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Comment by jordanb | Hacker News Reader

Everyone I know in environmental activism hates hydrogen and sees it as green-washing the petrochemical industry.

They may feel that way, but that seems emotional rather than rational. The choices for small-scale energy sources are: batteries with all their dirty mining, biofuels taking away lots of arable land from food/textile/etc production, or fuel cells which can still involve petrochemicals (but don't have to). There are no perfect options, and strapping enough solar panels or wind turbines to a vehicle (car, bus, train, airplane, etc) to make it drivable is just not even remotely feasible.

No doubt the petrochemical companies want to continue existing, but shifting the transportation infrastructure away from directly burning gasoline and natural gas is a net win even if in the short term there are still hydrocarbons involved. Going all in on electric vehicles only is not diversifying the solution space enough.

> choices for small-scale energy sources are: batteries with all their dirty mining, biofuels taking away lots of arable land from food/textile/etc production, or fuel cells

Storage also includes flywheels and pumped hydro. Hydrogen is mostly a farce.

The key adjective there is "small-scale". There are many more alternatives when size is not an issue. Flywheels are very useful but their energy density is too low to be the primary power source for a vehicle.

The dirty mining and manufacturing of batteries is the dumbest red herring there is. It's like saying we need to get rid of toilet paper because it cuts down so many trees.

Hydrogen on the other hand clearly is pushed by fossil fuels since it leaves the door open for them to be a major player.

Hydrogen/syngas right now is the only way forward for long distance sea or plane travel, since batteries are too heavy.

We're going to get a 4x energy density improvement from lithium sulfur batteries, just as soon as production ramps up.

Wikipedia lists the energy density of kerosene as 9.7k Wh/L, and lithium sulfur at 550 Wh/L, which is not great.

Hydrogen isn't so great either.

But burning kerosene is much less efficient, and turbine engines have a much lower power density than electric motors, so knock 2/3rds off the the kerosene number.

550 Wh/L would also be for the first lithium sulfur batteries to market, they'll double that down the road.

hydrogen definitely not the only way for long distance sea, nuclear would just make so much more sense. and for place travel it also such the same as batteries, first of all its an explosive gas and second we only get less than 20%. hydrogen is just not a good solution to anything other than being a byproduct in the natural gas industry.

Though it may never prove viable, hydrogen from electrolysis of water creates no emissions other than oxygen. While large ships may be able to use nuclear power directly, the risks of a tenfold increase in small floating nuclear reactors in civilian hands are not trivial. Hydrogen provides a way to keep power generation centralized, secure, and efficient while also distributing it where needed. But this assumes an extreme excess of power, something only possible with nuclear or large-scale renewables, which may never come to pass in sufficient quantities or without even bigger problems.

I don't disagree that nuclear propulsion has a long way to go before becoming safe enough for civilian use and might require extra security and regulation forever, but we need to do something other than dumping bunker fuel waste into the sea and atmosphere even coubting in several terrorist attacks and accidents it might still end up killing less people using nuclear. As you say going with hydrogen and by extension ammonia, which is probably the only viable way to fuel ships, will require unthinkable amounts of renewables which is mostly intermittent energy meaning hydrogen electrolysis plants will have to be ramped up and down as the wind blows or the sun shines. this makes the efficiency calculations even worse for an already super wasteful undertaking. i guess we could potentially use nuclear but why waste 80-90% of the energy created by converting and then using hydrogen ? My opinion is that we need to throw much more money at making nuclear fission safer.

I think most of the heat and fuel will get wasted anyway. A nuclear-powered cargo ship is going to be closer to a nuclear-powered submarine than a nuclear-powered aircraft carrier, in terms of the number of people being supported and the needs beyond propulsion. That means running the reactor below its optimal fuel efficiency, and then intentionally discarding a portion of its heat most of the time to retain some spare capacity for demand spikes and emergencies. Of course, small-scale nuclear reactors are an active area of research, but AFAIK the results haven't been promising yet. So it's an avenue, but not the only one.

Running a reactor full-bore on shore, pumping ocean water, desalinizing it, electrolyzing it to hydrogen, cryogenically separating nitrogen from air, and combining the result to produce ammonia, might look really inefficient in isolation, but might be efficient enough when compared against the alternative. When the costs of logistics, personnel, and capital are accounted for, it might even come out ahead. That having been said, the amount of waste oxygen this would produce is immense, and could create risks of its own. Ammonia is also more likely to produce NOx when combusted in air than hydrogen is, so that's not great, either.

Nuclear would not make sense at all for long distance sea travel. Naval reactors require highly enriched fuel in order to be compact enough, so they could never be widespread on civilian ships for fear of proliferation. They're also extraordinarily expensive and require a specialized crew, and their power output is overkill for a cargo ship (but they can't really be scaled down much further).

The only real synthetic alternative is ammonia which brings it's own host of problems and potential for malicious use. while your arguments are valid, i think we can overcome most of the problems you mention with more research. at some point we'll need to make the hard decision to either give up on the environment or go nuclear and accept the extra cost of safeguarding it. It simply seems there's no other realistic alternative.

