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

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

#181

Post by Gibbon1 » Sat, Jul 04, 2020, 9:32 PM UTC

mongol wrote: post #132

atombender wrote: post #122

Earlier quoted context omitted.

I like this diagram from Volkswagen visualizing the energy loss at every step for hydrogen versus BEV: https://images.hgmsites.net/lrg/hydrogen-vs-electric--volksw... This image (don't know the source), which includes oil and coal, is also a good visualization: https://i.imgur.com/Wuhnlvu.png Even simpler: https://pbs.twimg.com/media/DPkaz0nX4AAcr_v.jpg

I would like to have seen more elaboration on transmission losses in the power grid. For example, if we imagine solar cells in Sahara generating energy for Europe, is power grid transmission feasible or does hydrogen look better in comparison?

I linked a paper talking about that. Losses are likely on the order of 5% per 1000km. I would think long distance transmission lines could transmit power both east and west which solves some of the time shifting issues. And south to north which solves some of the issue with low irradiance during the winter at high latitudes.

AKA Germany would probably be better off investing solar farms in southern Spain and connecting via long distance transmission lines. Only 1600km or so. Also consider sunset is an hour later in south west Spain.

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

#182

Post by pfdietz » Sat, Jul 04, 2020, 9:32 PM UTC

threatripper wrote: post #7

Hydrogen has an efficiency problem. You need to convert other forms of energy to hydrogen at a loss. Then you need to store it and transport it, which is costly and may impose quite some energy cost for cooling or compression. Then you need to convert it back to electricity, also at a loss. If you start at electricity, the electrical grid and batteries would be much more efficient. If you start at oil or gas, you cou…

> Batteries have a rare earth problem.

NiMH batteries do, but who is using those?

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

#183

Post by henrikschroder » Sat, Jul 04, 2020, 9:33 PM UTC

Dumblydorr wrote: post #18

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…

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…

> 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.

The fact that EV players actually delivered and built charging networks should offer plenty of proof as to which technology is more viable.

It took decades to build out the network of gas stations across countries. The reason it took much less to build out charging networks is because the power grid already existed, we already had 95% of the infrastructure for delivering the "fuel" for EVs.

But hydrogen companies are still talking as if it's super simple to build out a hydrogen infrastructure. Why would that not take decades as well? And that's assuming there was some kind of massive consumer demand for hydrogen vehicles, which there just isn't.

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

#184

Post by pfdietz » Sat, Jul 04, 2020, 9:35 PM UTC

nicoburns wrote: post #127

svara wrote: post #75

Earlier quoted context omitted.

Many of the things you're saying aren't correct, see my other comment (sibling to yours) for references. Nuclear is not cheap compared to photovoltaics, wind and hydro. Since the former two are bursty, overcapacity in them leads to cheap excess energy at times, which needs to be stored. Which storage method is the best depends on multiple factors, particularly on the duration of storage, capacity required and frequen…

Do we really need long-term storage? Wouldn't it be cheaper just to overprovision production?

It's best to do both.

Go play with this web site and look at the optimal solutions (for producing constant power output) under various cost assumptions, using real weather data.

https://model.energy/

Generally, the best solutions involve some overbuilding, some storage, and some combination of solar and wind. For sunny places, solar + batteries (+ a little hydrogen); for windy places, wind + hydrogen (+ a little solar and batteries).

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

#185

Post by pfdietz » Sat, Jul 04, 2020, 9:36 PM UTC

anoncake wrote: post #172

manfredo wrote: post #151

Earlier quoted context omitted.

Seasonal fluctuations in energy production are more extreme in far northern and southern latitudes. Which just so happens to be where the majority of energy consumption is located. The amount of energy storage required even to just handle the daily duck curve is staggering. To put this in perspective, the US consumed 11.5TWh of electricity daily. Global lithium ion battery production is 300GWh per year. Until some tr…

Nonsense. No one's going to use lithium ion batteries for this use case.

Right. It's one of the common anti-renewable canards that batteries would be used for more than diurnal smoothing.

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

#186

Post by pfdietz » Sat, Jul 04, 2020, 9:43 PM UTC

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.

You get much more fuel out of biomass if you add hydrogen. For example, from carbohydrates, it's basically (CH2O)n + nH2 --> (CH2)n + nH2O (hydrodeoxygenation). This can make drop-in replacements for gasoline, diesel, and jet fuel.

