Grid-tied solar

[sdkubota]

Good point.
The PVWatts model AC kWh predicted/actual:
Aug. 383/460.7
Sep. 394/480.9
Oct. 369/TBD
Nov. 283/TBD
Dec. 331/TBD

I don't know why we are ahead of the model as much as we are at this point. We have had what seems like a lot of nice sunny weather until two days ago. I suppose it averages out over the months and years, so I wouldn't assume it will always beat the predicted value. It will be interesting to see how it shakes out.

Good luck with getting your system.

I have a small 1,080 sf, 1 1/2 stories, super insulated all electric home heated with a heat pump. My average monthly electric usage is: Aug thru Oct = 1500 kw/mnth, Nov = 2800 kw/month, Dec = 4500 kw/month. Your energy production couldn't keep my light bulbs on and at $.06 /kw amounts to $22/month savings. Tell me again what you have invested?

 

[madmax12]

If I remember correctly from earlier in the thread, he believes in the cause, whether he saves money or not. His motivation is different than some, and any savings is a bonus. That's my recollection, anyway. I donate time, money, and things. To some, that wouldn't make sense. If he believes solar is a way to help preserve the planet, then he might see solar as a form of charity.

 

[Redneck in training]

Good point.
The PVWatts model AC kWh predicted/actual:
Aug. 383/460.7
Sep. 394/480.9
Oct. 369/TBD
Nov. 283/TBD
Dec. 331/TBD

I don't know why we are ahead of the model as much as we are at this point. We have had what seems like a lot of nice sunny weather until two days ago. I suppose it averages out over the months and years, so I wouldn't assume it will always beat the predicted value. It will be interesting to see how it shakes out.

Good luck with getting your system.

Thanks for the numbers. I did simulation with three different models. PV Watts, SAM downloaded from ENREL and Iowa Energy Center Solar Calculator at Solar Calculator Tool - Iowa Energy Center The Iowa Energy Center calculator predicted significantly higher output than PV Watts or SAM. The numbers were similar to your production.

 

[Redneck in training]

osts

If I remember correctly from earlier in the thread, he believes in the cause, whether he saves money or not. His motivation is different than some, and any savings is a bonus. That's my recollection, anyway. I donate time, money, and things. To some, that wouldn't make sense. If he believes solar is a way to help preserve the planet, then he might see solar as a form of charity.

People buy Porsche and nobody ask them what they saved by doing that. I am planning 25kW system for about one third of a Porsche costs. It should produce about $300/month (zero my electric bill) and pay for itself in about 9.5 years. If it lasts 20 years it will make additional 36000 not taking into account electric power cost increase or inflation. Just read on Internet that MidAmerican Energy (our power generator) applied for rate increase. My bet is that it will be approved and the rate will jump up about 10%.
Solar is almost there in financial viability. If you can install it by yourself then is viable. If you have hire a contractor then the payback is still too long.

 

[Redneck in training]

I have a small 1,080 sf, 1 1/2 stories, super insulated all electric home heated with a heat pump. My average monthly electric usage is: Aug thru Oct = 1500 kw/mnth, Nov = 2800 kw/month, Dec = 4500 kw/month. Your energy production couldn't keep my light bulbs on and at $.06 /kw amounts to $22/month savings. Tell me again what you have invested?

It is true when your cost of power is $0.06/kWh solar is hard to justify. We pay $0.109/kWh and there is a great chance the rate will go up about 10% in near future.

 

[deezler]

I have a small 1,080 sf, 1 1/2 stories, super insulated all electric home heated with a heat pump. My average monthly electric usage is: Aug thru Oct = 1500 kw/mnth, Nov = 2800 kw/month, Dec = 4500 kw/month. Your energy production couldn't keep my light bulbs on and at $.06 /kw amounts to $22/month savings. Tell me again what you have invested?

Ummm, what? In December your "super insulated" home uses 150 kWH per DAY?!? That is a ludicrous amount of energy consumption. You should be able to heat a tiny super insulated house with 1000 watts of electric heat, right? That would only be 1/5th of the energy use that your home sucks down. I am confused.

 

[dave1949]

I have a small 1,080 sf, 1 1/2 stories, super insulated all electric home heated with a heat pump. My average monthly electric usage is: Aug thru Oct = 1500 kw/mnth, Nov = 2800 kw/month, Dec = 4500 kw/month. Your energy production couldn't keep my light bulbs on and at $.06 /kw amounts to $22/month savings. Tell me again what you have invested?

See Post #3 for the cost details.

My electric rates are 0.15 per kWh. My year-round usage averages about 11 kWh per day. My monthly usage last year, prior to switching to the elec. water heater, ranged from 261 kWh in March to 540 kWh in January--we had a long cloudy period and needed to use our elec. oil-filled radiator space heater in the bedroom. So, my rates are a lot higher than yours and I use a lot less electricity.

My solar system also replaces the propane that was being used by the old water heater, about 260 gal per year at $3 to $3.50 per gal. That's why I have been comparing monthly usage to the same month a year ago, to see about how much the new elec. wtr. htr. is consuming. The system will pay for itself, it takes time.

Your usage does seem like a lot. Is that in the ballpark for your location? If not, I would look into an energy audit, infra-red imaging, check the meter, etc. Using a heat pump and having high consumption, I would guess the auxiliary electric heat elements are on a lot, assuming you have those.

 

[dave1949]

If I remember correctly from earlier in the thread, he believes in the cause, whether he saves money or not. His motivation is different than some, and any savings is a bonus. That's my recollection, anyway. I donate time, money, and things. To some, that wouldn't make sense. If he believes solar is a way to help preserve the planet, then he might see solar as a form of charity.

You came pretty close, thanks. I don't know if I think of it as comparable to charity, I do believe it helps the planet in a very small way that if multiplied by millions of others, would have a huge positive effect. A large part of my thinking is that our actions have consequences that we are responsible for, we all agree to that concept I think. We don't all agree on the consequences of our actions were energy is concerned, and we aren't always able to avoid the consequences. But when I can, I do try.

 

[deezler]

Dave, I also want to add my thanks for your continued updates in this thread.

I'll be building a home in southeast Michigan over the next couple years, and would really like to add in grid-tied PV from the start if I can afford it.

If you can do it in Maine, you can do it anywhere. Bravo!

 

[EE_Bota]

I have a small 1,080 sf, 1 1/2 stories, super insulated all electric home heated with a heat pump. My average monthly electric usage is: Aug thru Oct = 1500 kw/mnth, Nov = 2800 kw/month, Dec = 4500 kw/month. Your energy production couldn't keep my light bulbs on and at $.06 /kw amounts to $22/month savings. Tell me again what you have invested?

We are not apples to apples, so no use sweating comparisons. My house is poorly insulated. The attic is shallow...hard to put loads of insulation up there. I don't think the walls are insulated. I could fix that, and the crawl space could use some work too.

My house was all electric until last year. Even so, worst summer bills were around $50 and my all time worst winter bill was $158*. That bummed me out.
*1831 kwh

Anyway, your post taught me something...I had no idea that folks up in SD could use a heat pump to heat a house. Sometimes I hate to see mine try to do that down here even. I have a really nice one, a Carrier Infinity system, but (now) I have an EPA soapstone stove and cords of oak, hickory, maple, and misc and I try to use that to keep the heat pump from beating its brains out. I could use the exercise in the winter, and I think the flames are soothing. I'm not sure it pays out, but some things are about fun and peace of mind.