Cost to produce H2 from water, 50-55 kWh/kg Cost to liquefy H2 is 10-13 kWh/kg 1 Kg of H2 stores about 33 kWh of energy. More than 50% of the energy is wasted before transport, storage, boil off etc are concerned.
H2 does not make any sense whatever.
H2 doesn't make sense for a lot of things it's promoted for (see Michael Leibreich's Hydrogen Ladder for detail on this) but this is one area where it makes some kind of sense.
https://www.linkedin.com/pulse/hydrogen-ladder-version-50-mi...
Just give me an electric train for that distance...
If you had all of that H2, what is the additional cost to just fix some CO2 into hydrocarbons?
It feels like that would be a much simpler way to get to net zero than having to reinvent all of the infrastructure.
So much simpler that I wonder why anyone would keep trying on hydrogen. Which makes me darkly suspect that the goal is to take our attention off the solution that's already being deployed, i.e. wind and solar.
Regardless of net efficiency, that still entails collecting CO2 at a central facility (where it could have been dealt with in other ways, such as injection underground) and sprinkling it through the air as you fly over delicate ecosystems. I'm sure bankers see both as net zero, but condors might have more issues with your simpler workaround.
> sprinkling it through the air as you fly over delicate ecosystems
I wouldn’t be so sure spraying water vapour is innocuous. As long as it’s atmospheric CO2, the environmental impact of synthetic fuels is much less than rebuilding the world’s air fleet and fuelling infrastructure to accommodate hydrogen.
It takes a lot of energy to pull CO2 from the air since it is only 400ppm. It also takes energy to make hydrocarbons. This means they will be really expensive. They might be used for classic cars but can’t replace fossil fuels.
Hydrogen or ammonia have advantages that can be made from water and nitrogen. Ammonia may be good for ships and planes since can be liquid at cold temps. But can’t substitute in cars.
But according to HN armchair engineers, electricity will be free, nay, negatively priced in T+epsilon as exponential decrease in solar panel prices actually turns them negative. Or maybe even imaginary.
THEN it definitely makes sense.
https://energy.economictimes.indiatimes.com/news/oil-and-gas...
Wholesome energy prices do in fact turn negative. But then you store it in batteries and use it when they flip positive again. No complicated, expensive, delicate, dangerous, cryogenic fuel systems required.
Storing it in batteries works for short periods of up to maybe a few days.
You don't think there will be seasonal mismatch between renewable generation and electricity demand?
Because if there _is_ a seasonal mismatch, hydrogen will be needed anyway.
Even 7 day storage will likely need hydrogen
>1 Kg of H2 stores about 33 kWh of energy
as horrible as Hydrogen is, isnt that still ~two orders of magnitude better than li-ion? Pressure vessel will probably bring that down to one order of magnitude.
In cars where weight doesnt matter that much Toyota, leader when it comes to pushing BS hydrogen, is only able to get Hydrogen Yaris to do 10-14 Fuji laps https://www.youtube.com/watch?v=DGL5g91KwLA thats 45-60km of range on Hydrogen.
It makes better sense than curtailing solar or wind production. 50% is better than zero.
That being said, hydrogen is usually the worst option, but I don't think that's true for every scenario.
That gravimetric energy density is about 2 orders of magnitude higher than lithium ion batteries.
The difference in volumetric energy density is not that big though, and hydrogen is not as flexible as jet fuel or even batteries when it comes to how you can store it in the vehicle.
To be fair, high gravimetric density is a fairly large advantage for an air plane. But the bad volumetric energy density does present some serious challenges.
So why it’s not used in rockets?
It was used in the Space Shuttle and SLS uses the same engine as the shuttle.
Also nobody launches to orbit using lithium ion batteries as main propulsion.
> Also nobody launches to orbit using lithium ion batteries as main propulsion.
It can be part of the main propulsion.
https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
https://en.wikipedia.org/wiki/Electric-pump-fed_engine
That's why I phrased it that way.
Most internal combustion engine cars have a lead acid battery to start it up and run the spark plugs (or preheat the glow plugs if diesel). They don't get called "hybrid" or "battery powered" because the batteries aren't the propulsive power themselves.
This is akin to that: the batteries run the pumps, they're not the propulsive system itself.
Ion drives can be run off battery, but you can't launch with those.
Unlike a car battery though, these batteries provide a not-insignificant part of the energy that is generated by the engine. Each Rutherford engine generates around 37 mega-watts of power at sea-level (24900 N and 3.05 km/s exhaust velocity, Power = 1/2 * Thrust * v_e) and there are nine in the first stage. The first stage battery provides around one megawatt [1].
That's about 0.3% of all energy generated by the engines, which is significantly more than what a spark plug does in an ICE.
[1] https://theaeroblog.com/the-rutherford-rocket-engine-the-fir...
This is the closest we have to electric power directly powering the ascent of a rocket from Earth.
Something like a HyperCurie engine (which is also electric pump-fed), could probably lift off from a planetary body like the moon. When they used it in orbit, they actually had to wait for the batteries to charge up from solar panels between each engine burn.
> not-insignificant
> 0.3%
> the closest we have
I don't understand why you're trying to paint the battery as a significant contribution here.
Like a car battery, although it's neat that they consider it as part of the engineering, it's none of the actual thrust unless it explodes.
It is about 1 megawatt (1341 HP) of the power pushing the rocket into the sky (directly translated into exhaust velocity and therefore thrust). That would be like a spark plug generating 1 HP in a 300 HP engine (Which would exhaust the typical car battery in about 1 second if it could even push that much power out).
It is all semantics anyway.
Correction: It won't drain in a second. But my point is the same. We don't really have 1 HP spark plugs out there :)
Rough estimates I've seen say the starter motor is about that, though. (Not that I can tell real pages from GenAI ad content farms, I'm not a petrolhead).
I'd agree "it's all semantics", but yours are confusing me :P
(And for energy content, like for like is comparing the size of the fuel tank with the capacity of the battery, but cars aren't 90% fuel by weight).
How many kg’s to orbit/year vs other fuels?
Well, the article actually admits that 95% of hydrogen produced in the US is from hydrocarbons, and thus produces lots of CO2.
And if you think about it for a minute: Do CO2 emissions that occur miles away from where I'm standing right now really even exist?
There are times it makes sense - when you have a remote location you need power in that is more than batteries can provide for example. Say you need 300kW in a farm miles from the nearest supply for 3 months.
Why on earth would you want to maintain cryogenic fuel systems and delivery systems in a remote location?
Because you need power. And it’s not rocket science, it’s a shipping crate. The deliver system is a standard lorry, top it up with a can with some conpressed bottles in the back.
If you're delivering your electricity through hydrogen by lorry, you'll be cheaper just building out a transmission line. Or building 20x the number of solar panels so that you're good even on cloudy days.
As someone who has done this with both diesel and green hydrogen, no it’s not cheaper to run power, nor provide multi-megawatt solar provision
For three months? Maybe not. Getting right of way to run power lines is no joke.