Actually the reason I was asking is my long term plan is to purchase a larger tract of land, about 20 acres, and was thinking of clearing a portion, so any solar panels would not be threatened by falling trees or in the shade. I was just curious if this option would be at all feasible.There isn't any snow in the area I live, but hurricane's do have a habit of hitting us, so the tree thing was important and I am not too thrilled about mounting them on my roof top because of the storms. Currently tracts of land that size in the country aren't too much more expensive than a city lot in a good area.
I'm so jealous. I've been forbidden to shade our grass with PV panels but all it does is sit there and grow... a city building on the lot next to ours has thousands of square feet of roofspace but I can't get away with it...
It's easily feasible but a conservative payback would be 15-20 years, depending on prices, rates, & credits.
There are three ways to look at PV costs. First, there's the "dividend" rate on your electric bill savings. If you spend $30K on a PV system and it reduces your monthly bill by $50 then you're getting a 2% dividend. It's financially better to buy a blue-chip dividend fund, but solar sales guys love to use this math because people love to use it to justify the purchase. They'll also point out that utilities raise their electric rates, so your "dividend rate" will increase over the next 20 years-- but probably not as fast as Phillip Morris or Exxon.
The second way is the payback. A $50/month savings will add up to $30K in 50 years. PV systems are widely quoted on a 25-year lifetime but systems from the 1970s are still pumping out electrons so 50 years is hypothetically achievable. However most investors are unwilling to wait around that long, even though that monthly savings will climb as utility rates climb.
The third, and most conservative, is opportunity cost. If you plunk that $30K in a decent small-cap value fund appreciating 6%/year after taxes then it's going to take a very long time for a $50/month contribution (starting from zero) to compound above it. Even despite rising electric rates.
Despite the investment, PV systems have no value for home buyers. If you try to sell your property you will not recoup the price of the PV installation.
Installation prices are anyone's guess. Research is promising and the media loves to trumpet "The next big solar breakthrough!" but commercially there haven't been any great leaps forward. Most of the price drops have been due to volume production, but Germany & Japan have created so much demand for PV panels that prices have been rising again while production ramps up. In general, though, I believe panels will be cheaper in 3-5 years. Last-generation technology (panels that are 5-10 years old) is already on sale at half-price-- as are cosmetically blemished new panels. Panel racks and inverters are much better as the materials & technology improve, but the big advantage goes to the installer who can take advantage of faster installation times. They'll want to install certain racks or inverters because they have the special tools & training and can do it faster (more profit margin) than some other system you may prefer.
But wait, there's more to add to the spreadsheet. Your $30K investment may get an installation credit from a local utility, a locality & state tax credit, and a federal tax credit. Some of those credits may expire in 2008, so don't wait until October to make a decision or you'll be paying a premium for an installer's time. Just to make things more interesting, our Hawaii credits are only good to the extent of our actual taxes owed (no refunds) so we have to carry them forward 4-5 years to use them up. You may be in a similar situation.
Because most credits are capped at an annual amount or a percentage of the spending, very few owners buy it all at once. Most buy a cheap 1 KW system with an oversized inverter, take the credits that year, expand the system with another 1-2 KW of panels the next year, take more credits, and expand the system to capacity in the third year. That maximizes credits (which tend to accumulate faster than monthly electric-bill savings) but it stretches out the installation.
Then your utility adds their own rules. Hawaii used to credit net-metering agreements monthly. If you made more than you used that month, your usage went to zero and your excess production wasn't carried over. Now that we have a digital meter the net metering is a rolling 12-month account. However it still makes no sense to produce more than we'll use in a year, especially if we drop our consumption via other energy-savings appliances (or by having our kid move out). Most utilities credit net metering at the residential retail rate (your electric bill) but if you're producing "too much" (as determined by them) then you may be reclassified as a power producer and only reimbursed at the wholesale rate. Bad deal.
Finally there's the "hobby" or "green lifestyle" issues. I thoroughly enjoyed the hunt, the design, the installation, the expansion, and the tracking. (The payback is an unexpected bonus.) It's a hobby that keeps on giving, too-- we're buying a Prius in a few months that I hope to convert to a plug-in, which could justify the acquisition of a
second 3KW PV array to recharge its batteries. But I have a lot of math to do on that spreadsheet.
You can go two ways. If you want to do your own installation labor and you understand electrical code/safety, then have an electrical contractor install a small PV array with a huge inverter. You'll want an exterior-grade inverter (or a weather-resistant shed/bunker) and panel racks rated for whatever weather you're going to have to endure. They'll need to understand that you want plenty of room for expansion, which implies an inverter that can handle five or six inputs of up to 600 VDC each. Then over the coming years you can buy more panels (eBay, Craigslist, discount outlets, wherever), build your own racks, connect them electrically, and enjoy the process.
If you want the benefits without having to labor, you could find a local installer who's willing to take on a 3-4 year project while you maximize your tax credits. You'd want someone with volume discounts on panels (and inverters) and who was willing to be flexible on their labor rates if you're flexible on schedule.
If you're not dealing with snow (and especially if the temps stay above freezing) then you may want to consider a solar water-heating system before you go PV. Non-freezing solar-water systems typically have a 5-8 year payback compared to PV.
With a submariner's experience at maintaining grid voltage and dealing with lead-acid storage batteries, I wouldn't recommend going off the grid unless you have to. Maybe someday when NiMH or Li+ batteries are easy to recharge at high rates, but even modern lead-acid batteries are no fun to maintain.