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

#187

Post by tuatoru » Sat, Jul 04, 2020, 9:44 PM UTC

jepler wrote: post #154

dmckeon wrote: post #138

Earlier quoted context omitted.

With regard to https://pbs.twimg.com/media/DPkaz0nX4AAcr_v.jpg if the capture and separate elements can be decentralized, then distribution and one storage phase are eliminated. In other words, if a refueling station can do solar or wind capture and electrolysis on-site, the economics are better. This would be unlikely for stations in urban or high-density areas, but for rural and suburban locations it might be a win…

Check my math: Say a fueling station needs to serve (only) 100 cars per day, providing 50kWh per car. That's 200kW average generation power needed. Ballpark, a 1 m2 solar panel can generate 200kWh/year, or 23W average. (quora answer, 2018). You need .. really? 9100 m2 of area, which is .91 hectare or 2.25 US acres. A 200kW per day (73000kWh/year) wind turbine might stand 25m tall. (uk wind energy report, 2014) Will t…

This is the point (one of the points) that Vaclav Smil makes about renewables: abysmal energy density of production (in Watts/square meter: more like 'intensity' than 'density' to me).

The only thing that beats oil is nuclear fission. With everything else, production takes up land that could be used for something else, or isn't being used for something else because it has problems such as distance or inhospitable climate or unfriendly (steep or unstable) terrain. All of which drive up maintenance costs or make the land also unusable for energy production.

There are no good solutions apart from the one that coal companies astroturfed us into nearly banning in the 1960s.

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

#188

Post by pfdietz » Sat, Jul 04, 2020, 9:47 PM UTC

walrus01 wrote: post #143

dmix wrote: post #109

Earlier quoted context omitted.

I've read about a couple of solar projects that projected x/kWh and turned out to be much worse in production. Pakistan's big deployment is one example, it was planned to be 100MW but only produced 18MW. Mostly because they didn't factor in the dust that would cover the panels, keeping them clean was very expensive (I'm curious how this applies to other proposed desert deployments). Nor factoring in the typical malai…

I'm honestly curious what is the big challenge with keeping large arrays of ground mounted panels clean in Pakistan. The prevailing wage for unskilled labor for a 6 day a week, 45-hour work week for one laborer to clean panels is probably about $250-300 a month (USD equivalent, in rupees) in that area. That would be a good wage compared to construction work or farm work in that region. With some basic equipment like…

And there are also many PV cleaning robots available. This is not self-driving car stuff, it's off the shelf technology.

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

#189

Post by manfredo » Sat, Jul 04, 2020, 9:48 PM UTC

anoncake wrote: post #172

manfredo wrote: post #151

Earlier quoted context omitted.

Seasonal fluctuations in energy production are more extreme in far northern and southern latitudes. Which just so happens to be where the majority of energy consumption is located. The amount of energy storage required even to just handle the daily duck curve is staggering. To put this in perspective, the US consumed 11.5TWh of electricity daily. Global lithium ion battery production is 300GWh per year. Until some tr…

Nonsense. No one's going to use lithium ion batteries for this use case.

Then what's the alternative? Kinetic storage is geographically limited. Th Sabatier process has end to end efficiency of ~30% not to mention it needs an external source of carbon dioxide. The remaining proposals are at the experimental stage (thermal storage, hydrogen storage).

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

#190

Post by pfdietz » Sat, Jul 04, 2020, 9:49 PM UTC

sacred_numbers wrote: post #173

nicoburns wrote: post #127

Earlier quoted context omitted.

Do we really need long-term storage? Wouldn't it be cheaper just to overprovision production?

It's almost always cheaper to overbuild renewables than to use seasonal storage. Seasonal storage is used once a year, so if you can store a Kwh of energy for $1 it still increases the cost of the stored electricity by 4-5 cents per Kwh. Let's look at a 1 Kw average output. Assume that you have 6 Kw of solar, along with 18 Kwh of batteries. This will work fine 7-8 months out of the year, but will not be sufficient fo…

> It's almost always cheaper to overbuild renewables than to use seasonal storage.

I disagree, especially at high latitudes. Try that in the UK, for example, at https://model.energy/