The price of solar power just fell 50% in 16 months • Hacker News Board

Re: The price of solar power just fell 50% in 16 months

#301

Post by Animats » Tue, May 03, 2016, 9:43 PM UTC

It's time to get most air conditioning load onto solar. In the US, areas south of 37° (central California across to everything south of Virginia) should have enough local solar power to drive daytime air conditioning. For that, we don't need storage, we don't need to feed much power back into the grid, and air conditioning is the big residential load. 21% of electricity consumption in the South is for air conditioning. This is a no-brainer right now.

Here's an application for "smart power" technology. When a cloud comes over and blocks the sun, air conditioner compressors should shut down temporarily. If the cloud cover remains, start up again, on a somewhat random time delay, to give generators time to respond. (This will probably be implemented with some overly complex system that involves "the cloud", rather than being done by a simple broadcast signal.)

Re: The price of solar power just fell 50% in 16 months

#302

Post by daveheq » Tue, May 03, 2016, 9:45 PM UTC

coryfklein wrote: post #215

ChuckMcM wrote: post #103

The aggressiveness of the price drops on solar is pretty amazing. I just lost one of the inverters on my grid-tie system after it had run trouble free for 13 years. So we're looking at the first "major" repair to the system I installed in 2003. And in 2003 my 5.2kW of panels on my roof cost $38,000 before subsidies and $19,000 after. 28 panels, two 2.5kW inverters, net about 4.2kW of generation. I priced out replacin…

> And that is why it is a huge problem for the power companies It is a problem, but not necessarily in the way you may be thinking. Peak residential power usage is in the evening when solar isn't available. Power companies therefore end up spinning down coal and natural gas during peak solar, then just spinning them back up again as the sun begins to set. [1] So you haven't replaced the coal and natural gas plants, y…

The power companies can get overflow from solar and wind and water and redistribute it at a profit while paying the residential over suppliers. It's on the power companies to build the infrastructure like batteries to take advantage of all this free new power.

Re: The price of solar power just fell 50% in 16 months

#303

Post by lisivka » Tue, May 03, 2016, 9:49 PM UTC

dragontamer wrote: post #138

krschultz wrote: post #111

Earlier quoted context omitted.

Payback of 6 years with the new cost, even for your low electric bill.

Unlikely. Solar Panels don't replace all of your electricity costs. Naturally, you'll still run your refrigerator at night, right? And during the day, when you have peak-solar energy, you'll be at work and won't be taking advantage of it. You'll recoup some of the costs through net-metering, but you usually buy back at wholesale prices and not at retail prices. Finally, I'd expect utility companies to change their pr…

If you have space and money, you can create huge "gravity lamp" to store energy: lift up something massive using solar energy and electric motor, then it will slowly generate electricity at night using same motor as generator.

Or you can use "molecular spring", which is very compact, for same purpose.

Re: The price of solar power just fell 50% in 16 months

#304

Post by [deleted] » Tue, May 03, 2016, 9:49 PM UTC

daveheq wrote: post #302

coryfklein wrote: post #215

Earlier quoted context omitted.

> And that is why it is a huge problem for the power companies It is a problem, but not necessarily in the way you may be thinking. Peak residential power usage is in the evening when solar isn't available. Power companies therefore end up spinning down coal and natural gas during peak solar, then just spinning them back up again as the sun begins to set. [1] So you haven't replaced the coal and natural gas plants, y…

The power companies can get overflow from solar and wind and water and redistribute it at a profit while paying the residential over suppliers. It's on the power companies to build the infrastructure like batteries to take advantage of all this free new power.

[deleted]

Re: The price of solar power just fell 50% in 16 months

#305

Post by teraflop » Tue, May 03, 2016, 9:53 PM UTC

flo-g wrote: post #299

jackcosgrove wrote: post #233

Earlier quoted context omitted.

I would propose a global power grid as a solution to this problem, on which the sun would never set. The only problem is that earth is not set up well for this: the Sahara would be the solar workhorse of the planet, and the consumer of all this power would be Hawaii.

What if the grid connects (residential and commercial) across time zones, one generating for the next with no need of storage devices?

Maybe if we had room-temperature superconductors. For now, transporting huge amounts of electric power across many thousands of miles is very, very inefficient.

Re: The price of solar power just fell 50% in 16 months

#306

Post by toomuchtodo » Tue, May 03, 2016, 9:55 PM UTC

maxerickson wrote: post #217

toomuchtodo wrote: post #156

Earlier quoted context omitted.

