# Cost for a 120 KWH/mo system?



## raymilosh (Jan 12, 2005)

Hi all.
My elec bill says i use about 120 kwh per month or a little less. I run light bulbs, a regular water pump, septic pump, regular refrigerator and a 220 volt welder occasionally. 
I haven't done enough research to know how much it would cost me to install a PV system to handle that load. Assume that I would buy, install and maintain all components myself
It's unlikely that I could afford it... but I'm interested to hear a ballpark figure, nonetheless. 
How much would it cost for a system that produced 50kwh/mo?
How much are upkeep costs for battery and other componant replacements?
ray


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## WanderingOak (Jul 12, 2004)

For starters, many conventional household items are way too thirsty to run on a PV system. Your current well pump, 'fridge and welder will probably not be usable. Since the welder is only occasional, you could get a generator for that. The 'fridge and well pump are a different story. You could either go with a hyper-efficent electric refrigerator designed to run on PV ($$$$$) or a propane powered unit. For the well, you could either convert to a low voltage DC pump, or go with a wind pump and holding tank. The above improvements could be done before you went off the grid.

For pricing, backwoods solar (http://www.backwoodssolar.com/CatalogIndex2/Catalog2.htm ) has good information. They have a free print catalog that you can send away for.


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## Hip_Shot_Hanna (Apr 2, 2005)

If you have a reasonsably new fridge freezer they dont use much more energy than the specail low energy models , 
the 220 well pump is a non strarter , there are very expensive 220 inverters out there , its probably cheaper to buy a solar well pump pannels and batteries complete .


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## SolarGary (Sep 8, 2005)

Hi,
The average US home uses about 1000KWH per month, so you are doing very well.

Some of the PV folks can probably give you better numbers, but here is a rough cut. 120KWH is 4 kwh per day. A 1KW PV rig would generate about that much if you have reasonable sun. The rough rule of thumb is $8 to $10 per watt depending on whether you want a strictly grid tied system or a system with batteries. So, the 1KW PV rig might cost around $8000 to $10,000. You might be able to cut that back some with more conservation, looking from bargains, and doing the installation yourself, but the panels alone are about $5 per watt.

If you live in a climate that requires heating the winter, then installing some solar heating would give much more bang for the buck. This might be direct gain south facing windows, solar heating collectors, an attached sunspace, ... If you are prepared to do the work yourself, you may be able to save just as much energy as the 1KW PV rig generates for a few hundred dollars.
If this is of interest, you might take a look here:
http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm

Or, if your climate is dominated by cooling loads, take a look here:
http://www.builditsolar.com/Projects/Cooling/passive_cooling.htm

Gary


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## WisJim (Jan 14, 2004)

Our 1.5kw array (12 Kyocera 125G panels) produces almost 6 kw-hrs a day, on an annual basis. (actual output for Sept 1, 2004 through Sept 1, 2005 was 2172 kwhrs, or 5.95 per day). The panels, the mounting rack that I built, wiring to the garage, an Outback MX60 charge controller, and other items to add the panels to our existing batteries and inverter cost about $8000 in 2004. The inverter and batteries cost about another $8000 some years ago, but the inverter and batteries that we have might be overkill for most situations, as it is a 1500 amp hour 24 volt fork-lift truck style battery that cost over $4000, and the inverter is a Trace SW4024.

I would say that, if you did all the installation yourself so you had no labor charges, you might be able to do it for $10,000 to $15,000. The typical homeowner would need to pay for design and installation in addition to the hardware costs.

I would suspect that my 1.5kw setup would produce a bit more power in NC than here in WI, but am not sure, so maybe you could get by with a smaller system. A 1kw system should produce almost 4 kw-hr a day average in my location. BUT I have not made allowances for battery, inverter, and other losses in the system.


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## mightybooboo (Feb 10, 2004)

You are the perfect grid tie candidate.I know thats not what you asked,but it is part of the answer.

BooBoo


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## wy_white_wolf (Oct 14, 2004)

mightybooboo said:


> You are the perfect grid tie candidate.I know thats not what you asked,but it is part of the answer.
> 
> BooBoo


Raymilosh may be a good canident for a grid-tie system. Too bad North Carolina's net metering law heavily favors the Power company.

http://www.dsireusa.org/library/inc...Code=NC05R&state=NC&CurrentPageID=1&RE=1&EE=0



> Treatment of Net Excess: Credited to a customer's next monthly bill, but reset to zero at the beginning of each summer (June 1) and winter (October 1) billing season. Any renewable-energy credits associated with net excess are granted to the utility when the balance is zeroed out.


