How cheap does solar power need to get before it takes over the world? • Hacker News Board

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

#91

Post by Someone » Tue, Apr 19, 2016, 3:33 PM UTC

dredmorbius wrote: post #34

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…

No idea why the hivemind is downvoting you, but you're absolutely correct. A couple of additions and caveats. Friend of mine at ORNL has been talking up compressed air energy storage (CAES). I'm somewhat dubious due to the Boyles law heating/cooling problem (gasses heat when compressed, cool when expanded, and the resulting heat flows affect both efficiency and equipment function -- gas turbines don't spin well when…

"Being able to use oceans as a lower baisin might address this"

There also are ideas to use the ocean as the higher basin. See https://trustyetverify.wordpress.com/2014/12/11/energy-from-..., https://www.technologyreview.com/s/510806/a-manmade-island-t...

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

#92

Post by dredmorbius » Tue, Apr 19, 2016, 3:50 PM UTC

evgen wrote: post #72

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.

Doesn't this run into insulating problems for the resevoir? How do you prevent the pressure from being lost as heat?

Rock is a pretty good insulator.

Anythhing exposed to fluid isn't. Groundwater flws, tanks in air.

I'm not sure about possible ignition explosion risk from residual methaane or hyrogen, say.

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

#93

Post by dredmorbius » Tue, Apr 19, 2016, 3:51 PM UTC

Someone wrote: post #91

dredmorbius wrote: post #34

Earlier quoted context omitted.

No idea why the hivemind is downvoting you, but you're absolutely correct. A couple of additions and caveats. Friend of mine at ORNL has been talking up compressed air energy storage (CAES). I'm somewhat dubious due to the Boyles law heating/cooling problem (gasses heat when compressed, cool when expanded, and the resulting heat flows affect both efficiency and equipment function -- gas turbines don't spin well when…

"Being able to use oceans as a lower baisin might address this" There also are ideas to use the ocean as the higher basin. See https://trustyetverify.wordpress.com/2014/12/11/energy-from-... , https://www.technologyreview.com/s/510806/a-manmade-island-t...

Interesting. Japan's done a lower baisin trial.

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

#94

Post by dredmorbius » Tue, Apr 19, 2016, 3:59 PM UTC

jasonwatkinspdx wrote: post #90

dredmorbius wrote: post #34

Earlier quoted context omitted.

No idea why the hivemind is downvoting you, but you're absolutely correct. A couple of additions and caveats. Friend of mine at ORNL has been talking up compressed air energy storage (CAES). I'm somewhat dubious due to the Boyles law heating/cooling problem (gasses heat when compressed, cool when expanded, and the resulting heat flows affect both efficiency and equipment function -- gas turbines don't spin well when…

> Carbon source from seawater appears somewhat promising, though my concern is that there's been 50 years of research without a large-scale demonstration project, making me suspect deeper issues. I haven't seen anything about it recently, but the Navy was/is funding a demonstration plant in Hawaii. I really hope it works out as I'm skeptical that the developing world will shift to electric vehicles anytime soon.

History & paper to 1964: https://www.reddit.com/r/dredmorbius/comments/28nqoz/electri...

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

#95

Post by dredmorbius » Tue, Apr 19, 2016, 4:02 PM UTC

pdonis wrote: post #32

dredmorbius wrote: post #30

Earlier quoted context omitted.

Solar doesn't much compete with petroleum. Its main effect is to reduce prices for coal. You'd expect that this might start to affect the profitability of coal companies eventualy.... For solar to affect petroleum , whose primary use is transport , we'll need to solve the storage problem. Tesla notwithstanding that has not happened. Electric vehicle sales were 0.66% of unit auto sales in 2015, and actually represente…

> 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.

HANNP is still your limiting factor. Algae offers at best about 1,000 gallons/acre/yr. That's good, but small relative to utilisation.

https://www.reddit.com/r/dredmorbius/comments/2cvap7/the_int...

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

#96

Post by extrapickles » Tue, Apr 19, 2016, 4:09 PM UTC

dredmorbius wrote: post #68

extrapickles wrote: post #57

Earlier quoted context omitted.

