this AM about a new start-up in Israel called chakratec that is trying to commercialize the fly-wheel as an intermediate for DC fast charging where the grid cannot support high power. It obviously also has application for demand charges and time shifting.

I was unable to find any pricing, but at least the efficiency is highly attractive and materials science can be applied to any flywheel issues. I love new applications of time tested innovations. And it speaks to my deep seated hunch that magnetism is the key to solving a plethora of new energy obstacles.

 

[ItsNotAboutTheMoney]

Step 1. You need to extract H2 from some source. We all know if you want to get it cheap it has to be from fossil fuel extraction as a byproduct, or you expend a lot of energy to extract H2 from H2O

It's not the electrolysis energy that's a problem, it's the electrolyzers.

 

[brucet999]

More hype: Powerpaste Stores Hydrogen Energy | State of Clean Hydrogen



Sounds good, except for this part:


Yeah, impressive that part of the "energy density" is not contained in the paste

I wonder how many miles per gallon - of water - it gets?

 

[Guy V]

You need to carry around water which needs to be factored into the "energy density".

The output of the fuel cell is electricity and water.

 

[eevee-fan]

I wonder how many miles per gallon - of water - it gets?

I'd rather run on bottled water. LOL

Study: Most Bottled Water Comes from Tap, More Expensive Than Gasoline

 

[JRP3]

The output of the fuel cell is electricity and water.

Good point. I assume you'd have to carry some water to start the reaction and make up for any losses.

 

[transpondster]

The output of the fuel cell is electricity and water.

Vapour. You would need to waste some energy to condense it

 

[daniel]

So, what I want to know is what are the byproducts of converting the paste+water into H2? The big selling point of H2 is that the fuel cell eats H2+O2 and give off H2O + electricity. All nice and clean. But I don't suppose the paste turns into H2O. I'll bet there are chemicals left over. What happens to them? Where do they go?

If you can really get more energy density than lithium batteries, then maybe you're willing to sacrifice efficiency for the convenience of range. Maybe you're even willing to build infrastructure for delivering the paste to cars all across the country. But are you willing to have noxious pollutants spewed into the air? The cleanness of fuel cells no longer matters if the process of getting H2 out of the paste is dirty.

I make my own electricity for my home and my car. And in most parts of the world anybody who can afford an electric car can probably do the same, if they have a roof that gets sunlight. And if not, the grid already exists to deliver electricity to their home. There's zero advantage to me in any sort of system that requires me to buy hydrogen. And if you're off the grid or live somewhere without a grid, you ain't gonna have access to H2 paste.

 

[Merrill]

I still have a hard time understanding any advantage hydrogen has over other forms of green energy, it is expensive, dangerous and hard to find. The cost to set up a hydrogen fueling station is very expensive, and at this time good luck finding one.

 

[Guy V]

Vapour. You would need to waste some energy to condense it

Actually, condensation releases energy. Enough to be worth capturing? Or perhaps the process they describe can simply use the water in vapor form?

 

[transpondster]

Actually, condensation releases energy. Enough to be worth capturing? Or perhaps the process they describe can simply use the water in vapor form?

Condensation requires energy in form of drag and pumps / fans consumption. Released energy you can use if you connect your hydrogen car to central district heating system pipe...

 

[daniel]

I still have a hard time understanding any advantage hydrogen has over other forms of green energy, it is expensive, dangerous and hard to find. The cost to set up a hydrogen fueling station is very expensive, and at this time good luck finding one.

I agree with all of the above, except that hydrogen is not green energy. It all depends on how you produce it. It is not "hard to find." It is hard to produce. In nature, on Earth, hydrogen only exists bound into other substances, from simple H2O, water, which is abundant and everywhere, to complex hydrocarbons. The former requires more energy to release than you get from the H2, and the latter releases pollutants when you extract the H2.

Everything else you say is correct, and hydrogen is no good for energy. Unless, that is, they can solve the problem of controlled and confined thermonuclear reaction. If you can turn H into He in a controlled manner, you can get buckets of energy. They've been trying to do that for seventy years and they haven't figured it out yet.

Afterthought: There is a freely-available thermonuclear reactor we can draw energy from, and many of us here on TMC are using it today. So I guess, in a way, my car is powered by hydrogen now: Hydrogen fusion in the sun makes the light that hits my solar panels and charges my car and runs my home.

 

[Merrill]

I agree with all of the above, except that hydrogen is not green energy. It all depends on how you produce it. It is not "hard to find." It is hard to produce. In nature, on Earth, hydrogen only exists bound into other substances, from simple H2O, water, which is abundant and everywhere, to complex hydrocarbons. The former requires more energy to release than you get from the H2, and the latter releases pollutants when you extract the H2.

Everything else you say is correct, and hydrogen is no good for energy. Unless, that is, they can solve the problem of controlled and confined thermonuclear reaction. If you can turn H into He in a controlled manner, you can get buckets of energy. They've been trying to do that for seventy years and they haven't figured it out yet.

Afterthought: There is a freely-available thermonuclear reactor we can draw energy from, and many of us here on TMC are using it today. So I guess, in a way, my car is powered by hydrogen now: Hydrogen fusion in the sun makes the light that hits my solar panels and charges my car and runs my home.

Then even more of a reason to invest that money into wind and solar with battery storage.

 

[SageBrush]

Welcome back Daniel !

hydrogen is not green energy.

POV, and the same can be said for electricity

It is hard to produce.

It is not. It is inefficient to produce

Hydrogen is flammable, must be pressurized, hard to contain, and a brittling agent. Oh, and when oxidized, 40% conversion losses.

It is a little bit better than hydrocarbons ... at best.