For example, nuclear power continues to create energy at night, at 2am when there aren't many trains running.
In contrast, when an electric train pulls from the grid, it needs electricity immediately, no matter how loaded the grid is. Electric Trains running at 7pm (during the "Duck curve") will inevitably be powered by natural-gas peaker plants.
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In contrast, Hydrogen electrolysis could continue into the night and be powered by "otherwise unused" 2am or 3am electricity from nuclear power. Even if the train was running at 7pm, the electricity comes from the most advantageous time throughout the day.
That is to say: Hydrogen is a fuel, AND a battery, AND is compatible with electrification technologies thanks to the fuel cell.
Hydrogen is a storage technology, not really an energy source. Hydrogen competes with Li-ion batteries.
How many Li-ion batteries do you need to equal one 200-ton liquid H2 storage tank? At 120MJ per kg, 200-tons == 200,000 kg == 6GW-hrs of electricity. There's no Li-ion battery in the world that's anywhere close to that kind of storage capacity... and various researchers are aiming at 3000ton H2 storage tanks.
Erase 50% or even 80% of the energy due to inefficiency / costs of cryogenics, and you still have a bigger energy storage tank from H2 than anything possible with Li-ion. And the future of H2 is looking like 10x capacities are reasonable over the next 10 years.
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Whatever solar solution you were thinking, just do the same except instead of using big, expensive, heavy Li-ion batteries, replace the storage mechanism with H2 fuel cells.
I totally understand why hydrogen is a great rocket fuel. You need this high energy content and the extreme lightness for high Isp.
On land, I suppose, the energy density of 100 tons of hydrogen in one place is unnecessarily high. The fact that hydrogen has no odor, and its flame is entirely infrared, invisible, does not help.
By the same token, I think that lithium batteries have excessive energy density for large-scale land applications, like buffer storage for solar / wind power. Even a lead-acid battery, with all its environmental downsides, weight, etc is at least not a major fire hazard. I suppose that large-scale electricity storage will take off when cheaper and safer, while less dense, alternatives to lithium batteries are commercialized.
As a power source for a car, a lithium battery at least is not cryogenic. OTOH on the scale of a train this may already be not a big problem. Same possibly for an oceangoing ship, but it would be terrible to start losing fuel and power if a bad storm damages the cryogenic system.
An ideal (fantastic) system could use methane and turn it into carbon, only oxidizing the hydrogen. Sadly, similar reactions only work so far with much more complex molecules.
I thought it was UV? (Which, if anything, is even worse).
Converting methane into hydrogen is known as steam reformation. We can easily due this, but we don't want to because it is a fossil fuel.
That's literally the plan?
https://www.nrel.gov/news/program/2020/answer-to-energy-stor...
Hydrogen is a newer technology than Li-ion. But yeah, its more than capable of these things. We just gotta build out pipelines and facilities to handle it.
But no. To deliver MWs of electricity to trains requires using a ton of copper on all rail-lines, as well as advanced transistors to switch that electricity around. Hydrogen storage of electricity is a good idea and is being developed, but there are innate benefits to the fuel-methodology for applications like trains.
In particular, a pipeline will likely transmit more "energy" at cheaper costs than a bundle of copper wires. Steel and concrete pipelines are just cheaper. So instead of building expensive copper wires + expensive transistors to switch electricity all around the place, why not build pipelines?
> Wouldn't it be more efficient than transporting the hydrogen by truck and transporting the hydrogen battery on every train?
Well, first off, the most efficient form of transporting Hydrogen would be a pipeline. But lets say we're dealing with a remote area so a truck is necessary.
1kg of Hydrogen has 120MJ of power, or 0.033 MW-hrs of electricity. A singular kilogram.
https://www.energy.gov/eere/fuelcells/hydrogen-tube-trailers
These trailers can store 900kg of Hydrogen. Or in other words, 30 Megawatt-hours of Hydrogen based electricity. Larger vehicles, like trains, can likely afford to carry larger containers, possibly even cryogenic liquid-hydrogen that is even more compact.
https://demaco-cryogenics.com/blog/liquid-hydrogen-storage/
Current storage tanks from NASA can hold 270 tons of liquid Hydrogen, with plans to scale to 3000 tons of liquid hydrogen storage. That's 3000000 kg, or 100 Gigawatt-hours of energy storage per tank.
