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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?

#51

Post by rm445 »

Gustomaximus wrote: post #48
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…

Similar to pumped water storage I wonder if we could do a household version with weight. Something like the gravity light (gravitylight.org) but on larger scale. I wonder if we could see a resurgence of chimneys on houses except now instead of letting smoke out they contain a XY ton weights that gets pushed up by excess solar capacity during the day, and then drops by evening powering the house. I have no idea if tha…

The potential energy of a mass m at height h is mgh.

Play with this and you'll immediately see it doesn't seem useful. e.g. storing a 50-tonne weight at 10m gives you less than 1.5 kWh of energy.

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

#52

Post by ScottBurson »

alok-g wrote: post #40

>> 25 cents per watt by 2050 — down from around $3 per watt today Can I trust a report that does not even have the units right?! Price should be proportional to energy (i.e., Joules or Watt-seconds) not power (Watts).

You're mistaken. Fuel is sold by price/energy, effectively, but generating capacity is sold by price/power. Since in the case of solar PV, the "fuel" is free, the only cost worth mentioning is the capacity cost.

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

#53

Post by p1mrx »

eru wrote: post #19
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…

> 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...

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

#54

Post by mgnacl »

Spooky23 wrote: post #25

A: It needs to get efficient enough and paired with storage to survive the regulatory kickback. Power companies and non-solar ratepayers will get increasingly unhappy with net metering customers. That joyride will end.

Next up: taxes on solar cells?

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

#55

Post by gozur88 »

alok-g wrote: post #40

>> 25 cents per watt by 2050 — down from around $3 per watt today Can I trust a report that does not even have the units right?! Price should be proportional to energy (i.e., Joules or Watt-seconds) not power (Watts).

Installed capacity is normally measured in watts. It's really only valuable for trending within the same technology, though, unless you include the capacity factor.

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

#56

Post by tonyedgecombe »

ISL wrote: post #44
eru wrote: post #21

Earlier quoted context omitted.

Pumped water storage is awesome where you have the geography to support it. Alas, that's not everywhere.

Furthermore, mountains, canyons, and valleys are beautiful and valuable as they are.

That hasn't stopped us digging them up for coal though.

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

#57

Post by extrapickles »

artr wrote: post #39
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…

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 source of power. I'll give them the benefit of the doubt and assume a tightly integrated system you could do 3x better, but it still doesn't come close to batteries.

If someone has plug-plug numbers that are better, let me know.

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

#58

Post by Gustomaximus »

rm445 wrote: post #51
Gustomaximus wrote: post #48

Earlier quoted context omitted.

Similar to pumped water storage I wonder if we could do a household version with weight. Something like the gravity light (gravitylight.org) but on larger scale. I wonder if we could see a resurgence of chimneys on houses except now instead of letting smoke out they contain a XY ton weights that gets pushed up by excess solar capacity during the day, and then drops by evening powering the house. I have no idea if tha…

The potential energy of a mass m at height h is mgh . Play with this and you'll immediately see it doesn't seem useful. e.g. storing a 50-tonne weight at 10m gives you less than 1.5 kWh of energy.

So probably needs in excess of 750 ton. And more likely twice as a house would more likely have a 5m 'chimney'. Clearly not viable. Thanks.

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

#59

Post by Qantourisc »

laurencerowe wrote: post #29
icefox wrote: post #24

Earlier quoted context omitted.

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.

In the UK we have Economy 7 which offers lower rates at night. https://en.wikipedia.org/wiki/Economy_7 . It's generally used in homes with 'storage heaters' which heat up overnight and release heat during the day while you're out at work. https://en.wikipedia.org/wiki/Storage_heater

I think we are more talking about hourly prices. You should take a look at the electric market, prices fluctuate heavy. So heavy even in some countries, that you are PAYING when you put electricity on the net: http://www.elia.be/nl/grid-data/balancing/onevenwichtsprijs

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

#60

Post by swombat »

Gustomaximus wrote: post #48
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…

Similar to pumped water storage I wonder if we could do a household version with weight. Something like the gravity light (gravitylight.org) but on larger scale. I wonder if we could see a resurgence of chimneys on houses except now instead of letting smoke out they contain a XY ton weights that gets pushed up by excess solar capacity during the day, and then drops by evening powering the house. I have no idea if tha…

A much better and denser option for storing energy mechanically is flywheels. I haven't researched what happened to this option since but when I was looking into it 15 years ago it seemed like a good option that needed more R&D into frictionless axles and vacuum chambers.
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