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

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

#241

Post by ChuckMcM »

thechao wrote: post #140
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…

Is this DIY, or installed? If it's not DIY, mind passing along who you're using? Inquiring TX minds would like to know!

My wife and I designed the system but it was installed by a Los Gatos company that did not survive. As part of our education efforts, my wife completed a program to become a certified solar installer (you needed to be certified to get the full rebate at the time) but one of the women she met in the class was working at this company and it just made sense to give them the job to help them bootstrapping their company.

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

#242

Post by zsombor »

SEJeff wrote: post #189
kragen wrote: post #163

Earlier quoted context omitted.

I think you're being a little unfair with the S&P comparison: you should be comparing the returns on your actual investment with the expected returns on the S&P, not its actual returns. The stock market got a 5.4% return over that time, yes, but that's above average; we should expect its long-run returns to be close to the rate of economic growth, or more like 3%. And it could easily have been zero or even negative o…

Actually the markets are "supposed" to double every 10 years, which is said that on average over 10 years, the markets will grow 10% per year. Since the recession 8 years ago that has been much lower, but in general, that is the rule most industry people will give you. I work as a tech guy in finance and have for the past 8.5ish years.

For something to double in 10 years it only has to grow by 6.9% per year. This is from a somewhat unusual application of The Rule of 69. Latter is way of determining doubling time of something that grows by x%: just divide 69 by x and that will be the doubling time in periods.

So if the DB grows by 10% weekly, then it will double in 6.9 weeks. If the interest rate is 3% then the debt will double in years, etc.

The Rule of 69 is good for a approximation, that works well with low single digit increases.

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

#243

Post by dragontamer »

ZeroGravitas wrote: post #219
dragontamer wrote: post #162

Earlier quoted context omitted.

> You need to consider the economics of "grid tie" you generate excess power into the grid and "buy it back" when you aren't generating in excess. Depends on the state. Sometimes, you buy at retail prices and sell at wholesale prices. Which honestly, is far more fair. You're basically using the utility's batteries / energy storage at no charge right now (if you're in a state with pure net metering laws) And yes, purc…

"Fair" in the context of a heavily regulated utility should have some relation to social benefit. It's not fair for utilities to force costs onto consumers just because of a differential of political influence. It's not fair that solar reduces grid load at their peaks and saves them money on building out grid capacity and expensive and inefficient CO2 producing gas peaker plants and that benefit is not returned to th…

Consumers should pay a fair price for the service.

If consumers are using the utility's batteries and the utility's network, then the consumer should pay for the use of those services.

Peaker-plants can have a very simple solution: carbon taxes. Simple enough, and I support this measure to handle the externality.

Rooftop solar currently is probably a net benefit as long as the storage issue isn't a problem. (IE: the rest of the neighborhood doesn't have solar). But once solar adoption is widespread, someone needs to solve the storage issue (or "energy waste", if there is no more storage)

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

#244

Post by walrus01 »

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 major challenge now is no longer PV and gridtie inverters, but energy storage. Whether it's batteries, pumped storage hydroelectric, whatever.

$$$ per kWh stored (and the lifetime/cycle life + operating costs of that storage) is a key benchmark.

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

#245

Post by kragen »

coredog64 wrote: post #216
kragen wrote: post #169

Earlier quoted context omitted.

Unless it's dorm-fridge-sized, you can definitely run your refrigerator only during the day, generating ice to cool it during the night. Building HVAC systems often work this way, running the chiller to generate ice during the night (when electricity prices are low or even negative) and running the resulting chilled water through heat-exchanger coils during the day. And superinsulated fridges like Sunfrost models can…

As an EMH guy, I'd like to think that if an Einstein–Szilard cooler was more economical than grid power for A/C and/or food refrigeration that there'd already be systems for sale.

There are absorption refrigerators for sale for food refrigeration — I had one in my Volkswagen — but I don't think they use the Einstein-Szilard design, but a simpler one. Here's one: http://www.amazon.com/Norcold-Inc-Refrigerators-N841-Refrige...

