I have heard it is possible to install solar cells on your house and make enough electricity to sell some off to the locar power company. Yet, my EE friends tell me electricity from solar power can only be used to trickle-charge batteries. Since the latter is a slow process, I cannot see one selling much back to the power grid.
Since the two bits of info conflict, what’s the SD on this? - Jinx 
Your friends are 100% dead wrong. I have a 6700 Kw system on my roof. In simplest terms, during the day I sell power to the power company and at night I buy it back. I am part of the overall electrical grid and I have no batteries in my system at all.
If my system was larger I would actually be a net seller like one of my co-workers. Instead my lowest bill for the month has been $19.
Your EE friends do scare me a bit if they somehow think ‘electricity from solar power can only be used to trickle-charge batteries’.
Perhaps they should read more or enter a new field of study. 
Jim
Sure, you can do this, it’s just very expensive.
Solar panels are around $5/Watt (or more) installed. This means that it’s going to cost you $10,000 - $30,000 to offset the average home’s electricity consumption. And, this only works during the daylight hours. To make your home 100% energy self-sufficient requires batteries, which increase the cost substantially.
Also, most utilities buy back energy for much less than thy sell it to you for, which makes ht equation even worse.
Cite on that last part please. In my experience you are wrong on pricing and the last statement. The pricing is higher than you estimated without state help and the electric is at net use. so the price is the same in both directions.
My system only cost $15,000 or so but the state paid 70% of it and the real cost was closer to $50,000 for 6700 watts. The price has only dropped a little in the last few years.
Additionally, another part of the payback is a solar green coupons that you can sell. I have averaged about $500 per year for thee years from these.
Jim
There was probably a misunderstanding somewhere between the engineers and the OP. At a guess, I would say they were probably referring to some specific setup (probably with a very small panel area) when they said you could only trickle-charge, but that the OP misinterpreted and thought they were talking about all solar power in general.
6.7 megawatts? You have a big roof!
This is called “Net metering.” From here 34 states currently have net metering policies (which is much better than a few years ago), the rest don’t. Without net metering, utilities typically only pay 1/3 the cost of electricity they sell.
K is for Kilo in my usage and typical US usage.
Where are you from that K means Mega?
beowulff, thank you for the cite.
From your cite:
It looks like Florida is the last hold out of the large population states. This must already represent over 80% of Americans from a quick mental calculation.
Yeah…
But, y’see, 6700 kW is 6.7 megawatts.
:smack:
Can you provide your average use and also the cost per kw?
Heh, reminds me a bit in Singin’ in the Rain where Gene Kelly is explaining Hollywood magic to Debbie Reynolds, including turning on a series of large spotlights to generate “six hundred thousand kilowatts of sunlight” or some such thing. The movie was set in 1927. Was there that much power generation capacity in the world at the time?
Your EE friends might be joking. It’s hard to say, because jokes customarily involve humor, so without being funny they can’t be easily recognized. Or you might need brighter friends.
That being said, solar cells are very nice for trickle charging batteries. They produce DC without any other electronics involved (I’m counting the cell itself as an electronic device). They produce fairly expensive power, on a capital outlay per watt basis, but can slowly charge batteries that are big enough to supply lots of power for shorter periods of time. And solar cells typically produce their power for most of the day but with unpredictable lapses due to clouds, shadows, and the like. Batteries deliver power whenever you want, if they have stored some. So solar cells and batteries are pretty perfectly complimentary to one another.
But peanut butter and jelly go well together, too. That doesn’t mean you can’t use them with other things.
Tennessee is not a “big” population state, but it is larger than 23 other states on the list. I can’t believe we are dragging our feet on this. Al Gore had to fight local government to get this roof in Nashville.
My EE friends may have been speaking of a self-sufficient system. The first reply to my question says he buys power at night. My EEs were thinking of how solar is used to trickle-charge batteries. This is probably the big disconnect between the two schools of though on solar applications.
My latest Bill was from May 10 to Jun 11 for 33 days. The total was $46.12. The prior bill BTW was $7.96.
We used 867, generated 593 and so were billed 274 Kw in the listed time period.
The KWH charge varies by usage and is broken into Generation and delivery charges. It is tough to give a specific cost other than the average.
How ever you will see an average cost of $0.16832 per KWH.
My average use is still dropping but my average daily use is roughly 26 KWH.
I have a family of four and I chase around shutting off lights not in use.
I have greatly reduced our energy needs via fluorescent lighting. A security light for the driveway that is motion activated and timed for only 10 minutes. I have programmable thermostats and many ceiling fans installed. I am always looking for efficiency on new purchases.
We have an electric oven, electric dryer, central air and an electric hot water heater that cause a lot of our usage. I am looking into a geo-thermal system to reduce the central air and HW heater cost and eliminate my heating oil cost.
When we purchased our primary use TVs we settled on very efficient 37" LCD panels. The other major draw in the house would be the PCs.
Jinx, the trickle charge for a house system does not really exist except very rarely. Even houses that are off grid usually both charge batteries and use the electric converted directly to AC during the day and then draw down the batteries at night. They need to be far more efficient than I am as the batteries are very expensive and take up much room.
Jim
How do you sell power back to the electric company? Do you have to register to do that or does it happen automatically when you hook up some type of generator? If I have a diesel generator in my basement and I plug it into the electrical outlet, will I get a check from my electric company? If I didn’t live in Florida, I mean.
You need to sign up for a metering program. The utility will inspect your system for safety, and if it passes, will install a special bi-directional meter.
BTW, I’m a big fan of Solar PV, but selling electricity back to the utility is a sucker’s game. You are much better off sizing your system to handle your average load, and let the utility handle the peaks - the power you are producing is much, much more expensive than what the utility will pay your for it.
Well, *someone * had to pay for it. Sounds like the taxpayers did. :dubious: Hence your calculations should be based on $50K, not $15K. Plus maintenance and upkeep.
It’s doubtful I’ll ever install PV arrays. Grid power is just too damn cheap to justify it.
Agreed. Solar PV, while promising, is little more than a feel-good alternative at the moment.