Hydrogen vs battery storage [on topic]

[billvon 3,110]

This has come up a few times lately so I figured I'd start a thread on it.

Hydrogen has been around forever.  It's been used as a fuel for spacecraft (the Space Shuttle's main engines used hydrogen and oxygen) as a feedstock for refinery cracking, and as an intermediate step in a great many industrial processes.  It is even planned for manufacture on Mars via a fairly clever fuel cycle, like so:

• A lander with a few hundred pounds of hydrogen lands; the rest of its tanks are empty.  The lander then takes CO2 from the air, and via the Sabatier process, turns the two ingredients into methane and water.  The water is broken down into oxygen and hydrogen.  The hydrogen is reused; the oxygen and methane are stored in the lander's tanks.  After a few months the lander has enough fuel to return to Earth.  This is called ISRP (in situ resource production) and is about the only way to get back from Mars in a reasonable time.

But that's a side note.  The 'battle' that is shaping up, if you will, is between battery and hydrogen storage of energy.  Batteries have been assumed both for grid scale storage (for peak loads and to store solar/wind) and for EV's.  This is mainly because batteries are very, very efficient and storing and releasing energy; you can see 75-99% efficiencies depending on charge/discharge rate.

They are expensive though, although that cost has been dropping rapidly.  They are now sufficiently energy dense and sufficiently cheap to make cheap long range cars available.  The one remaining problem is that the raw materials are scarce, but as lithium ion gives way to lithum phosphate and eventually sodium, that problem will decline - making batteries more and more attractive.

Hydrogen hasn't been standing still, though.  And there are now more and more companies making compact electrolyzers that are both efficient and cheap.  Off-the-shelf systems now hit 80% and smaller experimental electrolyzers are hitting 98%.  And they offer an interesting niche - as solar and wind get built out, there are times when the grid cannot accept all the power that they produce.  During one day last spring, for example, solar/wind/hydro produced 103% of California's power needs.  (The 3% was exported.)  This means that pretty soon we will see periods where way more power than the local grid needs will be produced by renewables.  

At that point you can curtail (shut down generation) or find other loads.  Batteries are a good load, but their cost goes up by how much energy you store.  Hydrogen is the opposite - you pay for power, but energy (storage) is very, very cheap.

More and more companies are making small (two shipping containers) electrolyzers that will take 10 megawatts of power and convert water to hydrogen with the power.  And these go for a few million.  If energy is free, that sort of system will recoup its cost in 3-4 years.   And more and more often, energy will be free for part of the day, especially near solar and wind farms.

And this is starting to happen.  Several natural gas plants in the LA area now run on a 70/30 methane/hydrogen mix, and fuel cell peakers are in the planning stages.

I used to think that hydrogen was going to be a non-starter for both storage and vehicles until we had high temperature nuclear reactors that could do thermal dissociation of water.  But the advent of efficient and cheap electrolyzers - along with the unexpected problem of having too much free energy - has been making me rethink that.  It also enables some solutions (like aviation) that are decades away from being doable with batteries.

So in the future you may see hydrogen start to creep into wider use as a storage medium and as a motor fuel.  Rapid reductions in battery cost will slow that down, but hydrogen will continue to be a more and more viable option as time goes on.

[airdvr 210]

Hydrogen powered vehicles have been talked about since I was young.  I thought the drawback was the perception of driving around in a hydrogen bomb.

[wmw999 2,584]

7 minutes ago, airdvr said:

Hydrogen powered vehicles have been talked about since I was young.  I thought the drawback was the perception of driving around in a hydrogen bomb.

Stored like the Hindenburg, yeah. But as the memory of that fades, and the price of gasoline increases, people will be happy to try new things. Rich people at first because it'll be expensive, but that's how it always is.

Wendy P.

[olofscience 492]

The main problem is not generating hydrogen from electrolysis, but rather storing it.

The weight and volumetric energy density is just too low. You can liquefy it, or compress it, then you'll have massive compression energy losses. (compression will increase the temperature, which will then leak out)

 

This will probably be less of a problem where space isn't a constraint such as grid energy or fixed installations, but vehicles like cars or aircraft the storage density is the annoying limitation. Some suggested solutions are attaching it to nitrogen as ammonia (extremely toxic) or, attaching the hydrogen to a carbon atom as methane or a longer chain like kerosene - which will generate CO2 when burned. But if that carbon atom wasn't dug up from the ground at least it wouldn't contribute to climate change.

