theo wrote: I know that they still hit you up for transmission charges
Actually, they don't. Any extra KWH's go out to the grid and they give me 100% credit. I do not pay the power cost OR the delivery charge on any KWH's traded. As long as I bank enough credits the ONLY cost to me is the $6.82 a month. I have no batteries. All extra power goes out to the grid. If the grid goes down, I go down with it. The power compnay will never write me a check. It is technically possible for me to lose credits. Credits are lost if they become 13 months old. Near impossible to lose credits though. I know how many I have "in the bank". If I see I am going to lose credits I turn on an electric heater & burn them off (saving coal). As I said, check with your utility. Some places are different. Some places you sell all power at wholesale & buy it back at retail, but I think other places you sell it at a premium because "it's green", then buy it back at retail. If there is extra, they send you a check!
The think with batteries... not only are they expensive and need to be kept charged, they can ,and do, cause you to lose power. Think about this scenario: Let's say I have a battery system. Today the sun shines. When the sun goes down, the batteries are fully charged. Tonight I watch some TV, surf the Internet, and my boiler runs pumps and fans. In the morning my batteries are 45% discharged. The sun comes up. It is a bright sunny day. By 11AM my batteries are fully charged. Now....what happens to ALL the power that is made the rest of the day? The answer is: It is used as it is produced, or it is lost. So, you have the wife do the laundry, you pump water to fill a tank, you water the lawn, you have the teenagers take a shower & let them use a hair dryer. Still sunny? The power is lost. Buy more batteries? No & this is why: Reverse the scenario.... go three days with no sun. The batteries run down. You WILL start a generator and charge them. It ruins batteries to sit uncharged. If you have too many batteries you will be wasting fuel for the generator. So, at least in my opinion, and I think I present a good case, if you are on the grid it makes sense to be grid tied even though you go down when the grid goes down. It just doesn't matter. If you want power all the time you will
own a generator, but, with a grid tie system the generator gets used a lot less.
Do it again? Yes! I guess one comment.I don't think you put this sort of thing on a credit card. Everyone wants to know how we had all the money. You gotta do what my wife & I did, and that's rarely go to the movies and rarely eat at restaurants. Then after years of driving clunker cars, you get lucky with a 91 Ford Taurus. After four years when you make the last payment, you keep making the same payment & putting it in a separate bank account. The luck comes in when the Taurus actually lasts five more years and you can now pay cash for a new car. Now, keep making those payments & now that you have a four year old car that will surely last another 5 years, you pay cash for solar panels. The solar array is warrantied for 25 years, and should last 40. Time will tell!
Gad zooks.... I'm rambling!