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Help, can I do solar without "grid-tie"?

Piney999

Member
Feb 27, 2016
406
191
East of Pikes Peak, Earth
So, I had already ordered Tesla solar and two power walls, but after many delays, I have been told by my electric company that I can not do a Grid-tied system. There is "already too much solar on the line" is what I was told. With that in mind, what are my options? My thought is, do a small Solar array, and perhaps add a power wall, and just have the solar charge the three walls during the day, and run off the walls at night. Does this work and is it possible? Tesla hasn't gotten back to me, but I hope this community can arm me with some good ideas before I talk to Tesla. Thanks in advance!
 

holeydonut

Supporting Member
Jun 27, 2020
1,866
1,253
East Bay NorCal
I think you're going to have a tough time finding a way to get this all approved and integrated into your home in the way you want.

Like if you set up a new solar array that only stores energy meant to power a pool pump or well pump that is not grid-tied at all, I think that would be a cool project and likely something to get approved since it's not touching the PoCo infrastructure.

But if you're looking to create an 'off grid' pile of clean energy that you can push to your house in a pinch, I doubt your installer, or city, or PoCo would allow that.

I am curious how there is "too much solar on the line"... where is that assessment coming from? Like PG&E hasn't even come up with that weird excuse, and I heard every excuse from them to block my solar and ESS lol.
 

gpez

Member
Apr 25, 2019
689
567
USA
So, I had already ordered Tesla solar and two power walls, but after many delays, I have been told by my electric company that I can not do a Grid-tied system. There is "already too much solar on the line" is what I was told. With that in mind, what are my options? My thought is, do a small Solar array, and perhaps add a power wall, and just have the solar charge the three walls during the day, and run off the walls at night. Does this work and is it possible? Tesla hasn't gotten back to me, but I hope this community can arm me with some good ideas before I talk to Tesla. Thanks in advance!

Modern systems can grid tie but not export. Is that a possibility with your utility?
 

nwdiver

Well-Known Member
Feb 17, 2013
8,115
10,584
United States
So, I had already ordered Tesla solar and two power walls, but after many delays, I have been told by my electric company that I can not do a Grid-tied system. There is "already too much solar on the line" is what I was told. With that in mind, what are my options? My thought is, do a small Solar array, and perhaps add a power wall, and just have the solar charge the three walls during the day, and run off the walls at night. Does this work and is it possible? Tesla hasn't gotten back to me, but I hope this community can arm me with some good ideas before I talk to Tesla. Thanks in advance!

Phocos has a new line of inverters that are designed explicitly to not export.

PHOCOS ANY-GRID PSW-H 5KW HYBRID INVERTER CHARGER
 

getakey

Active Member
Jan 28, 2020
1,321
429
95762
So, I had already ordered Tesla solar and two power walls, but after many delays, I have been told by my electric company that I can not do a Grid-tied system. There is "already too much solar on the line" is what I was told. With that in mind, what are my options? My thought is, do a small Solar array, and perhaps add a power wall, and just have the solar charge the three walls during the day, and run off the walls at night. Does this work and is it possible? Tesla hasn't gotten back to me, but I hope this community can arm me with some good ideas before I talk to Tesla. Thanks in advance!

Where are you that they say there is already too much Solar? I thought CA and FL lead the way and far from being saturated.
In CA, we have entire new developments where every house has solar
 

nwdiver

Well-Known Member
Feb 17, 2013
8,115
10,584
United States
They rejected my application for solar, so I guess that is a form of "in writing". I called to vent, but was told "sorry, there is nothing we can do, you are not allowed a Grid-tied system".

Are there a lot of other roof-top systems in your neighborhood? Might be a local transmission issue.
 

wycolo

Active Member
May 16, 2012
3,095
429
WA & WY
> your loads are operating in series with the grid [nwdiver]

SE website search was no help. So what is this 'parallel/series' concept all about? TIA.
--
 

nwdiver

Well-Known Member
Feb 17, 2013
8,115
10,584
United States
> your loads are operating in series with the grid [nwdiver]

SE website search was no help. So what is this 'parallel/series' concept all about? TIA.
--

In parallel operation there's nothing physically stopping an inverter from exporting to the grid. In series operation the inverter would need to 'willfully' export. The phocos inverters have actually been designed to operate in series with a generator and will not allow any current to flow 'backward' toward the grid/generator since this could easily destroy a generator.

In parallel the inverter, grid and loads are connected to a common bus. In series the grid is connected to the inverter and the loads are connected directly to the inverter not the grid or a common bus.

Screen Shot 2020-12-08 at 6.03.59 PM.png
 
  • Informative
Reactions: outdoors

wycolo

Active Member
May 16, 2012
3,095
429
WA & WY
Lets forget the Generator fwiw, thus we can also forget the double-throw switch, so remove both from the diagram. Then all we have is Phocos' statement that 'during a power outage our inverter will not back-feed the grid'. Not exactly the warm/fuzzy confidence I'd be looking for when trying to explain to local poco how absolutely safe my all-in-one inverter is. So I need to dig further for the schematic that clearly shows this. I have a 5kw MPT unit which presumably is similar to the Phobos. I just d/l the Phocos manual & datasheet - much more than what I have so far for my MPT.

Your 'parallel/series' explanation shows a familiarity with this concept but leaves me scratching my head. And the diagram does not include the grid-protective circuitry so I will have to dig further.

I plan to disconnect from the grid but meanwhile need to understand all this. Also I will have NO interconnections possible between the solar system and the existing house/grid system, just to be safe.
--
 

gcsutton

Member
Jun 28, 2020
94
42
Tucson, AZ
Attached is one of the 'saturation maps' where the local power co will deny a grid tie solar in AZ.

As it was explained to me if there is too high a percentage of solar in an area the power co adapt their power delivery if sun or clouds suddenly appear.
 

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nwdiver

Well-Known Member
Feb 17, 2013
8,115
10,584
United States
Lets forget the Generator fwiw, thus we can also forget the double-throw switch, so remove both from the diagram. Then all we have is Phocos' statement that 'during a power outage our inverter will not back-feed the grid'. Not exactly the warm/fuzzy confidence I'd be looking for when trying to explain to local poco how absolutely safe my all-in-one inverter is. So I need to dig further for the schematic that clearly shows this. I have a 5kw MPT unit which presumably is similar to the Phobos. I just d/l the Phocos manual & datasheet - much more than what I have so far for my MPT.

Your 'parallel/series' explanation shows a familiarity with this concept but leaves me scratching my head. And the diagram does not include the grid-protective circuitry so I will have to dig further.

I plan to disconnect from the grid but meanwhile need to understand all this. Also I will have NO interconnections possible between the solar system and the existing house/grid system, just to be safe.
--

The utility would have no more cause to complain if you installed a Phocos than if you installed a UPS. Just instead of getting energy from a finite battery bank you also have the ability to get energy from solar.

That might be a better way to visualize series vs parallel. Powerwalls operate in parallel. A UPS that you would buy at the store operates in series. You plug it into the wall then plug whatever you want to backup into the UPS.
 

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