# Sharing PV power with another building



## earshavewalls (Apr 26, 2011)

This is a very strange request, one I have never heard before.........thought I'd post it here.

The email was like this:

I have a customer who is considering buying a building that has a 2.5Kw solar array on the roof, this building happens to be next door to his existing business that is appx. 50,000 sq. feet, it is a manufacturing facility and is a pig it eats a lot of electricity. He wants to know if it is possible to pull a permit to pull power from the inverter in the building he is considering buying and feeding his existing business, this would entail trenching the parking lot and installling a couple conduits and feeder wires to feed the main switchgear.  I am also going to call Edison and see if they approve, let me know your thoughts on this.

This question came from a respectable electrical contractor. First, a 2.5Kw PV system is smaller than most residential installations......don't see how this is going to help much with a manufacturing facility. Secondly, this is really close to feeding one building through another, isn't it? (rather than from another). The existing building already has a complete service.

So, where can I find code reasons to not permit this installation? OR Is this somehow permissable? I don't think so, but I will probably spend the next couple of days pouring through the Code to find reasons to deny or permit this suggested installation.

Wayne


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## mark handler (Apr 26, 2011)

It is legal to sell excess photovoltaic energy to the grid. I see no reason not be able to sell it to your neighbor. It might violate State Law but not NEC (CEC). Contact the PUC.

http://www.cpuc.ca.gov/puc/contactus/


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## FyrBldgGuy (Apr 27, 2011)

Look up Micro Grid.


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## earshavewalls (Apr 27, 2011)

I need to modify the OP. The customer got back to me to let me know that the PV system in question is not a 2.5Kw system, it is a 250Kw installation!

I am not sure that a Micro grid is what this is. My take on micro grids is that they are what is being created by all of the home and commercial PV systems being installed currently. These are the same as one large generating plant, when you put them together. This "micro grid" is a power grid created by homeowners and business owners, NOT the utilities. The POCOs don't like them because they don't get to charge us for the construction costs (directly) of private PV systems, but they DO get to charge us for all "improvements" to the grid and for new generating stations.

I don't think a micro grid is something a person creates between two different buildings.

But.......our conversations here in B&S are leaning toward considering this installation.....but only if the two buildings were on a single property under single ownership, with a recorded agreement. We are just waiting on Industrial centers to start asking about PV farms to help feed ALL buildings on the property. I have a feeling this sort of thing is going to start popping up more and more with the advent of more alternate systems, compounded by rising energy costs.

Now, the CMPs need to start considering these types of installations and we really should have some code guidelines specific to this sort of situation......looks like it's time to start submitting proposals for the........2015 cycle????

I'm still sort of on the fence on these, but I now think they may be possible.


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## mark handler (Apr 27, 2011)

A microgrid is a localized electricity generation and loads, This is what you have.

The question is, Is the state going to tax it?


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## earshavewalls (Apr 27, 2011)

I don't see how the state COULD tax it if the two buildings are on the same property, owned by the same individual/corporation. We see buildings supplied through service gear from one building all the time, especially in industrial applications. The only real hiccup would be the POCO (Edison). This guy doesn't want to sell power to another building, just wants to use some of the generated power from the other building's PV system to help defer power costs at the other building without building another PV array.

I am leaning more and more toward allowing this, under certain conditions: single ownership and management of both buildings; both buildings on same lot/property (and recorded as such); GEC from each building interconnected.

The only other thing is how they will split off from the inverter to the other building......it should be interesting to see how they propose to interconnect the systems.

I'll keep y'all posted!


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## Alias (Apr 27, 2011)

Contact the local planning and zoning board and let them know of the proposed linkage.  My take is the company will probably need to get an okay from them.  Then, with planning and zoning, you will get into possible utility easements, lot merges, lot line adjustments, etc.


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## GHRoberts (Apr 27, 2011)

In theory there is no problem, but ...

PV owners are allowed to sell back to the utility. It is not clear that they can provide electricity to other users. I think the second building is an "other user" becasue it has its own service.

I think the utility, the owners, and the permiters should meet and discuss the matter. Other parties might have a reason to offer comments.


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## mark handler (Apr 27, 2011)

earshavewalls said:
			
		

> on the same property





			
				earshavewalls said:
			
		

> next door to his existing business


next door(500 ft) *or* on the same property?

Different Property or Different Owner, there are issues, Same Property and/or Same Owner, No issues


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## FredK (Apr 27, 2011)

mark handler said:
			
		

> .........Different Property or Different Owner, there are issues, Same Property and/or Same Owner, No issues


I agree with Mark's last statement. Same property--no issues.


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## mark handler (Apr 27, 2011)

earshavewalls said:
			
		

> ...the state COULD tax it if .....


One property owner, sells the Electricity, to another property owner....


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## FyrBldgGuy (Apr 28, 2011)

Over the past couple of years I have been working with a municipal utility district that has been setting up more then one micro grid, and assisting others to do the same thing.  The point is a reduction in the need for generation and the DOE is putting billions of dollars out there to create these micro grids all over the country.

There will be entire subdivisions of houses on micro grids using solar and batteries.   The metering of public power will go through a central point and then sub metered.  Or at least that is one proposal.


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## earshavewalls (Apr 28, 2011)

After hashing this out over a few days, and many opinions, we have come to the conclusion that as long as the buildings are on the same property, under the same ownership and management, that we will consider a design submittal for this installation. I think there are some grounding issues and busbar sizing potential issues that will need to be addressed, depending on the design. I am putting the design on the owner and electrical engineer for this project. We'll take it from there.

Thanks for your inputs and opinions, that's what I come here for! This is a great place to "think outloud" and bounce ideas and interpretations off of people who deal with these issues on a daily basis, too.

Thanks again!


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