2 grid tie quotes and different size systems

[4321loco]

After a decade I am back on the forum but this time talking about grid tie systems.

I have gotten 2 quotes in the past 2 weeks using the same information I gathered from SmartMeterTexas. The systems seem to me way off in size to each other, 17.52kw vs 12.78kw . Yearly KWH usage was 24,202 for 2020 and was used as a base line. The last 6 months I have paid $160 average


Quote 1

Solar Solution 17.52kw System
All panels will face south and installed on a huge car port included in price
48 REC Alpha 365 Watt, Enphase Micro, Sense Monitoring
100% Coverage - 24,400 kWh/yr Solar Production
Current Average Energy Bill: $295

Solar Payment at a 20 Year .99% APR: $165
Solar Payment at a 25 Year 1.99% APR: $152


Quote 2 - 12.78KW system
Half the system will point South and half will face East
Includes nest thermostat, attic blanket, led lights, air tight home service and water heater insulation cover
36 LG 355 Enphase MIcros, Sense Monitoring
Year 1 System Production 17,228 kWh

Solar Payment at a 20 Year 1.49% APR: $185
Solar Payment at a 25 Year 2.49% APR: $206

2020 Monthly KWH readings
1387
1381
1916
2060
2568
2549
1472
2811
397
1732
1835
1841
2253
Total 24,202

My main concern is which system is right for me. I currently pay 8 cents per kwh and I will be required to change companies for net metering and their rate starts at 16 per kwh.

[foo1bar]

Yearly KWH usage was 24,202 for 2020
...
Quote 1 ...
Solar Payment at a 20 Year .99% APR: $165
Quote 2 - 12.78KW system ...
Solar Payment at a 20 Year 1.49% APR: $185


My main concern is which system is right for me. I currently pay 8 cents per kwh and I will be required to change companies for net metering and their rate starts at 16 per kwh.

So
24202kwh @ $.08 = $1936.16
Quote 1: 12 * $165 = $1980
Quote 2: 12 * $185 = $2220

So both options do not look great to me.
1> I'd look for another different company
2> Get a quote for installed price - none of this "20 year payment" crap.
I'd probably give the first two a chance to give you a cash price - but their cash price is likely to be high so that they can give you that 1% or 1.5% APR.

If you want a car port anyhow - then maybe quote 1 has that going for it.
For quote 2, the extrasa included are not worth that much.
Nest thermostat is $130-$200.
Water heater insulation is $20-$40.
LED light bulbs are $1-$2 each.
And "attic blanket" is probably some extra R4 insulation bats or something.


After doing a little more figuring, maybe quote 1 isn't too bad...
24.4MWH is their estimate for production.
I'd ask what kind of angle that car port will have on it's roof - a 4/12 pitch? Something shallower? steeper? Do they have any shade degredation on there?
I used Austin as an address in pvwatts and get 26MWH. But it'll vary depending on location, shade, roof pitch, etc.
My guess is the cash price is going to be ~$50k.
So after fed tax credit it's ~$36k.
Which would be a decent price - it's just that not going solar means you stay at $.08/kwh. And that low cost of electricity makes it hard to find a solar solution that makes economic sense.

[4321loco]

Thanks for the reply. I'm currently at 8 cents per kw after all the miscellaneous fees. I do have a 35 month agreement and not sure what my next rate will be at after the remaining 26 months expire. The previous rates got as high as 13 cents which is something I can take into consideration for future calculations. Now, I would also have to change to either of the 2 available net metering companies with rates at a flat 16 cents buy and sell. My system would need to cover all my usage in order to not purchase at a higher rate.

Going by the 2 quotes of almost 18 and 13 kw, which system is closer to what I would need?



The Quote 1 guys told me they would build me a car port frame and attach the panels to provide the shade. We didnt get into much details on pitch but suggested around 2ft of pitch minimum on a 14' wide car port. Also the car port roof would not use metal sheets but rely just on the panels for shading.