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## mightybooboo (Feb 10, 2004)

Right WWW,Ray may need to produce less than needed on his system,then 'use' the power company for his big loads and a bit excess needed,and in the foul weather times use bought power too.

Throw in some batts for backup when they are down.
Also would allow expansion as use and dollars dictate.

I know this would be a very expensive system he envisions to be totally free at his current usage.

Just a thought guys.

BooBoo


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## Jim-mi (May 15, 2002)

Thanks for posting that Wwolf.
Thats just about how it reads here in Michigan. 
They sell for 0.083 cents----very soon to go up.
They pay 0.295 cents for an IP's generated power.

When oh when will these utilitys wake up and get with it.

Sorry I forgot the allmighty $$$$$$$$$$$ rules.

Theres an awfull lot of folks that need to rethink *their* electrical usage.

Hows that go---Every watt not used is a watt you don't need ($$$) to generate.
something like that.


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## wy_white_wolf (Oct 14, 2004)

Jim-mi

I think Michigans is much better:



> Treatment of Net Excess: Credited to customer's next bill; granted to utility at end of 12-month billing cycle


At least they only take any excess away once a year and maybe you can negociate the end of billing cycle to be at the end of the low production period (early spring most areas). The real killer of NC is the set dates. Aug. and Sept. are most areas high production time (long days, few clouds) so you just start to get a bank built up and they take it away from you.


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## raymilosh (Jan 12, 2005)

thanks for all the replies, folks. 
Solar Gary: I have a good passive solar heating and cooling setup and have insulated well and built good curtains. I also built a solar water heater. Wood is used in winter to supplement the space heating and water heating and it also cooks the food...all that is prolly why my bills are so low. I have read your site extensively while I was figuring how to retrofit this house for solar features...so thank you.
Boo Boo: I forgot about the battery-less option. Thaks for reminding me. I have heard that selling excess power back is a losing proposition, but I wonder if it would be worth it if I could avoid the costs associated with batteries. (It costs me about $12 a month to be hooked to the grid and I spend about $4 to $8 a month for the electricity.) 

But WOW, the costs are up there, aren't they. I have really been cutting back on refrigeration and my neighbors and I are working toward a non electric water supply system. Makes me think this electricity stuff is more trouble than it's worth.
I spoze I'll just keep my eyes peeled for cheap PV componants and also keep working toward less and less electrical needs. I have serious doubts that cheap energy sources will last for as long as I would like to last.
ray


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## Jim-mi (May 15, 2002)

----Good For You----

For cutting way back on your electrical usage.

Now to get a few million others to do the same.

Look at another angle of your low usage. When and if the grid does go down you will Not be hurting nearly as much as the yahoo's down the road who use electrical energy like theres no tommorrow.......
Oh what will they do when their electric pickle fork doesn't work because the grid is down. ??

Sorry to say but there's not really any "cheap" (good) equipment out there..
Beware of the too good to be true prices on { cheap} --(junk) equipment.


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## SolarGary (Sep 8, 2005)

raymilosh said:


> thanks for all the replies, folks.
> Solar Gary: I have a good passive solar heating and cooling setup and have insulated well and built good curtains. I also built a solar water heater. Wood is used in winter to supplement the space heating and water heating and it also cooks the food...all that is prolly why my bills are so low.
> ray


Outstanding!


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## Andy Nonymous (Aug 20, 2005)

... my grid usages is currently averaging 2.3kw/day, down from 2.4kw/day last year, yet costing an additional 4 cents a day this year due to an increase in the utility 'base rate'. and that's running a somewhat less than wonderfully efficient chest freezer, a washing machine, compact florescents, a laptop, and a battery charger to keep the Sunfrost going. I really need to get the neighbors to let me drop the tree in their yard that would give me a few more hours of watts to the solar panels I'd like to put on the roof...


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## Jim-mi (May 15, 2002)

Good luck on droping that tree.........lol

Andy jump over to the refridge thread and put your thoughts in about your Sunfrost.

Oh ya, that utility "base rate" ------
Rate increase after rate increase........it Will Not Stop.........


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## hickbynature (Aug 3, 2005)

I visited the steam engine shin-dig in CT recently, and saw the size of some of those fly-wheels. What if one were to build a flywheel, heavy enough to actually run for a while on its own, powering a windmill generator or two? As a cylist, I would consider pedaling for 30 minutes a day to run the thing for an hour. . . .not a a sole source for electric, but as yet another source. 
Stuck in a nasty urban apartment for now, but will attempt this sometime.


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