> In many cases solar is really close to a no brainier. Which is why Florida Utility's have tried so hard to block residential adoption. This is actually turning into a hollow victory for Florida utilities. To bring people up to speed, Florida outlawed homeowner PPAs [1] (which locks out firms like Solar City, who install the panels and sell you power; no out of pocket cost for you, and you get solar immediately). Wi…

The accelerating payments in the PPAs might not be so great if electric prices drop due to solar (in the example below they go up 2.9% per year). https://www.solarcity.com/sites/default/files/sc-contract-re... Being responsible for the full 20 year term is also a somewhat onerous financial agreement.

> Being responsible for the full 20 year term is also a somewhat onerous financial agreement.

I don't think so. Is it wrong to be responsible for a car when you lease it? Different asset, different terms.

Re: The price of solar power just fell 50% in 16 months

#307

Post by toomuchtodo » Tue, May 03, 2016, 9:56 PM UTC

Someone wrote: post #203

antisthenes wrote: post #159

Earlier quoted context omitted.

While that is true, keep in mind that future dollars are less expensive than present dollars. But it stands to reason that the prices of energy will rise faster than the rates of inflation, so it would still be a good investment.

If everybody buys solar, electricity prices will only rise faster than inflation in periods without much sun. It might even be profitable to play a 'buy when it is free or cheaper, use when it costs money' strategy. You can get there by buying large batteries, charging them from your neighbor's solar panels when there is lots and lots of sun (they may even sell at prices below zero), and discharging them, selling to…

I'm already investigating buying 50+ MW at a time of Tesla Powerpacks in certain markets exactly for this purpose, as an independent generator. Buy power when people are paying you to take it, releasing it back to the grid at the most expensive times.

Re: The price of solar power just fell 50% in 16 months

#308

Post by epistasis » Tue, May 03, 2016, 10:00 PM UTC

ssmoot wrote: post #294

jobu wrote: post #262

Earlier quoted context omitted.

> When storing a kWh costs $0.10, and there's also adaptive pricing to match supply and demand better, these problems will melt away. If the math and assumptions in this article are correct, then that's exactly the (wholesale) price point Tesla is aiming for with the Powerwall: http://cleantechnica.com/2015/05/09/tesla-powerwall-powerblo... There are a couple other (not yet released) energy storage solutions mentione…

It'd take over 1 BILLION Powerwalls to store half the daily usage in the US (using old usage numbers off Wikipedia). I wonder if there's enough raw materials to make that realistic. And how to you manage recycling, repair, replacement, end-of-life concerns for all those batteries on that scale? Not asking a sarcastic hypothetical. Genuinely curious. It's hard to wrap my head around numbers that big. For reference I u…

Just throwing around "BILLION" doesn't make it seem big, you need to compare it the unit size.

A single gigafactory is going to produce 35 GWh in a year, which is about 5.3 million power walls a year. If their lifespan is 10 years, than we need to produce 1e9 power walls / 10 years = 100 million powerwalls/year to maintain that capacity.

So we'd only need 20 gigafactories worth to do this. And with wind and proper grid interconnects we won't even really need much storage at all to keep the electricity going; the national weather is very very consistent.

We will need enough lithium for our ~300 million cars and their batteries, which are probably going to be 50-100kWh each, which is far far more than storing half a days worth of electricity.

Re: The price of solar power just fell 50% in 16 months

#309

Post by yongjik » Tue, May 03, 2016, 10:03 PM UTC

derefr wrote: post #275

pc2g4d wrote: post #247

Earlier quoted context omitted.

Price electricity differently through the day according to its scarcity and people might eventually adjust their routines to reduce evening usage.

That seems backwards. The aggregate preferences and habits of humans should be seen as an incentivizing force for the creations of new technologies, not the other way around.

Well, in that case, pricing electricity differently through the day will encourage people to develop new technologies for cheaply generating and/or storing electricity for evening consumption peak.

Re: The price of solar power just fell 50% in 16 months

#310

Post by maxerickson » Tue, May 03, 2016, 10:04 PM UTC

toomuchtodo wrote: post #306

maxerickson wrote: post #217

Earlier quoted context omitted.

The accelerating payments in the PPAs might not be so great if electric prices drop due to solar (in the example below they go up 2.9% per year). https://www.solarcity.com/sites/default/files/sc-contract-re... Being responsible for the full 20 year term is also a somewhat onerous financial agreement.

> Being responsible for the full 20 year term is also a somewhat onerous financial agreement. I don't think so. Is it wrong to be responsible for a car when you lease it? Different asset, different terms.

A car is usually a much shorter lease with much better liquidity. There is a robust market for transferring a vehicle lease, the PPA is as likely to derail a sale of the house as anything else.