The 2nd quote from yesterday told me it was dumb to spend money to save money. I told them I can build an all metal car port to attach the system with full Southern exposure but still wants to do the install on my roof. I also got some BS I disagreed which was, if you dont sign today you will miss out on the discount. I asked how big is the discount and said 8000.


Additional info

Location is Zapata Texas 78076 or the closet city is Laredo Texas 78045.

No shading from homes or trees with the exception of quote 2 having panels on South and East Side which not sure how that will perform

Quote 2 told me they have a production guarantee which I need to go over the details. They mentioned they would pay the diffrence if my system didnt meet my usage agreement.

Anyways this has been some good reading and really appreciate your time.

[bcroe]

I wonder if you need micro inverters, a string system would probably be cheaper?
In the case of panels facing east and west, they cannot peak at the same time, so
strings from both directions may be connected in parallel to a smaller inverter, than
each having peak capacity. That is what is happening here, very effective. I
manage to annually get 29,000 KWH thru 15KW of string inverters. You could do
better if clouds are rare. Bruce Roe

[4321loco]

The 2nd company told me they do Enphase inverters due to having longer warranty than large string inverters, easier to find issues and lowers down time of warranty repairs. We dont get much rain or clouds but a string inverter would be a way to lower the cost a bit I assume.

I have gotten feedback from 4 local persons that have over a year with thier systems and they all seem to be paying more monthly. The 4 homes had diffrent installers and 1 has a string inverter while the others have Enphase units.

I guess for now I will keep doing research and asking around more questions.

Thanks

[foo1bar]

I also got some BS I disagreed which was, if you dont sign today you will miss out on the discount. I asked how big is the discount and said 8000.

HAHAHAHA
The "It's ON SALE!" sales tactic. (When it's only full price about 1 day a month)

Quote 2 told me they have a production guarantee which I need to go over the details. They mentioned they would pay the diffrence if my system didnt meet my usage agreement.

They said 17MWH/yr - and you used 22MWH in 2020.
It's not going to meet your usage.
Even with the energy efficiency upgrades. (which wouldn't be a bad idea for you to do anyhow - just not worth overpaying for them.)

Is quote 2 from Sungevity or Solar Spectrum? (I've had negative dealings with that company, and it sounds so much like them. I don't think I'd deal with company you got quote 2 from.)

[J.P.M.]

The 2nd company told me they do Enphase inverters due to having longer warranty than large string inverters, easier to find issues and lowers down time of warranty repairs. We dont get much rain or clouds but a string inverter would be a way to lower the cost a bit I assume.

I have gotten feedback from 4 local persons that have over a year with thier systems and they all seem to be paying more monthly. The 4 homes had diffrent installers and 1 has a string inverter while the others have Enphase units.

I guess for now I will keep doing research and asking around more questions.

Thanks

Optimizers are good for shading conditions. That's why they're called optimizers - they make marginal conditions a little less marginal - but at a price. The price is that optimizers in such applications are a violation of the KISS principle. Specifically, optimizer systems have lots more parts and complexity.
So more stuff to go wrong and fail.
Applications with little or no shade are closer to optimum and so have no need for optimizers.

Also, given what shows up around here in the way of problems w/SolarEdge stuff would or ought to be enough to make smart folks do a little homework and not be so eager to drink the SolarEdge kool-aid.

[4321loco]

The 2nd quote was from gosunpro and 1st one from Peg Energy which I am still researching both companies. I told my wife about the sale price tactic last night and that actually got her upset as well. He also mentioned not making a second trip if I did not sign and the forms are actually emailed or faxed lol.


I will not sign until every question is answered and believe that's the right thing.

As of today Friday, 2:12 PM......some Ribeye Steaks sound good.

Thanks bud.

[bob-n]

In the end, it's your decision how to go. But for me, I won't do anything with a payback longer than 10 years. Your hurdle may be higher or lower. Or you may want solar regardless of payback. That's OK, too.

From what I can tell, both quotes will not pay for themselves after 10 years, so I wouldn't do either. Even with a loan, I still use the 10 year rule. To pay for themselves, the systems would have to save you enough money after 10 years that you would have enough savings to make the remaining payments.

