After many false starts, hydrogen power might now bear fruit • Hacker News Board

Re: After many false starts, hydrogen power might now bear fruit

#111

Post by darksaints » Sat, Jul 04, 2020, 6:00 PM UTC

speedgoose wrote: post #6

I used to drive a hydrogen car once in a while a few years ago. It was nice to fill the car in a few minutes and get about 300km of range, but that was it. With the hydrogen you have so few refueling stations, they are very expensive, that range anxiety is a thing. To not improve things, reliability is very poor. My work had a hydrogen refueling station on its parking. It was often broken and actually a bit scary to…

Hydrogen may never be competitive with batteries for intermittently used passenger cars, but not all vehicles are intermittently used passenger cars. There is a lot of evidence that hydrogen can be competitive and potentially superior for vehicles which are used all day long, like taxis, delivery vehicles, etc.. And for continuous high power applications like maritime and aviation, batteries are so far from a realistic possibility that at best they are research projects. Batteries might work for ultra low range applications of trucking, like LTL and local delivery, but a lot of useful hauling capacity is given up by hauling batteries around.

Re: After many false starts, hydrogen power might now bear fruit

#112

Post by mrtnmcc » Sat, Jul 04, 2020, 6:01 PM UTC

Something practical not mentioned here is that the proton exchange membrane in fuel cells generally degrade in a few years and need to be replaced. This is a major expense. Degradation is accelerated if the hydrogen (fuel) or oxygen (from environment) are not pure.

Re: After many false starts, hydrogen power might now bear fruit

#113

Post by elago » Sat, Jul 04, 2020, 6:03 PM UTC

dredmorbius wrote: post #100

carapace wrote: post #91

Hydrogen is sexy but alcohol matches our existing context better. Small-scale alcohol fuel production integrated into regenerative agriculture farms is different from mass ethanol production. You can ferment anything that has starch or sugar, the leftovers from the distillation can be composted or fed to livestock. Most existing internal combustion engines can be modified to use alcohol fuel. And it's carbon-neutral.

Feedstock is the problem here: there's simply not enough net primary productivity on the planet, and humans already appropriate ~20%. There are some marginal gains possible, but on the order of single-digit percentages of present fossil fuel consumption. Maybe low double-digits. The US had a largely biofuel based transport system in 1900. Horses consumed 20% of all US grain production, the population was under 100m,…

According to the U.S. Department of Agriculture, the U.S. has 434,164,946 acres of “cropland”—land that is able to be worked in an industrial fashion (monoculture). This is the prime, level, and generally deep agricultural soil. In addition to cropland, the U.S. has 939,279,056 acres of “farmland.” This land is also good for agriculture, but it’s not as level and the soil not as deep. Additionally, there is a vast amount of acreage—swamps, arid or sloped land, even rivers, oceans, and ponds—that the USDA doesn’t count as cropland or farmland, but which is still suitable for growing specialized energy crops.

Of its nearly half a billion acres of prime cropland, the U.S. uses only 72.1 million acres for corn in an average year. The land used for corn takes up only 16.6% of our prime cropland, and only 7.45% of our total agricultural land.

Even if, for alcohol production, we used only what the USDA considers prime flat cropland, we would still have to produce only 368.5 gallons of alcohol per acre to meet 100% of the demand for transportation fuel at today’s levels. Corn could easily produce this level—and a wide variety of standard crops yield up to triple this.

Re: After many false starts, hydrogen power might now bear fruit

#114

Post by darksaints » Sat, Jul 04, 2020, 6:06 PM UTC

Certhas wrote: post #58

Dumblydorr wrote: post #18

Earlier quoted context omitted.

The issue of charging was also there with BEVs, until Tesla straight up built a huge network of superchargers. The players in hydrogen say they will do the same. But for personal vehicles, hydrogen won't math out, it's greatest advantage is its energy density for trucks. It's for long range trucks that we will see hydrogen first. Green hydrogen will act as energy storage, big renewables grids can dump excess into gre…

Hydrogen to avoid curtailment is key. Hydrogen is super inefficient. But if you would be dumping the energy otherwise that doesn't matter.

Efficiency isn't, and never has been, a deal breaker. There are hundreds of millions of vehicles that have been built with efficiency levels far lower than the best in class for ICE, and they're still used. Efficiency is just one factor of many that contribute to cost of ownership and operation.

Even then, fuel cells are not super inefficient. At the low end of efficiency, PEM fuel cells are already more efficient than the vast majority of current generation ICE vehicles. And with SOFCs with novel heat recuperation technologies, 85-90% efficiencies are already achievable.

Re: After many false starts, hydrogen power might now bear fruit

#115

Post by xyzzyz » Sat, Jul 04, 2020, 6:08 PM UTC

weswpg wrote: post #94

xyzzyz wrote: post #92

Earlier quoted context omitted.