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

#246

Post by kragen »

ChuckMcM wrote: post #239
kragen wrote: post #163

Earlier quoted context omitted.

I think you're being a little unfair with the S&P comparison: you should be comparing the returns on your actual investment with the expected returns on the S&P, not its actual returns. The stock market got a 5.4% return over that time, yes, but that's above average; we should expect its long-run returns to be close to the rate of economic growth, or more like 3%. And it could easily have been zero or even negative o…

True, but its too easy to get lost in financial modeling. There were two high order bits in my decision, first was that the money was spent either way; Either I would be paying PG&E month to month, or I'd be paying off the system. And there was a good shot that the panels would generate as much or more energy for that investment. The second was that I felt it was the right thing to do, not a lot of people were in a p…

Just to be clear, I think it was a decent investment then (better than the stock market) and an excellent one now. I'm not one of the folks trying to show something negative about solar power.

I find your belief inspiring.

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

#247

Post by pc2g4d »

mjevans wrote: post #237
S_A_P wrote: post #229

Earlier quoted context omitted.

Can validate. The problem with electricity is that there is no large scale storage like there is for other forms of energy like NG and Crude. Until someone comes along and figures out how to store electricity, this will continue to cause grief to power companies. Power plants are really just options, if the price per kWh is at a certain point then it makes sense to spin up or take down a plant and generate power. Add…

We have a lot of good technologies already, the problem is they just don't scale well. I can envision older warehouses in an industrial district being converted in to vacuum flywheel storage sites where power fed in to the grid earlier is buffered and then released back to it. Changing our culture is another possible approach. Power is used in the evenings because that's when most people get off work/home/etc and the…

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

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

#248

Post by azernik »

ams6110 wrote: post #186
peppaz wrote: post #102

Earlier quoted context omitted.

Good thing Tesla is making huge battery packs for our homes so we can ditch the grid entirely.

I think it will never be the case that you can run a household solar/battery plant for less than a utility can do it on massive scale and just run a wire to your house (remember to factor in depreciation on all your household kit, batteries and inverters don't last forever).

I think this applies more on the battery side than the solar side. There are certain options for storage that are totally impractical for home use. For example, vanadium redox batteries [1] are so bulky that you probably don't want to put them in expensive residential real estate, but they're pretty cheap and effective.

But a mix of residential solar and utility-managed batteries could be viable; it's not clear to me that the economies of scale for large solar installations are very strong.

[1] https://en.wikipedia.org/wiki/Vanadium_redox_battery

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

#249

Post by criddell »

dragontamer wrote: post #171
criddell wrote: post #165

Earlier quoted context omitted.

> And during the day, when you have peak-solar energy, you'll be at work and won't be taking advantage of it. I'm in Central Texas and I have two dogs at home. Even if I'm not there, I still leave the air condition going so they are comfortable. The last time I checked, my A/C system was the biggest power hog and so my electricity consumption aligns very closely with when the sun is shining.

Biggest power hog? Yes. But not the only thing. My point is that its way too idealistic to assume that 100% of the costs will be covered. I mean, yes, the laws as written seem to encourage a 1-to-1 transmission of energy. "Net Metering" is a law that subsidizes decentralized solar energy. But in the future, when the subsidies run out and the laws are written to be FAIR (instead of written to encourage solar, as they…

I'm not sure what you mean by 100% of the costs will be covered. All I know is that I can reduce the amount of electricity that I buy during the day when I consume the most. The savings are greater than the cost so it's pretty much a no-brainer for me at this point. If I finance, I can pretty pay for the system with the money that I'm no longer using to buy electricity.

> when the subsidies run out

Why stop subsidizing solar? Do you think all energy subsidies are going away, or just solar?

https://en.wikipedia.org/wiki/Energy_subsidies#Allocation_of...

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