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Comment on Surface area required to power the whole world by solar power

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The area needed is not really a problem for solar power. It's storage. We need power when it's dark, probably even more then than when there's daylight.

So implement storage. Build more capacity than you need for momentary power and use the excess to charge batteries or raise water columns. Build still more excess capacity, charge local storage at the solar plant or at intermediate locations, and use the rest of the excess at the point of consumption to charge storage there.

That's a lot of solar generators. So the sooner we start, the sooner we'll get there. The interesting thing is, just as better computers help us design and build still better computers, increasingly available energy will drive the cost of existing energy down, reducing the cost of energy used to build and maintain new capacity.

If we can only power the world half the day with solar, then that's a large fraction of our power that we don't have to burn oil or coal or biomass (food) for. If we can only power half the world half the day, it's still a win. If we can only make it through part of the night before lighting up an oil generator, it's still a win.

It astounds me that we're living in a blowtorch and we do essentially nothing with it, fight wars over oil, spew oil and emissions all over the world, and watch the elderly and poor die from lack of heat or cooling.

> So implement storage. Build more capacity than you need for momentary power and use the excess to charge batteries or raise water columns. Build still more excess capacity, charge local storage at the solar plant or at intermediate locations, and use the rest of the excess at the point of consumption to charge storage there.

You're assuming that that's economically viable. If it is, why aren't you going all-in with your money?

> That's a lot of solar generators. So the sooner we start, the sooner we'll get there.

Nope. We'll end up with a lot of old-tech solar that isn't as good as what we'll get by waiting.

> If we can only make it through part of the night before lighting up an oil generator, it's still a win.

Only if you ignore costs.

Spending $100 today on a solar system that is half as cost-effective as one that becomes available in 2 years is a good idea in some circumstances but not all. That's relevant because solar systems are not static.

> increasingly available energy will drive the cost of existing energy down

That's not necessarily true. It depends on costs. For example, we can get energy by burning diamonds. However, doing so will not drive the cost of existing energy down.

"Nope. We'll end up with a lot of old-tech solar that isn't as good as what we'll get by waiting."

No, we'll still get the years of use from the "old tech" while new tech is being developed, partly on the back of what was learned by bothering to develop the old tech in the first place.

What if we decided not to build cars until we developed the Prius? Or computers until the iPhone? You have to go through the stages, tech doesn't happen fully realized without what went before.

> "Nope. We'll end up with a lot of old-tech solar that isn't as good as what we'll get by waiting."

> No, we'll still get the years of use from the "old tech" while new tech is being developed

(NB)-C < (N-k)B'-C in some cases. (Yes, I realize that NB ignores time value of money. For N>>k, that can be reasonable if C is not too large.)

The numbers matter.

> What if we decided not to build cars until we developed the Prius?

What if we didn't invent false choices? (Hint: I'm not saying always wait.)

You're the one insisting that all-in is always the right solution. That's simply false, as is always wait.

The numbers always matter and they're often context dependent. (Example - pretty crappy solar made sense in some situations while it didn't in other situations. Better solar makes sense in some of the latter, but not all. And so on.)

"You're the one insisting that all-in is always the right solution."

I never said the words "all in," and you complained above that I'm not going all in. I'm confused.

In fact I'm opposed to "it must work 100% or it's useless, and if we do it we must do it 100%." I thought that was clear, but I guess not.

> I never said the words "all in,"

Your response to every cost-based objection was "more" and "build it".

> you complained above that I'm not going all in. I'm confused

You've said that spending on solar is necessarily good and the more the better. If you're serious, that's how you've spent your money and every dime that you can borrow.

That's why I asked what you've done with your money. Surely you're not going to say that other people should spend money on something that you're unwilling to go "all in" on. Right?

> In fact I'm opposed to ... if we do it we must do it 100%." I thought that was clear, but I guess not.

Let's review what you wrote.

> That's a lot of solar generators. So the sooner we start, the sooner we'll get there.

> The interesting thing is, just as better computers help us design and build still better computers, increasingly available energy will drive the cost of existing energy down, reducing the cost of energy used to build and maintain new capacity.

Which doesn't imply that spending on solar is a good idea. Spending too much on an energy source leads to less energy, not more. However, the fact that your statement is false doesn't mean that you didn't make it.

and you complained above that I'm not going all in

If you need to build a complete parallel power generation infrastructure which must be capable of satisfying peak power demand on its own then it's almost irrelevant whether that infrastructure is battery powered or coal powered (from an economics standpoint). Not to mention that nobody's created anything even remotely capable of being used to generate peak (or even base) power loads using only stored energy.

This tidy infographic makes it seem like we could start the switch to PV power tomorrow if only we really cared to do so. However, the truth is far different. Not only do we lack the manufacturing capacity, by orders of magnitude, to produce enough PV panels, we do not have the operational experience in creating the sort of power storage systems that would be necessary if PV sources dominated base electrical power generation. This is not a solved problem.

That's right, storage is all too often forgotten.

Some ways energy can be stored:

- kinetic energy storage e.g. spinning flywheel

- potential energy storage e.g. pump water at an altitude

- thermal energy e.g I read somewhere that molten salt can store heat for hours. i.e. steam can be produced to spin a turbine.

Also, any human artifact which shows up as a box – not a dot – on a map of this scale is pretty darn huge. We currently probably couldn’t even manufacture all the solar panels or mirrors required, even if we wanted to.

Long distance power transfer might alleviate some power storage worries, but that is a huge engineering challenge in itself. It would also increase the required area – probably considerably – and we would – again – end up with a centralized power system which absolutely depends on international cooperation, you know, kinda like oil (not to say that’s a bad thing, it just adds another point of failure).

That’s not to say solar power is forever and always not feasible. I think it’s an interesting challenge and we might expect at least some success.

Hydrogen could be a solution for storage, transportation. And there is a possibility to find a more direct way to produce hydrogen with solar power that photovoltaics and electrolysis.

Hydrogen via electrolysis is not a good solution for grid-scale storage. The cycle efficiency is just way too low.

Correct me if I'm wrong, but it seems that the world has moved away from hydrogen in favor of batteries?

There's the cycle efficiency, but it's probably also a factor that we have a very well developed infrastructure for shipping electrical power around, while pretty much none for hydrogen.

You know solar panel systems often have batteries, right?

Yep. I also know that they're pretty inefficient and expensive and toxic to manufacture and dispose of. Which makes them a problem for large-scale solar installations.

Solar is great for when there's sun. Once the sun's out, not so much.

I remember reading somewhere a while back that the investment in solar panels doesn't really pay off because of the somewhat low life expectancy (~10 years) and high costs. Is that because of the batteries also?

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