> For example, from food waste through yeast and other methods. How is it better than generating biogas from biomaterial, something we already do at industrial scale? What’s the advantage of biohydrogen over biomethane?

isn't methane much worse for the environment than generating power from hydrogren?

If you generate the methane from biomass, and then burn it all without leaking any, I can’t see how it can be in any way worse for environment than biohydrogen.

Re: After many false starts, hydrogen power might now bear fruit

#116

Post by darksaints » Sat, Jul 04, 2020, 6:23 PM UTC

bogdanu wrote: post #40

Dumblydorr wrote: post #18

Earlier quoted context omitted.

The issue of charging was also there with BEVs, until Tesla straight up built a huge network of superchargers. The players in hydrogen say they will do the same. But for personal vehicles, hydrogen won't math out, it's greatest advantage is its energy density for trucks. It's for long range trucks that we will see hydrogen first. Green hydrogen will act as energy storage, big renewables grids can dump excess into gre…

You can't charge your hydrogen car at home, not to mention without any special and expensive equipment.

Maybe not with current production cars, but there is plenty of available technology that would allow for it. Fuel cells can be reversible...meaning the same cell that takes hydrogen and oxygen and turns it into electricity and water, can do the reverse: take water and electricity and turn it into hydrogen and oxygen.

Re: After many false starts, hydrogen power might now bear fruit

#117

Post by dmix » Sat, Jul 04, 2020, 6:27 PM UTC

Majromax wrote: post #11

This article looks like a fine discussion about the economics of hydrogen production, but unless I've missed something it skips over the immense storage difficulty. Hydrogen is a difficult thing to manage in quantity. Its density is fantastically low, so storing it in gas form requires absurd pressures -- an inherent risk to any vehicle. Storing it in liquid form goes a long way towards solving the density/pressure p…

Now I'm curious how Hyundai or the stations actually produce the hydrogen fuel.

Edit: this video had a good overview of the various production methods, including on-site at the fuel station https://www.youtube.com/watch?v=f7MzFfuNOtY

Re: After many false starts, hydrogen power might now bear fruit

#118

Post by darksaints » Sat, Jul 04, 2020, 6:31 PM UTC

Majromax wrote: post #11

This article looks like a fine discussion about the economics of hydrogen production, but unless I've missed something it skips over the immense storage difficulty. Hydrogen is a difficult thing to manage in quantity. Its density is fantastically low, so storing it in gas form requires absurd pressures -- an inherent risk to any vehicle. Storing it in liquid form goes a long way towards solving the density/pressure p…

We don't need to rely on metals for hydrogen storage...composites work just fine. And for use cases like maritime and aviation power systems, cryogenic storage isn't necessary. At all. Because even with simple styrofoam insulation, consumption rates vastly exceed evaporation rates.

Re: After many false starts, hydrogen power might now bear fruit

#119

Post by [deleted] » Sat, Jul 04, 2020, 6:44 PM UTC

[deleted]

Re: After many false starts, hydrogen power might now bear fruit

#120

Post by eqvinox » Sat, Jul 04, 2020, 6:46 PM UTC

RobertoG wrote: post #36

Dumblydorr wrote: post #18

Earlier quoted context omitted.

The issue of charging was also there with BEVs, until Tesla straight up built a huge network of superchargers. The players in hydrogen say they will do the same. But for personal vehicles, hydrogen won't math out, it's greatest advantage is its energy density for trucks. It's for long range trucks that we will see hydrogen first. Green hydrogen will act as energy storage, big renewables grids can dump excess into gre…

Maybe ships is an even better fit than trucks?

Or non-electrified railways. A modern "diesel" engine is actually diesel-electrical anyways, since curiously diesel->electric->movement is more efficient than straight diesel->movement. For a hydrogen-electrical engine you could presumably stick one or two special tanker cars behind it with the necessary tech to keep it cool. The engine could even be dual-mode and use electrification where available (like this one already does for diesel: https://en.wikipedia.org/wiki/Bombardier_ALP-45DP )

For comparison, an ES44AC [https://en.wikipedia.org/wiki/GE_Evolution_Series] carries 18900l of diesel (weighing 15.7 tons), which at 38.6 MJ/l rounds to 730GJ of energy. Hydrogen seems to have a specific energy of 120-142 MJ/kg, using the conservative 120 that's about 6.1 tons of hydrogen, but now for the volume... https://www.energy.gov/eere/fuelcells/hydrogen-storage lists "0.03kg/l" as a "system target"... so 6.1 tons is 203,333l. That's 2 conventional tank cars (but those don't have any cooling or pressurization systems.)

(Of course this assumes the efficiency of diesel->electrical and hydrogen->electrical to be similar, which is not the case.)

P.S.: https://en.wikipedia.org/wiki/Hydrail & https://www.bbc.com/future/article/20200227-how-hydrogen-pow...