Solar plant for Multi tenant Building

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yducerf

Member
Location
france
Hi , in advance sorry for my English , i'm just french ;-)

My project is to Install a photovoltaic system on a multi-tenant building roof..

My objective is to balance the PV production between all tenants .. each tenant could consume solar power , and when many tenant consume , all consume the same quantity of green power.. but each can consume the rest of electricity on the grid

Do you think it's possible ? perhaps with a battery system's..

Do you have an idea ???
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
It does not seem practical to me to feed a controlled amount of PV generated power to each tenant except by using individual grid tie inverters with individual sets of panels for each tenant. And I don't think that will be practical.

But since the electrons do not know what their power source is you could run a large grid tie system with a production meter and simply divide the output by the number of units and pay an equal credit towards their individual electric bills.
Similar to the way green and non-green power sources are mixed together into the distribution system and customers can choose to buy one or the other simply as accounting fiction.

You do not want to do anything with batteries as that will multiply the cost of the RE power by at least a factor of two. Storage technology is not good enough yet.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
My objective is to balance the PV production between all tenants ..
Where is the power company's electric meter? Does each tenant have their own meter, or is the entire building connected to a single electric meter?
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Hi , in advance sorry for my English , i'm just french ;-)

My project is to Install a photovoltaic system on a multi-tenant building roof..

My objective is to balance the PV production between all tenants .. each tenant could consume solar power , and when many tenant consume , all consume the same quantity of green power.. but each can consume the rest of electricity on the grid

Do you think it's possible ? perhaps with a battery system's..

Do you have an idea ???
I agree with GoldDigger; batteries are right out for this application. Also, as Al has mentioned, it makes a big difference if each tenant has his own meter or if there is one meter for the building. If each tenant is separately metered then each will need his own inverter(s) and interconnection to see the benefits individually, and that could be cost prohibitive.
 

ron

Senior Member
Electrons are dumb. They go to were the load draws them.

If you connect at the main service disconnect, then everyone has access to those wonderful electrons, without messing up anyone's particular individual meter for energy recording.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Maybe I am under thinking this.

If the object is to split the solar production evenly with each tenant, why not just meter the total solar and divide by the number of tenants and bill them accordingly?

Am I missing something that would prevent this, or is this not what the OP is looking for?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
In California there is something called 'Virtual Net Metering' by which the solar system is connected to a single new utility meter, and the credit for production is divided among the tenants according to a pre-agreed ratio. Not many people have done it because of the costs of adding the new meter.

If all the tenants have separate meters, then unless France has a similar policy option I don't see what you have in mind as viable.
 

Smart $

Esteemed Member
Location
Ohio
Just connect the system into the building service ahead of any tenant metering. Work with the POCO to determine the best metering scenario.

Essentially t-tap into service, and as Ron pointed out, it'll go wherever the load draws it.
 

yducerf

Member
Location
france
I agree with GoldDigger; batteries are right out for this application. Also, as Al has mentioned, it makes a big difference if each tenant has his own meter or if there is one meter for the building. If each tenant is separately metered then each will need his own inverter(s) and interconnection to see the benefits individually, and that could be cost prohibitive.
Why is it cost prohibitive ?
Is there a UPS with multiple AC outputs ?A solution with micro inverters ?
TIA
 

iwire

Moderator
Staff member
Location
Massachusetts
Why is it cost prohibitive ?
Is there a UPS with multiple AC outputs ?A solution with micro inverters ?
TIA

Unless you live off the grid batteries are at this point not feasible.

The cost of purchase and upkeep will exceed any power company savings you may get from the batteries.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
In California there is something called 'Virtual Net Metering' by which the solar system is connected to a single new utility meter, and the credit for production is divided among the tenants according to a pre-agreed ratio. Not many people have done it because of the costs of adding the new meter.

If all the tenants have separate meters, then unless France has a similar policy option I don't see what you have in mind as viable.

Since every tenant is metered, the ratio should be based on the square footage leased by each tenant compared to the building as a whole.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Why is it cost prohibitive ?
Is there a UPS with multiple AC outputs ?A solution with micro inverters ?
TIA

A UPS (battery backup) and a grid tied PV system are different animals. UPS is for bridging power outages and GT PV is for offsetting power company charges. You can build systems that do both but they are expensive, and you cannot do it with microinverters. A UPS with multiple outputs won't work because no utility is going to allow you to interconnect a single system with multiple meters.

GT PV using microinverters might be a solution for you, but if you don't have a central meter before the tenant meters you will either have to build a separate system with its own interconnection for each tenant or you'll have to work out with the utility some way to interconnect outside the meters. Something else you would need to check out if you build a single system is how the utility feels about your reselling power to your tenants.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Since every tenant is metered, the ratio should be based on the square footage leased by each tenant compared to the building as a whole.

It makes more sense to base it on past electricity usage. But legally it can be done however you want. If one tenant wants to pay for a higher proportion of the system they can get a larger portion of the credits.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
A solution with micro inverters ?

If there are less than, say, 10 units then installing separate systems to each meter might be more cost effective than something like virtual net metering. If there are, say, 60 units then it's kind of ridiculous, and costly, to run 60 circuits to the roof.
 
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