Request for input on solar proposal - Q Cells and Enphase Microinverters

[Norseman 2]

I have a 5.5kW Enphase microinverter equipped system that is 7+ years old. Last year half of the microinverters quit for no apparent reason and Enphase agreed to replace them after some investigation. Their local installer completed the job all good. The rub was the significant difference between Enphase allowance for installation and the actual cost which I was invoiced less the Enphase contribution.
I think Enphase figure the time to replace microinverters by doing the job on a bench in a workshop. Pay close attention the the layout of your installation as access to replace microinverters is critical. In our case we had to remove about 20 panels to access all the failed units and provide scaffolding for access as the panels had been installed very close to the edge of the roof leaving no way to access the fittings other than to remove all the panels from the top or to scaffold.
Small issue you will loose all the detailed data from your system unless you back it up for each micro inverter which is replaced although the total power production and use figures remain. It took about 5 months from the failure until the system was fully operational again 3 months of this was due to the local representative being very busy and the people who did the original installation went out of business some years ago so I guess I as not number one priority.
I have to say that the remainder of the Enphase microinverters kept working throughout this period so yes there is that aspect of redundancy in the system. Unless you have significant shading issues I would probably go for a conventional inverter or even two inverters in parallel on separate strings of panels if you are concerned about redundant capacity.

[Cshama]

Like I said I paid $2/ watt. After rebates it was $22k for a 18.36kw system. I have no shading and I produce around $5-6k of electricity a year. My roof is new and I’m hoping to stay here a while. Coned charges around 20 cents a watt- one of the highest rates in the US. I also have full net metering.

Even with all these positives and a 4 year payback I consider my system just barely making sense.

The much better investment was insulation which cut my electricity use by half for a couple of grand and also cutting back on using my hot tub in the winter.

The other bids I had were $50-$60k which I considered ridiculous. And Tesla is abysmal but slightly cheaper.

[nerdralph]

I'd suggest $2/STC W installed cost after rebates/incentives in most of the U.S. is probably not attainable at this time.
Where it is - or may be available for cheap - the solar resource is usually not as available - places like the NE U.S - or is heavily subsidized - or both.

Here in Eastern Canada I'm doing residential rooftop systems for under $2/W before any rebates (about US 160c/W). Despite rising PV panel costs, I've still been able to find good deals, as low as CAD 39c/W for LONGi LR4-72 panels including delivery.

[J.P.M.]

Here in Eastern Canada I'm doing residential rooftop systems for under $2/W before any rebates (about US 160c/W). Despite rising PV panel costs, I've still been able to find good deals, as low as CAD 39c/W for LONGi LR4-72 panels including delivery.

As usual, I'm confused.
1.) At < $ 2W(U.S.) less a $1.60/W (U.S.) rebate form somewhere, you're at $0.40 net (U.S.) per installed STC W.
2.) If you're an installer what do you charge your customers per installed STC W ?
3.) If you're talking DIY, what value do you put on your labor ?
4.) What's a kWh of energy cost from the POCO (hydro) in your parts ?

[nerdralph]

As usual, I'm confused.
1.) At < $ 2W(U.S.) less a $1.60/W (U.S.) rebate form somewhere, you're at $0.40 net (U.S.) per installed STC W.
2.) If you're an installer what do you charge your customers per installed STC W ?
3.) If you're talking DIY, what value do you put on your labor ?
4.) What's a kWh of energy cost from the POCO (hydro) in your parts ?

1 US dollar = C$1.24, so C$2 is about US$1.60. I've never quoted more than C$10,000 for a 5kW system installed on a residential roof. Those prices are before any subsidies, and before sales taxes. I primarily install string systems and avoid MLPE as much as possible. I was using Solis inverters, but I may switch to Growatt's new hybrid inverters if my testing on a 6000TL-HX-US goes well.