My reason for 10 years is that I can't predict the future far enough out. Hardware may fail. The manufacturer may go out of business. Connections might get unreliable. The power company terms may (will!) change with time. I may move. A meteorite or storm may damage the array. The longer the term, the higher the risk that one of these things (or something else completely unforseen) will happen.

My advice is do the accounting and see which plan breaks even in shortest time and then determine if that payback time is acceptable to you.

You don't need formal accounting to get a good enough assessment. Precise accounting would also include consideration for interest rates but you could ignore that and still be relatively close. Today's interest rates are relatively low, although expected to rise. That said, the longer out in time you go, the more important interest rates are and the harder they are to predict.

[khanh dam]

you are not actually getting 1.99% or 1.49% or 0.99% interest rates. Solar loan(scam) companies pay 18% or more of the loan value to the lender and then they raise your solar prices 18% or more and then give you those incredibly low interest rates with a higher price. This is called a "dealer fee" in solar sales industry.

Some companies will drop the price $7500 or more if you pay cash. Paying cash is really the only financially smart move IMHO.


Do you want to buy a house for $100,000 cash or do you want 0.99% interest rate and pay a principal of $118,000? Is the choice. YOu can't see that because it's broken down into monthly terms.

And the only way to compare company prices is $$$/watt. get the total price and divide by # of watts.

[4321loco]

[QUOTE=khanh dam;

And the only way to compare company prices is $$$/watt. get the total price and divide by # of watts.

[/QUOTE]

Thanks. The bigger system was actually for economical. There is 2 houses on my street that will go online so I will try talking to owners after there system runs 2 or 3 months. My KW rate is currently low so the ROI is longer than I would want.

[bcroe]

And the only way to compare company prices is $$$/watt.
get the total price and divide by # of watts.

My opinion, what you want to compare are the annual KWH produced, to $$$$
Bruce Roe

[SunEagle]

My opinion, what you want to compare are the annual KWH produced, to $$$$
Bruce Roe

While I agree with that statement it can be done only after you have installed the system. Which may have been an expensive outlay but did not provide what you needed.

[J.P.M.]

While I agree with that statement it can be done only after you have installed the system. Which may have been an expensive outlay but did not provide what you needed.

Well, there's a lot of that type of analysis that's done all the time to estimate a system's cost effectiveness before it's acquired. Happens on this forum all the time.

Both $/installed STC W (or kW) or $/kWh generated per installed STC W (or kW) per time period (such as a year) can be used. To get the second divide $/installed STC W (or kW) of the first by the annual production in kWh/yr. per installed STC kW from a model. The first is a valid way to compare one system's cost to another provided they are of equal STC size, in the same location and the same orientation. But that won't tell much about whether or not any system is capable of producing power at a cost that's more or less than grid power. That's where the second parameter is useful but also limited because the weather varies as do POCO rates. Better than either is LCOE (Levelized Cost Of Energy) type analysis done for all systems and also for grid supplied power (but note the LCOE of grid supplied energy is not the same as the the price of electricity per kWh). The problem with LCOE anaylsis is that, like anything that makes assumptions about the future, it's a probabilistic model and so it produces results based on probabilities and so viewed with suspicion by some. But all those tools can't be used in a comparison of alternative analysis where a PV system's cost effectiveness is compared to doing something else with the money it took to acquire the system, but that's off topic.

As for modeling and it's validity, models such as PVWatts use "Typical Meteorological Year" as the basis for smoothing data over many years and that's usually good enough for production modeling over a L O N G time like 10 or 20 years or more. If that type of analysis is sufficient, and it seems to be good enough as long as we can all live with the idea that there's no way to model system output much more reliably than maybe 5-10 % over any 365 day period, then either $/installed STC W (or kW), or $ cost per kWh produced per installed STC W (or kW) can be used. Bruce's number gets to the root quicker, but $/installed STCW (or kW) is the more common parameter used, even if it is less applicable.