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So yeah, the amount of H2 energy storage available far exceeds what is possible with Li-ion technology.
Pipelines will be more efficient at moving Gigajoules / dozens of MW-hours at cheap costs. Trucks and trains can carry the fuel wherever they need to go. Energy storage / Hydrogen batteries will scale to far higher capacities than Li-ion could ever dream of.
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Hydrogen is an incredibly light fuel. Its difficulty in transportation is __volume__ rather than its weight. Storage technologies, such as higher pressure (700-bar or higher), and liquid cryogenics are needed for H2 storage to be effective. These technologies are just becoming possible today.
So only now can we dream of what liquid-hydrogen storage tanks can offer us. Literally 100GW-hrs of energy per liquid-hydrogen tank is feasible (while *current* prototypes from NASA are holding 9GW-hrs of energy storage).
https://www.spglobal.com/marketintelligence/en/news-insights...
For a locomotive of a train, the volume of storage is a much more important limitation than the mass.
Moreover, after adding the mass of the fuel containers, it is likely that diesel fuel has also a greater energy per mass than hydrogen.
Hydrocarbon fuel can also be transported by pipelines.
So none of these arguments show any advantage of hydrogen versus the traditional diesel fuel.
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I do think that green-hydrocarbons have a potential future. Green diesel would be a biofuel. But Hydrogen can turn into a hydrocarbon through Syngas synthesis (eventually turning into Kerosene and other "green hydrocarbon" fuels).
If the chemistry works out, maybe that's the future. But experimentation with pure H2 looks promising right now.
Even if the energy efficiency of a storage cycle is lower than when using directly the hydrogen, the savings due to easier handling and storage are huge.
Moreover, that path will allow the reuse of all the existing infrastructure for hydrocarbons, whose replacement would require a very long time and very high costs.
Maybe that's not enough for the long term, but that mix/ratio should be sufficient to bootstrap the fledgling H2 industry.
If Syngas / synthetic diesel becomes more efficient in the future, we switch to that. I'm not against experimentation or tests.
Hydrogen made from solar electricity is around 40% efficient, so it is more than 2.5 times more expensive (expensive storage and transport) than just solar and overhead electric cable. Cheaper still because you can put solar panels along the train tracks so land use is almost free. You would have much less losses if you convert solar panel 40-60V directly into high voltage the train use.
Why can't those night-time batteries be Hydrogen?
And instead of running electrical wires, why don't we pump that Hydrogen into a pipeline that goes to the train station? That way, our energy transport uses cheap steel-and-concrete to move our energy around, rather than expensive copper and transistors.
And instead of electrifying 3000 miles of track, why won't the Locomotive engine be a fuel cell that converts the H2 back into electricity on board?
If you calculate the LCOE, you'll find that using wind at night is cheaper than hydrogen. Maybe certain batteries storing solar can beat wind at cost? My point remains, don't guess "why not use my favorite X" but calculate and simulate all alternative systems and the the lowest cost of energy ofve lifetime of systems is the winner you actually build.
Transistors, transformers, and electric wires use an incredible amount of copper.
There doesn't appear to be a promising solution for seasonal storage of energy other than hydrogen.
Pumped hydro power is limited to certain areas and also doesn't scale in the same way that hydrogen does. Compressed air is sometimes mentioned but doesn't appear to make much progress.
Since the world is going to need massive amounts of seasonal storage for the sake of the stability of the energy system (which is the backbone of society), as more and more renewables are built, there just has to be a solution. And if there's only one that scales to demand, then that's what will be built.
Hydrogen (and derivatives and generally all chemical energy carriers) also have this triple synergy of huge capacity for transmission plus flexibility plus buffering.
Transmission capacity of a pipeline is massively larger than any cable.
Flexibility is given through the fact that hydrogen can spontaneously be transported to almost any location. Compare that to "spontaneously" building a new power line to an arbitrary location.
Buffering is a byproduct. As soon as the hydrogen is produced, it acts like a buffer, whether it's inside a pipeline or some tank. Compare that to electric energy transmitted via cable .. as soon as the power plant is shut down, the lights will go out.
