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How cheap does solar power need to get before it takes over the world?

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Re: How cheap does solar power need to get before it takes over the world?

#101

Post by ZeroGravitas »

erikpukinskis wrote: post #36
WaylonKenning wrote: post #27

Earlier quoted context omitted.

Everyone seems a bit obsessed by batteries as a storage method, when we have more traditional methods: - Pumped-storage hydroelectricity - https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... . Sure it's not suitable everywhere. - There's always Molten Salt as well - http://www.solarreserve.com/en/technology/molten-salt-energy... . Also, solar isn't the be all and end all of renewable energy generation. Wi…

Batteries have some advantages that can offset the cost a little: 1) You can move them around, as in an electric car. That's useful if you want to do mobile stuff like driving. Or if you just flat-out want to move the facility somewhere it will be more useful. 2) They can be efficiently decentralized, which benefits reliability, and decreases transmission loss. But anyway, the solution is to use any and all technolog…

Batteries have a variety of uses on the grid. If you're clever enough to use them for several of these at the same time, it makes it easier to pay their way:

http://www.rmi.org/electricity_battery_value

Re: How cheap does solar power need to get before it takes over the world?

#102

Post by eru »

jimrandomh wrote: post #37
eru wrote: post #22

Earlier quoted context omitted.

Manufacturers will sell as expensive as they can get away with. Of course, there's decent competition in this market to counteract that. jimrandomh's scheme would require a significant amount of collusion between all major producers.

No, it's just that building a solar-panel factory is really expensive and has a longer lead time than customers will wait.

Isn't that the same with almost any kind of factory? If I was in the market for a car or computer, I wouldn't want to wait for a new factory to be build, either.

Is that anything special about the solar-panel industry?

Re: How cheap does solar power need to get before it takes over the world?

#103

Post by eru »

imaginenore wrote: post #76
marvin wrote: post #64

Earlier quoted context omitted.

Did you compensate for cost in this example?

Cost has nothing to do with this argument. He is talking about energy density.

I was talking about cost. I don't know about p1mrx.

In any case, a bit of Googling will give you more details about the improvements than my faulty memory..

Re: How cheap does solar power need to get before it takes over the world?

#104

Post by erikpukinskis »

amazon_not wrote: post #74
erikpukinskis wrote: post #36

Earlier quoted context omitted.

Batteries have some advantages that can offset the cost a little: 1) You can move them around, as in an electric car. That's useful if you want to do mobile stuff like driving. Or if you just flat-out want to move the facility somewhere it will be more useful. 2) They can be efficiently decentralized, which benefits reliability, and decreases transmission loss. But anyway, the solution is to use any and all technolog…

> Or if you just flat-out want to move the facility somewhere it will be more useful. While an interesting theory, I can't think of a single scenario where this would be economically justified. > 2) They can be efficiently decentralized, which benefits reliability, and decreases transmission loss. Transmission losses are about 6%, so not really any economic gain.

Wouldn't that be a 6% economic gain?

Re: How cheap does solar power need to get before it takes over the world?

#105

Post by amazon_not »

erikpukinskis wrote: post #104
amazon_not wrote: post #74

Earlier quoted context omitted.

> Or if you just flat-out want to move the facility somewhere it will be more useful. While an interesting theory, I can't think of a single scenario where this would be economically justified. > 2) They can be efficiently decentralized, which benefits reliability, and decreases transmission loss. Transmission losses are about 6%, so not really any economic gain.

Wouldn't that be a 6% economic gain?

Only if your local generation plus battery system is equivalent or cheaper at providing power than the grid. Most battery systems aren't profitable even if power is free. So, no.

Re: How cheap does solar power need to get before it takes over the world?

#106

Post by dredmorbius »

extrapickles wrote: post #96
dredmorbius wrote: post #68

Earlier quoted context omitted.

My understanding is that the grid-scale stuff will be using natural geological reservoirs -- basically re-filling old gas wells with air. My understanding isn't particularly deep, and I'd like to run numbers on storage, volume, pressure, etc. But I suspect this'll have to be big enough that constructing cans really isn't viable.

The main problem in my mind is not where to store the compressed air, but the poor efficiency of compressing/using the air. Compressing air produces quite a bit of heat, and you have the opposite problem when using the air. For Thermal and other storage methods while the storage part might be more lossy, they are less lossy over all because they dont toss away 80% of the power before it can be stored. If it was more…

Realise that virtually all your energy storage options have hugely pressing cost, capacity, or storage stability problems.

Pumped hydro's remarkably efficient, fast-responding (minutes), but extremely limited in scale. See Tom "Do the Math" Murphy, but I think you'd need ~1,500 or was it ~15,000 Hoover-dam sized project for US storage capacity.

Batteries are fairly efficient, but respond slowly (you can neither charge nor discharge them rapidly), and at scale virtually all have massive substrate / materials shortages -- lead and lithium particularly. Iron-based batteries should be abundant, and liquid metal or molten-salt batteries seem to be the most abundant. Storage densities aren't great, but if you're building stationary facilities, that's not a concern. The 600C - 800C temperatures may be though. Having a neighbourhood melt-out wouldn't be pretty.