Compressed air storage rings of a scam to me. They never mention how efficient it is to compress the air and turn the air back into electricity. It's always how efficient their storage tank is, which on paper gives batteries a run for their money. When sizing an industrial air system a rule of thumb is to budget 7-8hp of compressor for 1 hp of air motor. That is 12% efficiency, or only worth it if you had no other so…

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 efficient, than we would see air powered cars (not the scam that surfaces every other year).

Industry only uses it to power things because you can have simple & compact actuators and high rpm motors.

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

#97

Post by ThrustVectoring » Tue, Apr 19, 2016, 4:22 PM UTC

pdonis wrote: post #32

dredmorbius wrote: post #30

Earlier quoted context omitted.

Solar doesn't much compete with petroleum. Its main effect is to reduce prices for coal. You'd expect that this might start to affect the profitability of coal companies eventualy.... For solar to affect petroleum , whose primary use is transport , we'll need to solve the storage problem. Tesla notwithstanding that has not happened. Electric vehicle sales were 0.66% of unit auto sales in 2015, and actually represente…

> 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.

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

#98

Post by shalmanese » Tue, Apr 19, 2016, 5:09 PM UTC

extrapickles wrote: post #57

artr wrote: post #39

Earlier quoted context omitted.

This is what Danielle Fong at Lightsail has been doing since 2009. They've had investment from Bill Gates and Peter Thiel. They've developed a way to compress and decompress air efficiently by heating/cooling the air. by using a carbon fibre air canister they are able to store air at a much higher pressure than previously possible. Her Ted Talk[1] and their website[2] explains it much better than I do. [1] https://ww…

Compressed air storage rings of a scam to me. They never mention how efficient it is to compress the air and turn the air back into electricity. It's always how efficient their storage tank is, which on paper gives batteries a run for their money. When sizing an industrial air system a rule of thumb is to budget 7-8hp of compressor for 1 hp of air motor. That is 12% efficiency, or only worth it if you had no other so…

There's some secret magic going on using moisture and phase change to drastically up the efficiency and storage capacity. It's not just a simple compressed air system which, as you noted, doesn't work. No idea if their current system will work or not but it's complicated enough that they've spent 7 years trying to get it right.

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

#99

Post by Gravityloss » Tue, Apr 19, 2016, 5:37 PM UTC

Animats wrote: post #8

Installation has to get much cheaper. Installation is now more than the cost of the panels for most single family home installations. Home roofs are poor support surfaces. Panels which are the roof have potential. The "solar shingle" vendors are making progress.[1] [1] http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0944/...

I'm amazed that they aren't integrated much more. Roof materials already have a cost. For example, one could create big roof tiles that are mostly solar panel. Edges have to overlap so it's a good idea to not have the panel extend there. One could lay them like other traditional flat panels, in an overlapping fashion. Since the actual panel is so cheap, that shouldn't bring up the cost of the roof panel much.

The wiring can be on the underside and can be then connected after construction. (By some other team than roof constructors). After 30 years, they can be swapped. There might be some new technology then.

Another alternative would be roll-out plastic panels on ordinary roof materials. External wiring.

Everything should be laughably easy if you don't need to deal with snow and ice. They are a whole new design problem. To best limit CO2 emissions, the manufactured panels should be installed in places with best production ability, so freezing tends not to be among the first problems.

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

#100

Post by Gibbon1 » Tue, Apr 19, 2016, 6:38 PM UTC

spacecowboy_lon wrote: post #75

Gibbon1 wrote: post #12

Earlier quoted context omitted.

If you run the numbers pumped heat storage can likely do the job of time shifting electric power from daylight hours to night time. The pricing structure will flip though, electricity at night costing probably 2-3 times peek daytime rates. One would expect industrial users would adjust and avoid using power at night[1]. That would reduce demand. [1] Think of a mini-mill (steel) that currently runs its electric furnac…

I thought blast furnaces ran 24/7 and if they shut down you need to effectively rebuild parts of them.

You are correct integrated mills use blast furnaces and thus can't stop. However Mini mills are secondary producers. They process scrap into finished steel. Since they use electric furnaces they can start and stop production.