Solar subsidy programs have changed frequently since they first became available a few years ago. Currently there is $1/W available under the Greener Homes program, to a maximum of C$5000, or 60c/W from the province to a maximum of C$6000. The two subsidies cannot be combined on the same system, but they could be used for two different systems such as on a house and garage.

Local energy costs are close to the highest in Canada at 17c/kWh including GST. Nova Scotia has full net metering, so it is one of the better provinces for PV despite having relatively low insolation (around the same as most of the New England states). A typical system will produce 1100kWh/yr/kWp.

http://solarns.ca/sites/solarns.ca/files/2018-10/NS_Solar_Price_report_2018.pdf

[J.P.M.]

1 US dollar = C$1.24, so C$2 is about US$1.60. I've never quoted more than C$10,000 for a 5kW system installed on a residential roof. Those prices are before any subsidies, and before sales taxes. I primarily install string systems and avoid MLPE as much as possible. I was using Solis inverters, but I may switch to Growatt's new hybrid inverters if my testing on a 6000TL-HX-US goes well.

Solar subsidy programs have changed frequently since they first became available a few years ago. Currently there is $1/W available under the Greener Homes program, to a maximum of C$5000, or 60c/W from the province to a maximum of C$6000. The two subsidies cannot be combined on the same system, but they could be used for two different systems such as on a house and garage.

Local energy costs are close to the highest in Canada at 17c/kWh including GST. Nova Scotia has full net metering, so it is one of the better provinces for PV despite having relatively low insolation (around the same as most of the New England states). A typical system will produce 1100kWh/yr/kWp.

http://solarns.ca/sites/solarns.ca/files/2018-10/NS_Solar_Price_report_2018.pdf

My confusion was that I took the antecedent subject to your "about US 160c/W" from your post as being the amount of subsidy per STC W, not your installed price per/STC W in U.S. D.

Thank you for the other information.
Compared to some places in the U.S, your rates seem cheap especially taking the exchange rate into consideration.
Too bad about the gouge and screw tax - I hear a lot about that from my many Canadian friends who visit me in So. CA in the winter - but take some solace in the idea that your health care is a whole lot cheaper.

[nerdralph]

Compared to some places in the U.S, your rates seem cheap especially taking the exchange rate into consideration.
Too bad about the gouge and screw tax - I hear a lot about that from my many Canadian friends who visit me in So. CA in the winter - but take some solace in the idea that your health care is a whole lot cheaper.

Alberta actually has lower sales taxes (5% total) than a lot of US state and local sales taxes. In Nova Scotia I think it's higher than anywhere in the US at 15%. But for solar we don't have the 25% duties on Chinese imports. The US-based Solis rep I spoke to told me the $895(CAD) wholesale price I pay for a 1P6K-4G-US from Guillevin-Greentech is less than their landed import cost from China after the duties are added.

[ajonestx]

Realize that microinverters will not last the 25 years they are warrantied for. The manufacturers do this warranty as a ploy to match the 25 year warranty of the PV panels (which will last 50 years) They will replace the microinverters under warranty but you need to be clear about who is going to do the replacement as that is not covered under warranty. Enphase already offered a couple years ago to replace all their early generation product for free - so you can figure how good their reliability promises are....

do you know how SunPower processes warranty claims?

[Will792]

Realize that microinverters will not last the 25 years they are warrantied for. The manufacturers do this warranty as a ploy to match the 25 year warranty of the PV panels (which will last 50 years) They will replace the microinverters under warranty but you need to be clear about who is going to do the replacement as that is not covered under warranty. Enphase already offered a couple years ago to replace all their early generation product for free - so you can figure how good their reliability promises are....

I do not agree with this opinion. It is a fact that many conventional inverters would not last 25 years but most Enphase microinverters will stay functional for 25 years based on modeled MTBF and components they use. At the same time Enphase no longer pays replacement labor fee, when failed units are replaced. I think it used to be $70 for each replaced unit.

