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btattoo
05-07-11, 01:59 PM
I searched the forums here for solar panel discussions and learned quite a bit, but I wonder if the info is outdated. I'm trying to figure out whether to put solar on my roof and need to learn about the technology and economics.

I don't have high energy usage (efficient and relatively small house): 350kWh/month. We have gas stove, heat, water heater, and dryer. I'm looking into a system that apparently has a by-the-panel dc to ac converter (as opposed to just one big one next to the meter), which supposedly increases efficiency.

Figuring in the federal tax credit, it looks like with 7% yearly rate hikes (conservative, especially with smart meters) I could recoup 15k installation after 11 years (ignoring potential house value increase) which seems like too long. At present, I think I'll put it off, but maybe I'm missing something. I kind of want to do it because the 15k isn't earning much and I don't want to buy more gold.

If anyone can share thoughts or solar education resources, I'd appreciate it. -Tim

Kadriana
05-07-11, 04:54 PM
My husband goes to windsun.com for any questions he has on our panels. He also says a 2.5 kw solar panel array should cover your rough yearly power usage depending on the area you live in.

we_are_toast
05-08-11, 10:12 AM
If you're looking at it purely for an investment, there are plenty of other investments that will give you a far better return over the next few years. But you own a car and furniture and a house, and none of them are going to be a better investment than solar panels. So you might want to look at it as part of your life style over the intermediate term, and a good investment over the long term.

Panel prices are dropping fast. The panels I bought 6 years ago are now half the price, and there are other panels that are even cheaper.

The efficiency gains over having the inverter near the panels will be very minimal unless your panels are going to be located very far from the house. The type of inverter will make a far greater difference. Good inverters can be as much as 10% more efficient than the cheap ones, and a good solar controller is also a big +.

Here's a good book about the fundamentals of the subject: The Solar Electric house.

Here's some good online retailers:
Wholesalesolar.com
altestore.com

As Kadriana said, where you live is absolutely critical. You need to know how much sun you get and at what times of the year. Nrel.gov (National Renewable Energy Lab) is a good source with some good info.

If you're not going to do the work yourself, you might want to get a few bids, then check and see if you can contract with a carpenter and electrician, and then order the equipment online to have it done cheaper than having someone who specializes in solar installation. Prices will vary greatly between installers. Be sure you know what you are buying before you buy it.

Your usage of 350KWH is very low compared to the average American which is about 900 KWH/month. Before you buy a solar system, the place to start is to reduce your usage as much as possible. We're very energy conscious and we use 150 KWH/month. I live in the west where it's fairly sunny, and I have a 1.1 KW system. If you enjoy technology and the craft of building, you might find it very enjoyable to play around with various design combinations and see what you can come up with.

c1ue
05-08-11, 10:54 AM
Figuring in the federal tax credit, it looks like with 7% yearly rate hikes (conservative, especially with smart meters) I could recoup 15k installation after 11 years (ignoring potential house value increase) which seems like too long.

Did you also figure at least a 3% return on invested cash? This significantly affects projections on rate hikes and payback time. It was wise to ignore feedin tariffs.

As for installation - the points and web sites noted above are all good resources.

The primary note I would make is that you look closely at the technology in whatever choices you narrow down.

1) Thin film panels are much cheaper, but output losses over time will be much higher. Given that ratings are generally for 20 years, the combination of output losses over time plus investment payback is very key.

2) Efficiency gains. Efficiency gains continue to improve. A doubling from existing levels is quite conceivable in the next 3-5 years.

3) Subsidy availability. There is significant debate on how much longer subsidies will be available. Essentially it is a dogfight between the solar industry lobby pushing for, and budget considerations pushing against. Clearly longer term budget considerations will win.

4) Security and protection. I'd budget for at least a little extra infrastructure to protect your investment, unless you're the type that literally never leaves home.

There are few capital items worth quite so much as solar panels.

While in SD you won't have to worry about hail, equally you wouldn't want parts of your investment damaged by baseballs or rocks, or a 'work' crew visiting while you're away.

btattoo
05-08-11, 05:15 PM
All this is very helpful toast, Kadriana, and c1ue; thanks very much.

I need to do some figurin' using the government solar data and try again to squeeze more info out of my neighbor, who is strangely unwilling to share info about his system (I'm in a row of townhouses that are technically freestanding, with 2" gaps, and he's about four down from me).


Did you also figure at least a 3% return on invested cash? This significantly affects projections on rate hikes and payback time. It was wise to ignore feedin tariffs.

Nope, didn't. Will now.




4) Security and protection. I'd budget for at least a little extra infrastructure to protect your investment, unless you're the type that literally never leaves home.


I was figuring the height (3 story building) would insure me, but perhaps I'll rethink.