Grid-tied solar

[dave1949]

A Mother Earth News article about solar electric. Good overview.

More Affordable Solar Power - Renewable Energy - MOTHER EARTH NEWS

Apparently with an accelerated depreciation program, businesses can get more/better subsidy benefits than individuals.

 

[dave1949]

I have the numbers for August, my first complete calendar month.

460.7 kWh (solar) + 284 kWh (IN from utility) - 330 kWh (OUT to utility) = 414.7 kWh used with a credit of 46 kWh's.

My usage last August (2011) was 305 kWh, it looks like adding the electric water heater accounted for about 110 kWh's this August.

I think I'm off to a good start. I'm sure any accumulating credits will be used up quickly in gloomy December.

 

[not2old]

For example, if a person installs an outdoor wood boiler, or a geothermal system, are the cost of those included in tax evaluations in your areas?[/QUOTE]

Here in British Columbia, we are taxed on the market value of our property. If you could sell your property for more money after the installation, your taxes will be higher.

 

[dave1949]

For example, if a person installs an outdoor wood boiler, or a geothermal system, are the cost of those included in tax evaluations in your areas?

Here in British Columbia, we are taxed on the market value of our property. If you could sell your property for more money after the installation, your taxes will be higher.[/QUOTE]

Thanks. I have been able to get more info on this. It seems the town in question, New Sharon, Maine, is using their legal right to tax personal property and taxing turbines, geothermal and solar systems as personal property. It's all second-hand info, so I am not 100% sure about the details.

The way town budgets work in Maine is they establish a budget based on prior year expenditures. Each year is a new ballgame because the school budgets change, the amount of revenue sharing from the state changes, and the towns share of the county budget can change depending on the county budget.

Once that budget total is fairly well known, the budget is divided by total property tax (real plus maybe personal) valuation. This establishes a tax rate per thousand dollars of valuation. The rate is typically anywhere from $12 to $25 per thousand depending on how high or low they make their property evaluations and how up to date it is. Any tax collected on a personal property basis will decrease the tax needed to be collected on real property because total tax revenue cannot exceed the budget total.

So, it becomes a question of what portion of tax revenue comes from what type of property, a $25,000 geothermal or solar system, a large house or a piece of land. Our local tax clerk is against personal property taxes, they are difficult to appraise and legally difficult to collect if unpaid. Apparently the law differentiates on town remedies. A town can put a lien on real property for unpaid tax, and eventually own it. The law does not allow that for personal property tax in arrears according to her.

I still have some digging to do to fully understand the real versus personal issue.

 

[Redneck in training]

Here is a link to how it is done in Iowa. Iowa Department of Revenue - Iowa Taxes The tricky part is the estimated property value. So technically it might be possible to increase the tax if you install outside wood burning furnace but I doubt they will bother to do so. At least in Iowa I have not heard about such case. In fact I think there is a tax credit for alt energy systems.

 

[dave1949]

The results for the month of September, 2012:

480.9 kWh generated + 268 kWh in from utility - 364 kWh out to utility = 384.9 kWh net use.

The 384.9 kWh is 90 kWh more than September of last year, so I attribute about 90 kWh usage to the new elec. water heater. Last month the variance from last year was 110 kWh, so the water heater must be using around 100 kWh per month, that's for two adults.

The solar system has generated 998.6 kWh since it was installed July 25, 2012.

I currently have a net credit of 142 kWh with the utility. Yesterday and today were rainy and heavy overcast all day long. The system only generated about 1 kWh each day. On the good sunny days, the system is putting out slightly over 25 kWh. That is better than last month when a good day was 22 kWh. The sun angle is improving and the daytime air temp highs have been in the 60's to low 70's for much of this month, which helps panel efficiency.

I am seeing some 3600 and 3700 watt outputs at peak times now (around solar noon). The system is rated at 4300 watts peak output.

So far, so good. I am really surprised the elec. water heater usage is as low as it is. That is making a huge difference in the system's ability to meet our total usage, which is not at all what I had anticipated.

 

[cmore]

Thanks for keeping us informed.

 

[dave1949]

You are welcome, cmore. I will post the monthly performance for those who are curious about grid-tied solar, and want to see actual results from a known location. Heck, I'm curious too :laughing:

September is the 4th best month, and October is in 8th place, according to the PV Watts model, so we shall see.

 

[Redneck in training]

Thanks for the offer to report the performance of the solar. My wife just talked to the bank and we might get approved for a loan to finance our system. Therefore I am also interested about actual versus the predicted production (If you can report both numbers it would be great). I am hoping to build our system sometime in second half of November unless something bombs the effort in the last minute.

 

[dave1949]

Thanks for the offer to report the performance of the solar. My wife just talked to the bank and we might get approved for a loan to finance our system. Therefore I am also interested about actual versus the predicted production (If you can report both numbers it would be great). I am hoping to build our system sometime in second half of November unless something bombs the effort in the last minute.

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.

 

[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.