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#195382 - 07/29/10 09:10 PM Grid Interlocking?  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,211
SI,New Zealand
Sorry about the thread title, but being from an area where this sort of technology is pretty much foreign and new, when a given installation generates too much electricity for it's own use, how then does it change over to feed back into the Grid?
How is synchronisation taken care of?

Let's face it, these days if you're not young, you're old - Red Green grin

Tools for Electricians:

#195392 - 07/29/10 11:26 PM Re: Grid Interlocking? [Re: Trumpy]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,076
The inverter syncs to the grid power before it will put out anything (grid down, your solar array is down). It generates power into the grid all the time by trying to make the voltage slightly higher, what you use you keep, what you don't goes to the neighbor.

... or so I understand.

Greg Fretwell

#195399 - 07/30/10 12:02 AM Re: Grid Interlocking? [Re: gfretwell]  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,824
Brick, NJ USA
Greg did a very good synopsis. I'll add that the installers are now 'adding' a KWHr meter to record the solar output. It's a 'regular' mechanical KWHr meter.

One recent comm solar install on a refrig & climate controlled whse reduced the net POCO bill by 40%. I don't have dollar figures & I have to check my notes on the KW/MW solar install, I recall 1MW on each of two bldgs.


#195401 - 07/30/10 06:36 AM Re: Grid Interlocking? [Re: HotLine1]  
Alan Belson  Offline
Joined: Mar 2005
Posts: 1,803
Mayenne N. France
What are they paying for solar generation in the USA? E. d. F. is coughing up 77 cents US at the moment for solar [and charging consumers 18 cents US]. There are thus no 'savings', the question is who's picking up the tab for the 59 cents difference? No prizes, it's the usual suckers getting it in the shorts - in other words, us!

Last edited by Alan Belson; 07/30/10 06:37 AM.

Wood work but can't!

#195403 - 07/30/10 02:05 PM Re: Grid Interlocking? [Re: Alan Belson]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,076
That sounds about right. They are trying to use the carbon tax here to hide some of the cost of solar along with simply using rebates and tacking the cost onto our debt.
The US doesn't really pay our bills we borrow 40 cents on the dollar.
I have been looking and about $4 a watt seems to be about the cheapest you can get the parts, labor extra. When they were rebating this, it made sense but the Florida rebate fund is dry. I am not sure what will come out of the next federal tax law. The current one is due to expire at the end of the year.

Greg Fretwell

#195410 - 07/31/10 02:49 AM Re: Grid Interlocking? [Re: gfretwell]  
Alan Belson  Offline
Joined: Mar 2005
Posts: 1,803
Mayenne N. France
Greg, I got the prices from an EDF offer to fit 250 sq foot of crystaline pv to my roof at over $150 a square foot, "competitive with a new roofing cover in traditional materials". My mate Tony is a roofer and says he would do my entire roof of 4000 sq feet for $30,000 including new rafters, battens and top spec slate, so that's a load of old baloney for a start! mad They reckon it would generate just over $2000 pa @ $0.77 per kwh = 2600kwh/a. The offer is that the French Gummint will lend me the $39,000 install cost interest free. Just 4 stumbling blocks;
1. My roof was rebuilt less than 10 years ago.
2. Small print. The rate paid reduces annually by 10% , till it hits standard tariff.
3. By the time I get my money back I'll be 125 years old.
4. Her indoors says the repayments come outa my beer money.

"I take it that's a no then?"

Wood work but can't!

#195412 - 07/31/10 04:26 AM Re: Grid Interlocking? [Re: Alan Belson]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,076
Our typical roof is shingles and you can get that for more like $3-$4 a sq/ft.

Greg Fretwell

#195429 - 08/02/10 08:53 PM Re: Grid Interlocking? [Re: Alan Belson]  
IanR  Offline
Joined: Dec 2004
Posts: 328
Palm Bay FL USA
Number 4 would be the deal killer for me. beer cry

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