Solar energy solves global warming • Hacker News Board

Re: Solar energy solves global warming

#81

Post by rasz » Tue, Jul 11, 2023, 6:42 PM UTC

AlanSE wrote: post #74

hannob wrote: post #17

When considering synthetic chemicals made from solar energy, methane is probably one of the last you should consider. Making any type of chemical energy carrier comes with substantial losses, so whenever you can, using electricity directly is better. If you absolutely need a chemical energy carrier, the first one you will look at is hydrogen, because it's the simplest and you avoid all the direct air capture or other…

I've been following Terraform Industries for a while, and it does strike me as obvious that H2 will be the preferred form of energy storage medium in the long run, not just an intermediate species. Depending on the conditions, if you're doing day-night energy storage, then you would like to fill up the H2 tank and then burn it when demand ramps up. The only role I see for methane is when your H2 tank is already fille…

>Right now California is something like 35% solar + wind energy, and the "duck curve" is nearly maxing out. This was predicted in extreme specificity 20 years ago

Legislated. Its easy to predict something if you write it into law resulting in shutdown of Nuclear power station (Diablo Canyon)

>The main driver deterring PG&E from seeking a 20-year operating licence extension is the 2015 renewable portfolio standard (RPS) of producing 50% of its electricity from qualified renewable energy sources by 2030. PG&E’s model for the future cost of operating Diablo Canyon indicated that the cost per kilowatt hour was going to almost double, since the company would be forced to lower the amount of power it could produce from the plant in order to meet the state’s requirement. Dropping the capacity factor from the current 92% to say 50% would virtually double the price per kilowatt hour since costs are largely fixed.

>The state law which effectively dictates that by 2030 Diablo Canyon should operate at lower capacity each year and buy in power from intermittent renewables has apparently sealed the fate of the plant.

Re: Solar energy solves global warming

#82

Post by Gibbon1 » Tue, Jul 11, 2023, 6:47 PM UTC

foxyv wrote: post #35

hannob wrote: post #17

When considering synthetic chemicals made from solar energy, methane is probably one of the last you should consider. Making any type of chemical energy carrier comes with substantial losses, so whenever you can, using electricity directly is better. If you absolutely need a chemical energy carrier, the first one you will look at is hydrogen, because it's the simplest and you avoid all the direct air capture or other…

The problem with hydrogen is the storage. Although electrolysis and other methods of generating hydrogen are fairly efficient, the cost to compress it is obscene. Sabatier production of Methane is comparable, however we already have infrastructure to use Methane and storage is a solved problem. Methanol production requires methane as a synthesis gas so it just adds another step. Plant based methanol has all the same…

I think at this point it's just batteries. You can just quietly[1] site them on random brownfield land and be done with it.

[1] Quietly pull the permits, drop the batteries, and connect to the grid without alerting the Sierra Club or the usual obstructionists.

Re: Solar energy solves global warming

#83

Post by jfengel » Tue, Jul 11, 2023, 6:50 PM UTC

goethes_kind wrote: post #47

Which is easier: 1. Build solar and wind, anywhere across the globe to 4x overcapacity, and then use power-to-gas technology to store the energy into synthetic hydrocarbons, which can be plugged directly into our current infrastructure. 2. Reinvent the whole of society to run on lithium batteries.

Lithium batteries are used mainly in transportation. And we're already shifting towards them, because they're just plain better.

If we were to start over from scratch, the whole notion of covering the landscape with chemical dispensers would be considered absurd: smelly, toxic, and inconvenient. Why wouldn't you just go home and plug your car into your house? Why have a car with thousands of precision moving parts when you can just have a battery on an oversized skateboard?

We already have electric distribution infrastructure. It needs to be upgraded, but not created from scratch. The only thing that needs large lithium batteries is vehicles. You can use different chemistries for stable objects like the grid itself, or your house -- which is a nice bonus, in that you can run your house even when the infrastructure is down.

And then you can let a whole separate parallel energy infrastructure degrade and vanish. No more gas pipelines or gasoline tankers as we gradually get rid of the dependencies on them. It's not "current infrastructure" forever: it has to be maintained. If we're going to do maintenance anyway, why not put it into the existing electric grid rather than both that and the fossil fuel system?

Re: Solar energy solves global warming

#84

Post by ZeroGravitas » Tue, Jul 11, 2023, 6:51 PM UTC

kibwen wrote: post #79

BobbyJo wrote: post #60

Earlier quoted context omitted.

Not really. The reason coal was so popular was because you didn't really need any specialized infrastructure. It is a solid you can just ship using the same trains and trucks you use for TVs and apples. So you're really only giving up the mines and power plants.

This seems to be arguing that the existence of natural gas pipe infrastructure is somehow a benefit of natural gas, rather than a downside. The pipes are an expense, to say nothing of the fact that even our best-maintained pipes are leaking 2% of their gas directly into the atmosphere per year (the worst are leaking double or triple that). A hunk of coal that falls off a truck doesn't contribute to emissions; a leaky…

Coal mining is also a major source of methane emissions:

https://www.iea.org/reports/global-methane-tracker-2023/stra...

Re: Solar energy solves global warming

#85

Post by pfdietz » Tue, Jul 11, 2023, 6:56 PM UTC

mirko22 wrote: post #59

jussij wrote: post #38

Earlier quoted context omitted.

