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When Will Rooftop Solar Be Cheaper Than the Grid?

When Will Rooftop Solar Be Cheaper Than the Grid?

Counties where residential solar LCOE reaches parity with local average electric rates at various solar installed costs.
COURTESY OF JOSHUA RHODES/UNIVERSITY OF TEXAS-AUSTIN
http://imgur.com/lkxIbGz

Article: http://www.usnews.com/news/articles/2016-03-31/when-will-rooftop-solar-b...

bb0tin | 27 juin 2016

Thanks for the image.
Once we have long run roofing with thin film solar built in at manufacture, you will not even install solar. You will simply install a roof, just like now. The extra cost will be minimal. The same goes for tiles but it won't be as simple. Is solar cheaper than the grid will be entirely moot.

sp_tesla | 27 juin 2016

"bb0tin | June 27, 2016
Once we have long run roofing with thin film solar built in at manufacture,"

It's being a while since concept was develop, surprising its not available yet.

Mike83 | 27 juin 2016

I just read that 24 % efficiency is now shown in the newest PV's for manufacturing. That is amazing as it was 18% for awhile. that is something like 0.4 hp/meter squared at max sun.
As the manufacturing process improves the costs are becoming cheaper. Soon you may only need 10 panels instead of 25 panels to generate the same amount of energy.
Great news for getting off the fossil fuel addiction.

vp09 | 27 juin 2016

I'm having Sun Power/Sun Solar install a system. It will be 13 panels for almost 5 kWh total. My system on my old house in 2003 was 12 panels for 2.2 kWh. Same cost now as then overall-- $23,000. Twice as much electricity generation. Panels are 360 watts each with the inverters on the backs of the panels. Old ones were Sharp 180 watts with a Sunny Boy inverter next to the main circuit box and electric meter.

Mike83 | 27 juin 2016

Since I want to have battery backup I want to have an inverter for it; not sure if the inverters on the panels are the best. I will have time to check this out.

It is amazing how much more you get for your buck now. I see a huge market developing.

bb0tin | 27 juin 2016

@vp09
If you are getting 5kWh installed for $23,000 you are being ripped off. That is $US4.60 per watt assuming you are in the US.

bb0tin | 27 juin 2016

@Mike83
Microinverters on each panel are the better choice for multiple reasons. The only downside is an initially higher price, but it pays for itself quickly.

ran349 | 27 juin 2016

I don't think $4.60/per watt would be considered a rip off for that sunpower system. Sunpower panels are the best made. Yes, you can get cheaper per watt systems, but you get what you pay for. I think about $3.50/watt is the low end from what I hear.

bb0tin | 27 juin 2016

You can get $US2.99 right now in the US.
As for 'the best', it really comes down to efficiency, cost and warranty. Why pay 50% more for something which gives you no economic advantage?

Manny13z | 27 juin 2016

I just installed a 10.3 kWh system and my payments are lower than my power bill by $100.

rxlawdude | 27 juin 2016

@bb0tin, microinverters have not been proven to last 30 years. When 13 microinverters need to be replaced, that will kill any savings greater efficiency brings. I agree they maximize each panel's output, but they are no panacea. Further, I don't think they are compatible with the PowerWall since it just is a DC battery and relies on the string inverter to make AC. Happy to admit I'm wrong about this last point.

rxlawdude | 27 juin 2016

@bb0tin, microinverters have not been proven to last 30 years. When 13 microinverters need to be replaced, that will kill any savings greater efficiency brings. I agree they maximize each panel's output, but they are no panacea. Further, I don't think they are compatible with the PowerWall since it just is a DC battery and relies on the string inverter to make AC. Happy to admit I'm wrong about this last point.

rxlawdude | 27 juin 2016

Sorry for the duplicates. Darn phone. :-)

bb0tin | 27 juin 2016

@rxlawdude
Microinverters usually have warranties of 10 to 25 years. They are expected to last more than 25 years.
String inverters have as little as 3 year warranties. They are expected to fail in as little as 10 years and need to be replaced.
The current Powerwall does not have a DC-AC inverter. When the SMA inverter is available it may be about $US1100 based on the euro price. I hope that Powerwall2 or Powerwall3 will come with an inbuiilt DC-AC inverter.
There are several advantages that microinverters have over string inverters, and this information is available from the web.

dborn @nsw.au | 28 juin 2016

My Fronius string inverter lasted until just after warranty ran out, naturally. The AC power board has just been replaced. A component burnt out. It does not help that I live on the ocean, but you would think they would have sealed the board. The new board is apparently sealed.

vp09 | 28 juin 2016

bb0tin, I was happy to contract for a system at all. I first tried SolarCity, and they turned me down. I offered to pay cash up front, but no. I wasted a month or so with them. They said it wasn't their decision-- some California regional government agency disallowed it because I didn't have enough sun on my roof. I asked for a ground mounted display, but they said they didn't do that at this time.

I have a home surrounded by big trees. Sycamores, redwoods. That's why I bought the house. But some of the roof is shaded all of the time, except a small part in the middle. Most of the roof is shaded some of the time, except for that middle part.

Sun Solar/SunPower did my neighbor's home, and I contacted that company, telling them that SolarCity had turned me down. Their man was out the next day, and we were standing on my roof, and he showed me the yearly sun cycle on his meter, and said I had 72% sun, and that the lowest they'd installed was on a home with 80%, but I said I'd pay cash and just add some extra panels to make up for the shade. He said okay, but the 13 panels have a smaller footprint than the less efficient ones SolarCity planned, so my new panels will be in the sun most of the time.

The Sun Solar rep, Aaron Dabbs, said he had no idea what agency SolarCity was talking about.

rxlawdude | 28 juin 2016

@bb0tn - As we know, warranty periods are not dispositive of real-life experiences. Again, my point is if a string inverter fails, it's a single component in an accessible area that requires minimal labor.
A single failed microinverter requires disassembly of the panels and the attendant risk of roof damage. Multiply that point of failure by the number of panels.

So you do concur that PowerWall, as it is designed today, is incompatible with a microinverter array. You can "hope" away, but let's focus on what the current realities are.

bb0tin | 28 juin 2016

@rxlawdude
You said "As we know, warranty periods are not dispositive of real-life experiences."
String inverters are expected to fail after about 10 years. That is why they often have only a 3 year warranty. You may therefore need to purchase 3 string inverters within 25 years. Microinverters will still be under warranty so you have only purchased one. String inverters are no longer the best option for multiple reasons. The only reason is a cheaper initial cost, but you are likely to have to replace it at least once within the life of the rest of system.

You said "A single failed microinverter requires disassembly of the panels and the attendant risk of roof damage. "
It is a simple 15-30 minute job. No damage to the roof at all. It will cost $0 if you do it yourself.
It is not cheap or simple to replace a string inverter. It will cost $US1000-$US2000.