[billvon 3,110]

3 hours ago, olofscience said:

The main problem is not generating hydrogen from electrolysis, but rather storing it.

The weight and volumetric energy density is just too low. You can liquefy it, or compress it, then you'll have massive compression energy losses. (compression will increase the temperature, which will then leak out)

 

This will probably be less of a problem where space isn't a constraint such as grid energy or fixed installations, but vehicles like cars or aircraft the storage density is the annoying limitation. Some suggested solutions are attaching it to nitrogen as ammonia (extremely toxic) or, attaching the hydrogen to a carbon atom as methane or a longer chain like kerosene - which will generate CO2 when burned. But if that carbon atom wasn't dug up from the ground at least it wouldn't contribute to climate change.

Storing it isn't a big deal for larger installations.  It takes about 4x the volume to store the same energy of hydrogen, at the same pressure, as an equivalent amount of natural gas.  And tanks are cheap.

Yes, for applications like aviation you have to liquefy it, which is an energy hog.  But for applications like cars simple compression will give you a 400-mile range.

One benefit of hydrogen (and methane made from hydrogen) is that it can be used in fuel cell cars* OR burned directly in turbines of IC engines.  Far less efficient of course, but it does give you that other option.

 

(* - methane usage requires a reformer)

[JerryBaumchen 1,465]

4 hours ago, billvon said:

Storing it isn't a big deal for larger installations.  It takes about 4x the volume to store the same energy of hydrogen, at the same pressure, as an equivalent amount of natural gas.  And tanks are cheap.

Yes, for applications like aviation you have to liquefy it, which is an energy hog.  But for applications like cars simple compression will give you a 400-mile range.

One benefit of hydrogen (and methane made from hydrogen) is that it can be used in fuel cell cars* OR burned directly in turbines of IC engines.  Far less efficient of course, but it does give you that other option.

 

(* - methane usage requires a reformer)

Hi Bill,

Not that I am any expert in these matters, but I have been giving this some thought.

I think that the EV's are a short-term intermediate solution until we develop the next fuel source.  I do think it might just be hydrogen; but, who knows what it will be.

In your area, Southern California, one can buy a Toyota Mirai; only because there is an infrastructure to fuel it.

Toyota Mirai - Wikipedia

Jerry Baumchen

PS)  I recently saw an ad for a Jeep EV.  It touted it's off-road capabilities.  To overcome the no-plugins-here problem, it has a solar panel that you can setup out in the boonies to charge the car.  It takes about 36 hours of good, solid sun to fully charge it; but, it is one option for those that like to go out into the boonies.

2023 Jeep® Wrangler 4xe - Electric 4x4 Hybrid SUV Freedom

Edited April 17, 2023 by JerryBaumchen

[billvon 3,110]

37 minutes ago, JerryBaumchen said:

In your area, Southern California, one can buy a Toyota Mirai; only because there is an infrastructure to fuel it.

Right, and that's one huge advantage that BEV's have over hydrogen - we already have a power grid.  All that has to be built from scratch if we want to use it as a motor fuel.

[wolfriverjoe 1,523]

9 hours ago, airdvr said:

Hydrogen powered vehicles have been talked about since I was young.  I thought the drawback was the perception of driving around in a hydrogen bomb.

Slightly off topic, but storing pressurized hydrogen isn't all that different from CNG or propane, and those have been used in vehicles for a while, with very few issues.

One reason for the few issues is that the pressurized tanks are external. If they get damaged in an accident, the gas leaks out, diffuses into the air and doesn't present much problem after a little while. 
For a short period, yes, there's an explosive mixture at the scene, but it's not there very long, and less so if it's windy.

Flip side of that, local to me, a CNG powered straight truck had a forklift in the back. Forklift broke loose (or wasn't secured properly), moved forward, forks pierced the fuel tanks and the truck went up in a fireball (not really an 'explosion'). Pretty spectacular.