off to on grid

Posted by Allen B on February 06, 2009, 11:01:06 AM

My 2 cents worth,
I got into this with the motive of getting off the grid.
At first investigation I was told to call the power company and ask about net metering. My power company ask me to explain what net metering was, I did explain. They said very snubbally No. Like I was stupid for even asking, I told them to get ready cause it is coming. Then I was advise to check codes for my solar water heater. Code department told me that they have never been asked that question, and did not know. Poof I was done with them.
I now have solar water heater, 430 watts pv, and a 800 watt windmill. All bought out of state. Drove to pick up panels and collector. Got 1500 watt pure-sine inverter, 2 charge controllers, 1 Windmill by shopping around on-line. I would not reccomend doing it this way. Codes and all. But I like a challenge and adventure. I am shooting for maybe 10 years to be totally off grid and its not looking good. But who knows, Gotta have hope. And just maybe. Alt-e store has been very Helpful and one of the best suppliers I have dealt with. Good luck As we trudge the road to happy destiny.

Posted by Thomas Allen Schmidt on February 06, 2009, 08:20:54 PM

Re: off to on grid (Reply #6)

A grape is to a raisin what a ______ is to a prune?

Below is a few places that can give you more information to juggle around.
Basically though, the cost of a PV system to power a conventional house as if it were "off grid" would cost as much as a life time of electric bills. Its a general rule of thumb that "off grid" is best left to those that want to build a remote home but to have grid power means spending $10k to $20k or more for miles of wire and poles.

Think about it this way. Take your electric bills for one year and add them all up. Multiply that by how long you expect live and pay for your electricity. Thats about how much money you might need to go off grid at your current home that is on grid. Unless of course your already 90 something. Part of the reason for this is battery bank replacements.

Another way to look at it. A 10kw PV array might cost as much as $50k if you can get dealer prices and, after any state incentives and, if you do the work your self. If your in an area that does not "net meter" Then you might be getting "payed" the averted cost for your electricity. What it cost the power company to make it or a city to buy it. Lets say your only getting payed $0.024 cents per kWh. A 10kw PV system might make a 40 kWh a day averaged out over a year. Thats $0.96 cents a day or $350.00 dollars a year. That means this system will have payed for itself in the year 2152 if it was installed today.

After all is said and done. What do you want to do Mr. Butterfield?
It all depends on that and uhh, how deep your pocketbook is. Know what I mean?
In the meantime read up. Knowledge is power!

http://www.dsireusa.org/index.cfm?EE=0&RE=1
http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/
http://www.homepower.com/home/
http://www.solarelectricpower.org/
http://www.cleanerandgreener.org/resources/pollutioncalculator.htm
http://photovoltaics.sandia.gov/
http://www.wholesalesolar.com/bulk-solar-panels-by-the-pallet.html
http://www.aeesolar.com/
http://www.corrosion-doctors.org/Biographies/OhmBio.htm
This is just the tip of an iceburg.

Posted by Steven Sonntag on February 08, 2009, 02:39:06 AM

Re: off to on grid (Reply #7)

Actually not a great idea. Grid tie panels are different. You really need to make the decision right up front. For example if you want to run 12v DC stuff like lights and fans and small appliances, and have some inverters for AC stuff, you'll be buying panels that put out 17-18v to charge 12v batteries. On the other hand, if you want to do grid tie you'll be buying panels that put out 23v or so.

I found this out when I got all excited about 200watt panels I wanted for my 12v system. If the watts are that high, they are probably for grid-tie systems. The biggest I could find (and I'd love to hear from an Alt-E person if this has changed) is 125-130watts for a 12v system.

I've wrestled with this same question and have concluded that if you want to do grid tie, just plan on taking out a big loan and do it all at once. Make sure you do your math carefully on how long your payback will be in relation to utility savings.

If you want to grow a small system into a bigger one like I do, you can do it a few bucks at a time. I'm attacking my ranch in modules and don't feel a need to even have the whole place on one single unified system. I will stay on the grid, but I don't want my system grid-tied cuz our grid power goes down 3-4x a year.

You can buy more panels as you can afford them, but if you're growing a battery bank try to complete it in a few months so you don't end up with batteries of different ages. Also, a huge charge controller like a Xantrex c-60 is not that much more than smaller 30 amp controller, so start with the biggest charge controller you can imagine ever needing.

As your system grows beyond that, you can have entirely different charge controllers and battery banks to do different duties in the home.

That's my perspective on the piece-meal plan. If you want a unified solar system that runs everything, get a loan and hire someone smart.

SS

Posted by Ken Hall on February 08, 2009, 11:00:19 AM

Re: off to on grid (Reply #8)

Steven

You need to learn about MPPT controllers.
http://howto.altenergystore.com/Library-Articles/Solar-Electric-Power-or-PV-Systems/Solar-Charge-Controllers/How-MPPT-Charge-Controllers-Work/a13/
http://howto.altenergystore.com/Sizing-MPPT-Charge-Controllers/a61/
That is how you can make use of the larger/higher voltage panels on a 12vdc system.

Ken

Posted by Tony Butterfield on February 09, 2009, 01:01:12 AM

off to on grid with Enphase Micro-Inverter (Reply #9)

Well,
I am glad I was able to spark a little conversation.

My original goal and my long term goal has changed since I have joined the ranks of solar power users.
Because I am in an old apartment in Houston I have huge electric bills. The apt. complex has no interest in putting in an efficient a/c unit. I spend $315 for 2kw/h per month for a 1000 sq. feet. Doller per sq. foot I am getting really ripped off. At first I just wanted to drive my own window a/c unit with a solar panel hidden on my back porch since a window unit couldn't be any worse then the a/c unit that I have from the apt complex.

But since then I have started to look at buying my first home. It will need to be a run down foreclosure needing help.

My thoughts based on what everyone here has said are now to skip the batteries at the apartment and go to a small grid tie system and some how bundle it into a renovation of the foreclosure. This might be possible with the Enphase Micro-Inverter which I am told can be used to start a "small" grid system and grow with more panels over time.

I think a good goal would be 1.5 kw/h per month for a 1500 square foot home with 50/50 grid and tie in electric.

Maybe the question should be put out to the community is not how many panels or on/off grid system but how many kw is need per square foot of living space.

More thoughts please.

Tony

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