Models starting from M215 have been extremely reliable. I would be more worried about SE power optimizers.

[nerdralph]

Models starting from M215 have been extremely reliable. I would be more worried about SE power optimizers.

That's a false dichotomy. I think the most reliable option is a string inverter. Even in jurisdictions that require module-level rapid shutdown, something like the RSD-S-PLC is a simple and low parts count module compared to optimizers or microinverters.

[J.P.M.]

That's a false dichotomy. I think the most reliable option is a string inverter. Even in jurisdictions that require module-level rapid shutdown, something like the RSD-S-PLC is a simple and low parts count module compared to optimizers or microinverters.

FWIW, +1. fewer parts, less stressful environment, KISS applies.

[Mike90250]

I do not agree with this opinion. It is a fact that many conventional inverters would not last 25 years but most Enphase microinverters will stay functional for 25 years based on modeled MTBF and components they use. At the same time Enphase no longer pays replacement labor fee, when failed units are replaced. I think it used to be $70 for each replaced unit.
Models starting from M215 have been extremely reliable. I would be more worried about SE power optimizers.

I don't buy your statement
One, I did MTBF failures for spacecraft for +30 years. I highly doubt any roof top microinverters will be functional after 25 years. Using the VERY BEST space certified gear, it's difficult to get more than 15 years at operational specs. Things may continue to work but in a degraded condition. Power handling equipment is ever less reliable. And I can play in SPICE and make nearly anything come up at 25 years. I honestly suspect they "fudged it" to get 25 years.
Space environment is actually much more controlled with all the thermal control on the spacecraft buss, but roof tops can go from below freezing to over 140F daily

Two. And why did they discontinue replacement labor fee ? I mean if they are good for 25 years, they'd never pay out a nickel !

[Will792]

Two. And why did they discontinue replacement labor fee ? I mean if they are good for 25 years, they'd never pay out a nickel !

Some failures would always happen, no matter what. Enphase eliminated labor reimbursement for replaced microinverters when the company was in danger of folding. It did make sense since nobody else had the same policy.

There is some disagreement in this thread on the expected lifetime for microinverters but there is something that everyone agrees on. Some microinverters will fail within 25 years warranty window. My opinion is that percentage of failed units is so small that it is almost ignorable, I.e if I have 100 IQ7s in in my system and 1 fails after 15 years I would not even bother to replace it. Contrast it with a failure of a string inverter with common turnaround time for having replacement installed measured in weeks or even months.

[solarix]

I've had a couple Enphase systems where over 50% of the units have had to be replaced and quite a few SolarEdge systems where we replaced all the optimizers. (Of course, this is in Arizona) Fortunately, most of these were on tilt racked arrays where the replacement wasn't so bad. At least on the SolarEdge jobs we were paid for the labor. We had to charge the Enphase customers whose original installer would either not serve the customer or was out of business.
Our string inverters take 5 minutes to swap out, we keep a loaner unit in stock and the manufacturer replaces that and pays us well for the truck roll. String inverters are honest about their 10 year warranties. Microinverter companies are scamming the public with their claims of 25 year reliability.

[SunEagle]

Some failures would always happen, no matter what. Enphase eliminated labor reimbursement for replaced microinverters when the company was in danger of folding. It did make sense since nobody else had the same policy.

There is some disagreement in this thread on the expected lifetime for microinverters but there is something that everyone agrees on. Some microinverters will fail within 25 years warranty window. My opinion is that percentage of failed units is so small that it is almost ignorable, I.e if I have 100 IQ7s in in my system and 1 fails after 15 years I would not even bother to replace it. Contrast it with a failure of a string inverter with common turnaround time for having replacement installed measured in weeks or even months.

I would say there are people that may or may not agree with you and they are the ones that install the equipment.

As for me the cost of installation for the micros is much more then the cost of a quality string inverter. But again to each their own business on what they want to spend or deal with.