Biomass might work for standby thermal generation.

Thermal salt storage also pencils out. But any thermal storage system, that is, hot stuff you use to boil a working fluid that runs through a gas turbine, suffers from Carnot efficiency losses, about 35-45 max efficiency. If in a desert area, you've got problems of cooling your working fluid without venting too much of it (or the coolant). Not insoluble problems, but an issue.

Heat also doesn't store indefinitely though it should be good for hours to a few days.

Fuel synthesis has the advantage of scaling fairly arbitrarily large, particularly with liquid hydrocarbons. Put them in liquid-proof tanks and they'll stay there. Storage stability is proven to 100s of millions of years, so there's that. They're also transportable and can be utilised on-site. You lose 50% in hydrogen electrolysis, plus 65% on Carnot, for a net return of about 17%, but if you've sufficient peak surplus, that's viable.

CAES has the hot/cold problem, but there's a lot of air, and there's a lot of underground reservoir. Again I'm not sold that it pencils out, but it's possible.

Other options include direct banking of heat for buildings and/or industrial processes -- these use a lot of energy, and direct application and storage avoids electric or electric-to-fuel conversion losses.

It'll be interesting.

Re: How cheap does solar power need to get before it takes over the world?

#107

Post by dredmorbius »

ThrustVectoring wrote: post #97
pdonis wrote: post #32

Earlier quoted context omitted.

> For solar to affect petroleum, whose primary use is transport, we'll need to solve the storage problem. The obvious solution here is solar-generated biofuel, such as the algae projects now being investigated.

That's not necessarily the correct solution - there's competing chemical processes like Fischer-Tropsch.

Once you've got electricity, FT appears to win. Though again, there's the ages of investigation without large-scale application, on a power-to-fuels basis.

Sasol, the South African energy company, did run commercial coal-to-liquids via Fischer-Tropsch, since the 1950s, and I believe may still do so. The US tried but ran into technical issues.

Re: How cheap does solar power need to get before it takes over the world?

#108

Post by ZeroGravitas »

martinald wrote: post #11

I think the issue is that OK, say we managed to get to 100% electricity being solar when the sun is shining. You'd still have the time the sun is not shining, which would likely be more expensive than before (a gas powered plant would only be running half the time - effectively doubling its capital/construction cost per kWh). So you'd definitely have an improvement on some levels but I'm not sure that would really he…

Lots of gas plants already run only a fraction of the time. This is because demand goes up and down on both a short and long term basis e.g. in many places the peak daily demand is just after lunchtime, and peak yearly demand is mid-summer, with an absolute peak at noon on one summer day. Without grid scale storage demand must be matched, hence ridiculously expensive gas peaker plants and transmission lines built for these peak loads.

It is in fact these very expensive gas plants that solar is destroying the market for first, both because they are the most expensive to run, but also because solar happens to align with the natural peaks in demand.

Re: How cheap does solar power need to get before it takes over the world?

#109

Post by eru »

p1mrx wrote: post #53
eru wrote: post #19

Earlier quoted context omitted.

> The real big breakthrough would be somme big improvement on storage. I'm not convinced this will happen quickly (at least not in anyway similar to the declining cost of PV panels). The consumer electronics industry has been paying $$$ for decades for better batteries/battery r&d and has seen pretty poor gains. Actually, it's not too bad, just slower. Batteries improve around 8% per year, if I remember right. That's…

Li-ion 18650 cells held 2300mAh in 2005[1], and 3350mAh today[2]. That's an increase of 45% in just under 11 years. If capacity were really growing at 8% per year, then 18650 cells should have a capacity of 5300mAh by now. [1] http://www.candlepowerforums.com/vb/showthread.php?88468-Tri... [2] http://www.candlepowerforums.com/vb/showthread.php?417736-Te...

Oh, it's not just one technology getting the increase, but switching to other technologies over time.

Thanks for digging up the numbers!

Re: How cheap does solar power need to get before it takes over the world?

#110

Post by ZeroGravitas »

icefox wrote: post #24
martinald wrote: post #11

I think the issue is that OK, say we managed to get to 100% electricity being solar when the sun is shining. You'd still have the time the sun is not shining, which would likely be more expensive than before (a gas powered plant would only be running half the time - effectively doubling its capital/construction cost per kWh). So you'd definitely have an improvement on some levels but I'm not sure that would really he…

Of course if the more solar we get combined with cheap computing a market will emerge where there are two prices of electricity. Car charging will probably be first where they turn on/off depending on the solar output. Refrigerators and AC could follow.

You can already charge your EV for less if you let the utility modulate the charge rate to match their demand/supply.

http://www.emotorwerks.com/index.php/component/rsform/form/1...

In areas where the utility is not set up to do this, you can programming it to monitor the grid and prefer charging when the grid is less carbon intensive.

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