solar panels wired to house current

[saturnsc2]

we have about 700 watts of solar panels mounted on our back porch & at this time all they do is charge some batteries for emergency use, but i heard of some people having them wired to their house current to reduce their electric bills.  i think this would be a better use for them than what we are doing now with them.  i need some info on this as like who can do this, what's needed, cost, ect.  any info is appreciated.  thanks...

[DamonHD]

What you are thinking of is called a "grid-tie" inverter.

That is what I use most of my panels for.

Details of what you need and if you are even allowed to do it will vary greatly depending on where you are.

Rgds

Damon

[jclaudii]

Here is a definition of grid tie

http://en.wikipedia.org/wiki/Grid_tie_inverter

Basically, as I understand it and have researched it, you need a particular inverter.  There are a ton of them out there ranging from a few hundred to a few thousand dollars.  Some of the big names are xantrex and outback.  I ran accross this list http://www.gosolarcalifornia.org/equipment/inverter.php that has a majority of invertner makers of what is approved for the state of California.  

You basically first need to look up or call your local utility company and ask them to give you some info on it.  It varies from state to state and from power company to power company.  

But you basically just need this "grid tie" inverter that allows you to connect your batteries, your solar, and your house feed together in harmony.  This inverter also outputs a pure sine wave so you have the exact same electricity as the electric company.  This is usually why they cost a little more.  

Good luck and let us know how you do.  

[Opera House]

I just don't think you would ever be able to pay off the cost of a grid tie inverter. Find some use that you could this power for as it is.  A pre water heater would probably be the best use, lighting and heating are others. I run a small freezer off my panels.

[imsmooth]

I disagree about not paying off the inverter.  It depends on if you State offers a good rebate.  I got 12.25kw of solar panels and 3 Sunnyboy 3.3kw inverters.  NJ paid for 60% of the system.  On top of this I sell my SRECs to the power companies in addition to having a $0 electric bill.  My breakeven will be in 4yrs from my time of first use.

[Ungrounded Lightning Rod]

How much are they paying for SRECs and how many are you selling?

I figure your system is probably generating about 22 MWHr/yr.  Wikipedia says that on the open market they fluctuate between $9 and $90 with typical being about $20.  At $20/MWHr that would be something like $440, though I'd expect you to be paid somewhat less to cover their bureaucratic costs and maybe only get credit for the part you fed the grid.  Then again if they're hard up for meeting a mandate they might pay a premium.

Did I come in anywhere near right?

[imsmooth]

You are not looking at the right SRECs, or at least for NJ.  I generate about 11-12/year and have sold 8 so far this year.  I got $650/SREC.  I only generate about 12,000kwh because my roof with the panels is slightly south of East.  The SRECs are defined as energy generated, and not what I sell back.  Excess energy to the grid is saved by my electric utility as a credit, and then cashed in at the end of the year at the wholesale price (about 1/2 of what I would have to pay).

[DamonHD]

I'm getting severe panel envy!

I hope to generate somewhat over 2MWh/year!  B^>

Rgds

Damon

[Chuck]

As others have commented, it depends on where you are as to whether there are government sponsored/mandated programs you can get into that make it worth doing.

In Colorado the programs are very size dependent. A small system like yours wouldn't get you much, and may never pay for itself, although it kicks in some up front costs. If you could get rid of the meter charge it would help. A larger system gets you closer. The incentives are made to benefit those who can put a lot of money up front. They are also limited, so once the utilities get to a certain percent RE, it goes away. The big wind farms are taking the lion's share.

I have 1.6kw PV installed and figured out that it wouldn't be worth getting hooked up to the grid, even if it didn't cost me anything (fat chance of that). I might feel differently if I was already paying for a connection however.

[Ungrounded Lightning Rod]

Sweet.  More than half a grand per installed KW per year on top of the state picking up almost 2/3 of the install cost makes a big change in the break-even calculation - even WITHOUT the money from the power itself.

[carlb23]

I live in New Jersey as well and we have 10kw of solar installed and received 70% of the installed cost back from the state in 2004 when we installed the array.  We face due south and the panels are at a 28degree tilt angle.  We produce about 12.6Mwh per year and have sold 6 so far this year for 650/Srec.  I will have another 6 to sell at the end of May plus we save about 2,000 dollars on electricity and will even have some to sell back at the end of this month about 2Mwh(we true up annually with the utility). We have had a 0 dollar electric bill since December 2004 and we even installed a Air source heat pump to heat the house in the winter and cool it in the summer so we only need to pay about 30 dollars a month for natural gas for cooking water heating and cloths drying. Our home is a 2800 Square feet two story colonial with a full basement.