Nuclear power plants seem to take a long time to get right, which means they end up being very expensive. As an example, consider the new Olkiluoto-3 nuclear plant built in Finland. That reactor was commission just a few months ago, but its build was 12 years behind schedule. The delay to that project saw the original 3 billion Euro price tag more than triple with a final cost closer to 11 billion.

And they will be there for half a century as opposed to wind turbines and solar panels which will have to be replaced and are hard to recycle…

It would be perfectly fine if we just landfilled wind turbines and solar panels. It's not like silicon or fiberglass are rare. The whole recycling business here is more fetish than obstacle.

Re: Solar energy solves global warming

#86

Post by jnwatson » Tue, Jul 11, 2023, 6:57 PM UTC

feoren wrote: post #68

stickyricky wrote: post #12

Earlier quoted context omitted.

Doesn't methane break down in the atmosphere relatively quickly? I think the goal of this proposal is to reduce CO2 in the atmosphere. Producing hydrogen doesn't contribute to that goal (which isn't to say its a bad idea only that the hydrogen production facilities can exist independently of this proposal).

If you turn 100kg of CO2 into Methane you get about 36kg. Methane is somewhere around 25x (potentially 31x) worse for global warming than CO2 by weight, so you end up with 909kg of "Carbon Dioxide equivalent", or CO2e. Let's say 2% of that leaks to atmosphere, and you burn the other 98%. Burning the 98% gets you back 98kg of CO2 (it's just the reverse process), plus 2% of that 909kg CO2e, and you end up with 116kg of…

Thank you. This is the calculation I was looking for.

2% leakage is very conservative. The amount of additional pipeline infrastructure necessary to achieve this at scale is daunting. It will have a lot of leaks.

Re: Solar energy solves global warming

#87

Post by pfdietz » Tue, Jul 11, 2023, 6:57 PM UTC

hannob wrote: post #77

NickM wrote: post #53

Earlier quoted context omitted.

the first one you will look at is hydrogen, because it's the simplest Simplest chemically != simplest to use in practice. There are already millions of miles of natural gas pipelines leading directly to peoples' homes, and those pipelines cannot be used with hydrogen (not to mention all the appliances they feed). Renewable methane is a dead simple drop-in replacement for natural gas. None of the other alternatives yo…

None of these chemicals will be used in people's homes in any meaningful quantity. That's just not going to happen due to the conersion inefficiencies.

Right. The more efficient way to use methane to heat a home (vs. current furnaces) is to burn it in a CC power plant and heat the home with a heat pump.

Re: Solar energy solves global warming

#88

Post by pfdietz » Tue, Jul 11, 2023, 6:59 PM UTC

kibwen wrote: post #42

oh_sigh wrote: post #41

Earlier quoted context omitted.

Exactly - it is an argument for continuing to use coal, because we have valuable infrastructure even though we know how bad it is for the environment. Which explains why it is so hard to stop using coal.

In the US, the share of power being generated by coal has fallen from 50% in 2005 to 20% in 2022. (In absolute terms, which is what really matters in an emissions context, it's fallen from 2T kwh to 0.75.) To phase out existing infrastructure just takes incentives and time (and 18 years isn't even that much time on the scale of infrastructure investments). The same can happen to methane infrastructure, especially sin…

And the US has stopped building new coal fired power plants, so a decay to zero is just a matter of time (although it could and should be accelerated.)

Re: Solar energy solves global warming

#89

Post by pfdietz » Tue, Jul 11, 2023, 7:01 PM UTC

perlgeek wrote: post #56

hannob wrote: post #17

When considering synthetic chemicals made from solar energy, methane is probably one of the last you should consider. Making any type of chemical energy carrier comes with substantial losses, so whenever you can, using electricity directly is better. If you absolutely need a chemical energy carrier, the first one you will look at is hydrogen, because it's the simplest and you avoid all the direct air capture or other…

Once thing that's missing (from both the article here, and for example the whole hydrogen discussion in Germany) is the round-trip efficiency. Now the author of the article would likely argue that with prices dropping as fast as they do, a 60% efficiency is just a few years delay away from being economically efficient. (A quick search came up with a 68% efficiency for fuel cells and "80% - 95%" for electrolysis, putt…

The relevant applications for hydrogen are ones where efficiency doesn't much matter (long term storage, rare event grid backup). What matters is minimizing capital cost, which probably means using combustion turbines, not fuel cells.

Re: Solar energy solves global warming

#90

Post by pfdietz » Tue, Jul 11, 2023, 7:02 PM UTC

detourdog wrote: post #9

V__ wrote: post #4

> In the future, we will still have CO2 credits. But instead of allowing companies to release CO2 into the air… Credits might allow companies to capture co2. The article then goes on to explain that solar + co2 capture results in methane. But isn't this at best co2 neutral? Since nearly all use-cases for methane would release the co2 again and would make the credits' comparison pointless? Besides that, will methane a…

Anaerobic digestion produces methane. The thinking is recently produced carbon and will be presumably immediately re-absorbed by the surrounding plants in the next growing season. This acting as carbon balanced energy source. A smaller amount of hydrogen is also produced.

Biogas is a mixture of methane and CO2. It's been discussed to separate out the CO2 (easy because it's at such a high concentration) and sequester it. This makes biogas net carbon negative. Alternately, hydrogen can be added to convert the CO2 into additional fuel.

The downside is the large land area needed to make the biomass that gets digested. In a fossil fuel free future, carbon-containing waste streams will be valuable as feedstocks (for chemicals, for liquid fuels that cannot be electrified easily), so there will be competition for these streams.