There are plenty of options that are more realistic than ship-based nuclear, such as sails and biofuels.

biofuels are not green and require huge land mass and come on dude, sails, really ?

Biofuels are carbon neutral. They require land, but a single engineered biofuel crop could grow on land that other crops couldn't. It's a promising use for the Canadian tundra that's melting.

Sails are very promising - a cargo ship would need enough fuel to maneuver in port and to generate electricity en route, but for most of the trip it could rely on (computer-controlled) sails.

Neither of these options are mature today, but they're a lot closer than nuclear-powered cargo ships.

> The only real synthetic alternative is ammonia

This is untrue.

Maersk launch a commercial 172-metre container ship running on run entirely on green methanol a bit over a year ago and has 25 more new green methanol ships in the build pipeline.

Australian companies have already contracted to supply green methanol sourced from solar farms after their build and trial of methanol shipping (tugboats) in Singapore.

> It simply seems there's no other realistic alternative.

You say that, the world disagrees.

> It's like saying we need to get rid of toilet paper because it cuts down so many trees.

Better not to trigger the bidet crowd.

What dirty mining for batteries? Please be specific. This story was always a PR drive that focused on the "dirtiness" of batteries but never compares it to the dirtiness of all the other parts of competing technologies.

And talking about the "dirtiness" of batteries but not every other single part of our industry (steel for everything, all the nasty stuff for electrolyzers, etc.) is all part of prioritizing emotional over rational. Public discussion of our energy system is definitely more emotional than rational, and I would argue that the emotional side of things means that we do a lot more fossil fuels and dirty tech, whereas a more rational approach would have us on far more solar and storage than we currently are, or plan to do.

There’s a lot of pressure for batteries to become cleaner too, which has resulted in a lot of money going into R&D of more effective chemistries comprised of more readily available materials. It’s difficult to express the sheer momentum we have in this field right now and it would be a shame if cold water got dumped on it by negative public perception, cooling investments. It’d be a textbook example of letting the perfect being the enemy of the good and of squandered potential.

Batteries require specific minerals that are largely unique to them. The amount of lithium, for example, needed for all other purposes combined is dwarfed by the amount used to make batteries. Of course all industry and mining is dirty, the question is of unique costs to each solution. You don't need to mine nearly as much lithium, even if you account for all the infrastructure and logistics, to make and distribute biofuel. But then you need to dedicate a lot of arable land, which will have other effects. The point is not to remove batteries from the discussion but to include all solutions.

Mining affects a limited local area. CO2 emissions affect the whole planet.

I understand it if you look at the receiving end. Say in Germany they built natural gas plants shortly before the war under the premise that they must be Hydrogen ready, aka right now we use natural gas but promise in a few years when Hydrogen production is there, we'll switch to Hydrogen. That can be very easily criticized as green washing of the gas plants (although a gas plant is much better than what it would have replaced, brown coal). Now with the war and the pipelines destroyed, Germany went a different route and instead runs the coal plants for a longer time.

But if you look at the production side, they are building a solar power plant. How is that green washing? There is no way to use a solar power plant other than to collect renewable energy. Either it is operational and collects renewable energy, to send it to various places, or it is not operational, but then it's been a bad investment for the investors. Now, maybe it could be part of some greater scheme where one uses this plant as the "source" of a multiple of the ammonium it can actually produce, and sells ammonium from fossil sources as made by Chilean sun. But that should then be addressed on its own, and not hamper the project itself (although of course a different location would be better that doesn't risk the operations of scientific instruments worth billions).

There's two types of hydrogen: 1) ammonia for fertilizer production and perhaps other industrial decarbonization, and 2) fantasies of energy storage, fuel, etc.

Environmentalists know of the necessity of ammonia, but push back hard on the second.

Michael Liebreich's hydrogen ladder is fairly good at summarizing an honest assessment of where hydrogen will be useful:

https://www.linkedin.com/pulse/hydrogen-ladder-version-50-mi...

And you'll see that it gets pushed in lots of very inappropriate places.

It's funny how much benefit of the doubt is given to really bad tech, like hydrogen and large nuclear reactors, despite decades of data showing that they always underperform expectations and that people who implement them always overpromise and underdeliver. It's a stark contrast to solar and wind and storage, which always seem to underpromise and overdeliver, and these technologies face huge amounts of undue skepticism not only from decision makers but also the press and the public. There's a lot of decision making in energy that is extremely disconnected from data and reality, and most of hydrogen decision making these days is disconnected from reality.

you are right that hydrogen is a fantasy.. but wait.. what is this solar and wind plus storage you speak of that overdeliver, specifically what storage are you talking about? the wind industry has heavily been pushing hydrogen as this storage at least in Germany and Denmark and as far as i know there's absolutely zero success here despite maasny years of trying

You state that energy storage is a fantasy, liebreich puts Long Duration Grid Balancing as a B on the hydrogen ladder. Sure it's going to be extremely expensive, but I don't see any cheaper alternative for countries without dark winters where also the wind can sometimes be not enough.

I agree though that it gets pushed in lots of inappropriate places, where better alternatives exist.

Environmental activists have their own biases and blind spots.

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