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mhornberger t1_j5qgd3f wrote

Reply to comment by gerkletoss in Solar powered hydrogen facility being built in California by ForHidingSquirrels

I don't think efficiency matters as much when we're talking about sunlight. The sun was going to shine anyway. When burning fuel efficiency matters more, since you're consuming a resource that you had to extract and refine. Not saying efficiency means nothing here, just that it might take a backseat to the importance of reducing the burning of fossil fuels.

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wwarnout t1_j5qijjz wrote

Here's a thought:

Using solar directly is more efficient that using it to extract H2, which is subsequently used for essentially the same purposes.

However, there are times when solar or wind have to be turned off, because they are producing more energy than can be used at the time, and storage is still not well developed.

So, rather than turning the renewables off, they could redirect the energy to extracting H2. This would make much more sense than using solar for H2 extraction instead of using it on the grid.

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Surur t1_j5qrvic wrote

That logic especially holds when you overbuilt solar and have masses of excess solar that would otherwise go to waste.

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Nah-vi t1_j5qy4y0 wrote

Couldn't you collect the water after using the fuel to drink or at the very least water plants also? Meaning even if it isn't efficient ad a fuel source it has other valuable benefits.

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Ps1on t1_j5so25a wrote

Yes, but then you have to be able to have sufficient storage of H2. I'm not sure if that's there yet. It's a highly flammable, very light gas that needs to be stored in obscene quantities over a period of months.

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cybercuzco t1_j5qozy4 wrote

Sure but if you are going to convert that H2 back into electricity you will get more electricity back if you store it in batteries.

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killcat t1_j5r64k6 wrote

As a percentage, yes, but it comes down to energy density per dollar of storage cost, and there are applications for Hydrogen gas that raw electricity can't do.

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cybercuzco t1_j5qokoj wrote

It does matter because if this is just being used as an energy storage mechanism there are probably more efficient means of storing that electricity (batteries). If they are making process hydrogen that is replacing a natural gas source then you’re right efficiency doesn’t matter.

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martinstoeckli t1_j5qt3wz wrote

Converting electricity to hydrogen and back to electricity is one of the cleanest ways to store energy, this has the potential to reduce the summer/winter differences.

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johnpseudo t1_j5tzkj4 wrote

Batteries are only more "efficient" than hydrogen when their duty cycle is relatively high. For seasonal balancing (with a duty cycle of ~1/year), hydrogen is significantly cheaper because of the lower storage costs.

For example this study:

>For storage durations longer than approximately 36 h, technologies with very low storage costs, such as geologic hydrogen storage and natural gas with CCS, offer the least-cost options for LDES and low-emission power generation capacity.

>These results share some similarities with those of previous studies while also offering unique insights. Schmidt et al.11 similarly demonstrated that hydrogen storage and CAES have the lowest costs for seasonal storage in the near term, with hydrogen becoming the least-cost technology for seasonal storage in the future. The present analysis, however, introduces a lower-cost HDV-PEM fuel cell system compared with the stationary fuel cell system considered in Schmidt et al.11 The HDV-PEM system in this analysis provides both a lower power capital cost by using the HDV-PEM fuel cell as well as a lower energy storage capital cost by using a salt cavern. These cost reductions are slightly offset by the lower capacity factor modeled for HDV-PEM systems because of their lower round-trip efficiency, but the results still indicate that HDV-PEM|Salt systems achieve the lowest LCOE at durations as low as 36 h in the future scenario, much lower than the duration estimated by Schmidt et al.11 when including all technologies.

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cybercuzco t1_j5u7epc wrote

Right but what that study fails to mention is that we don’t need seasonal storage if we are using combined wind and solar, because wind produces more in the winter and solar produces more in the summer. source

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johnpseudo t1_j5uids4 wrote

Obviously it'll depend a lot on location and availability of long-distance transmission.

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gerkletoss t1_j5qgr4c wrote

It would certainly affect whether it's preferable to biofuels

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mhornberger t1_j5qh99h wrote

Plant-based biofuels are land- and water-intensive. Putting aside recent rains, CA has been facing serious drought issues. Plant-based biofuels are just not that great.