A chemical based energy system is inherently more stable and resilient than an electrical grid, IMO.
It also turns out that we've repeatedly stopped and restarted our electrification campaign over the last hundred years, such that we have little persistent expertise and excessive costs per km. So it's not just tunnels and bridges.
In the extreme case, a railway which is 200 miles long and takes 3 trains a day will never have a positive financial case for electrification. So once you've electrified all the stuff that should have been done decades ago (like main lines with 10 trains an hour) and then pushed on to the marginal stuff (hourly rural lines) there's still a small core of lines left. You could just bite the bullet and electrify them anyway, or you could go with things like battery electric trains (good for short distances off an electric mainline) or biodiesel/green hydrogen. The latter are likely to be cheaper.
Hydrogen trains might make sense even if hydrogen cars don't, since the trains run on their tracks, according to a fixed timetable, and need little new infrastructure.
It requires a high pressure (300-bar minimum, 700-bar ideal) environment... or cryogenics to store compact liquid hydrogen.
Building a small, personal, car-tank that withstands 700-bar of pressure and survives typical car accidents is... really difficult? However, building a large train-tank that withstands a typical derailment is far easier.
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I don't think Hydrogen will ever be useful for personal cars. The pressure requirements / storage requirements look rather insane.
I know there's groups working with carbon-fiber designs and other advanced materials, but those are really expensive. Larger trains / trucks can just use standard steel to contain the Hydrogen at 700-bar of pressure (because a bigger tank is easier to scale).
But they're expensive, very expensive, because those storage tanks are extremely sophisticated. Unless those storage tank costs come down by a LOT, I don't think H2 cars will compete reasonably against other technologies (Hybrid, PHEV, or EVs)
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$50,000 for an H2 vehicle with only 180 horsepower engine is really meh.
So roughly 340km of double-track for $1.5bn.
https://en.wikipedia.org/wiki/Midland_Main_Line_railway_upgr...
With the numbers US planners are spewing out, we'd never have fast train network in Switzerland or high-speed rail across Italy, France or Spain.
The UK government estimates £600k/track-km, so even in the US with high wages it should be doable at $2 million/km per track if budgeted carefully...
Source: https://www.tagesschau.de/wirtschaft/deutsche-bahn-siemens-w...
From an engineering perspective the complication of the track electrical infrastructure and pantograph seem inferior to a hydrogen tank and fuel cells. Far less actual stuff to build and maintain.
Set against that, the miles per technical incident for electric trains are about twice that for diesel, and a train breaking down on the ECML is also disruptive, if not obviously infrastructural...
http://www.rail.co.uk/rail-news/ecml-suffers-another-failure...
The two techs are complementary.
You see this on tram systems where bridges or junctions conplicate the overhead wires.
[1] https://www.swr.de/swraktuell/baden-wuerttemberg/friedrichsh...
If we're learning one lesson right now in Germany it's probably that having some things not running on the electricity grid is potentially a good idea. Hydrogen is energy dense, burns clean and doesn't depend on any system infrastructure, which is pretty neat. I think it's underused still, afaik Japan is the only other place betting some money on it.
I don't understand about trains but I imagine that doing maintenance in one electrified line would shut down or overload other parts of the network. Also, energy transported this way could be easily stolen, they just need to pull some wires and hide underground. Also, to transport energy cheaply in long distances you need a very high voltage, that would electrify anything that gets closer to the track. That is why you see high voltage cables being only used in very high poles.
The track is divided into section, so you can turn off parts of it. It isn't one continous wire, there are unelectrified dividers.
> Also, energy transported this way could be easily stolen, they just need to pull some wires and hide underground.
The standard voltage used is 25000 volts. You can't 'just' use it, you need an entire electricity substation.
> Also, to transport energy cheaply in long distances you need a very high voltage, that would electrify anything that gets closer to the track. That is why you see high voltage cables being only used in very high poles.
About 3 metres clearance is needed to avoid arcing. Anything higher is mainly to stop something hitting it.
Source: https://www.tagesschau.de/wirtschaft/deutsche-bahn-siemens-w...