If we scaled algae-based biofuels that picture might be different.

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gerkletoss t1_j5qijno wrote

Solar power is land-intensive.

Hence why a trade study is needed.

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mhornberger t1_j5qixij wrote

Solar can coexist with agriculture on the same land via agrivoltaics, and also with wind turbines. PV can also go on rooftops, over reservoirs, etc. Studies have already been done showing that, per acre, PV generates more energy than plant-based biofuels. "But they both use land" doesn't make them equal.

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gerkletoss t1_j5qlgv7 wrote

May I see some of these studies?

Regardless, when it comes to load-following power plants or airplanes, the balance does shift.

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expertestateattorney t1_j5qtokg wrote

I have been through that area. There are immense tracts of unused desert land.

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gerkletoss t1_j5r03w5 wrote

A) deserts have important ecology

B) we're not just talking about this one site

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SandAndAlum t1_j5sc769 wrote

The worst areas are within easy transmission range of somewhere with a winter capacity factor over 8%.

Power density is around 1MW/ha nameplate when land optimized. This is under 70m^2 (8m x 8m) per person to provide world final energy of around 10TW. This land can coexist with many other uses (such as roofs, car parking, and agrivoltaics)

The fact that you're pearl clutching over this, but not over the average 8 car parks per person at 40m^2 each or the land required to support eating beef makes your motivations fairly clear.

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gerkletoss t1_j5skjo1 wrote

I don't need a lecture from someone who can't even keep track of what I'm talking about trading.

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SandAndAlum t1_j5smffo wrote

You only dog whistled it but it's obvious nonetheless.

You're talking about more land, more pollution and more long term costin the form of gas.

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gerkletoss t1_j5smw7i wrote

I could make up far worse lies about you but it would only make me look like more of a moron than you and I'd probably get banned for it.

Maybe if you pull you head out of your ass you'll figure out that deserts are real places with real environmental impact and while they're certainly not bad places for solar installation care must be taken to avoid erosion problems due to construction and lack of plants.

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SandAndAlum t1_j5sbjym wrote

Solar uses less land than coal extraction or the largest uranium mines per unit power. There is no choice with lower impact.

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gerkletoss t1_j5skgn8 wrote

If you look back three comments you'll see that I wasn't comparing to any of those.

>There is no choice with lower impact.

For many applications there are. For instance, it's better to run my blender off the grid than to use solar hydrogen.

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[deleted] t1_j5sky5m wrote

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[deleted] t1_j5smloa wrote

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SandAndAlum t1_j5smwv0 wrote

No. You were repeating fossil fuel propaganda unrelated to the issue at hand.

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gerkletoss t1_j5sn5my wrote

They use real concerns in their propaganda because it's effective

But you'll note that I only mentioned carbon-neutral alternative technologies here, which terrifies the fossil fuel industry. Or maybe not. My hopes aren't high.

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SandAndAlum t1_j5sniku wrote

Except it's not a real concern when its less bad than any other option. By all means push for less land use, but pick the low hanging fruit first.

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gerkletoss t1_j5snsqw wrote

The other carbon-neutral options are what I was talking about you reactionary hero

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SandAndAlum t1_j5snx6r wrote

You continue to dog whistle gas with carbon capture (which is fictional) whilst not being brave enough to say it out loud.

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gerkletoss t1_j5so2bi wrote

Yes, carbon capture is on the list of things I didn't say.

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SandAndAlum t1_j5so76s wrote

Which continues to be fossil fuel propaganda.

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gerkletoss t1_j5sohfm wrote

Fossil fuel propaganda would be accusing everyone who asks questions about hydrogen generation compared to other carbon-neutral technologies of being shills regardless of whether they're suggesting that it's probably great for certain applications in other contexts and were doing so before you made your accusation.

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SandAndAlum t1_j5sp0hl wrote

You're attacking solar derived energy and dog whistling fossil fuel hydrogen. The motivation is obvious. This 'just asking questions' act fools nobody.

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