Announcement

Collapse
No announcement yet.

Where does it go?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Where does it go?

    First, apologies for my lack of knowledge about electricity and solar panels.
    Recently our school won a 3kw solar system (Solar edge) with a Tesla battery included.
    The local power company inquired about the best location and it was eventually installed on the roof nearest the outdoor pool.
    All well so far except that they didn't tell me that because it was on a switchboard that was off the main board we would not be able to sell back any extra power.
    I finally found this out after replacing the meter twice because it was not registering any power being exported.
    It appears to be a blessing as our electricity provider only buys at 8c and sells at 17c so we are probably better off consuming the extra in-house.
    Now my question is, if the system shows that it is exporting electricity and it can't see the 2 way meter where does the electricity go?
    Does it charge the battery or is it used by the system anyway?

    Thanks in advance.

  • #2
    Going to need a lot more details here.
    What system models do you have?
    whar state and what utility?
    it sounds like it is configured to not export. A 3kw system is really tiny for a school so not likely to export too much any way.
    do you have the single line drawing used for the permit!
    OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

    Comment


    • #3
      I agree. If the limited system is showing a net export but the main 2-way meter is not seeing any export it is simply because the "exported" power is being used elsewhere on campus and is offsetting what would otherwise be an additional purchase of that amount.
      I see nothing whatsoever wrong with connecting to a subpanel. You just get a different set of numbers than you expected and need to know how to interpret them.
      As you said, you will actually benefit from using all of the produced power, instead of selling some back and at the same time buying an equal amount at a higher price.
      SunnyBoy 3000 US, 18 BP Solar 175B panels.

      Comment


      • #4
        Is the OP aware of the SolarEdge monitoring portal?

        For example (note that public view hides consumption):
        https://monitoringpublic.solaredge.c...Hit#/dashboard

        Has SolarEdge consumption and storage (is this an AC or DC Tesla Powerwall? StorEdge inverter?) been configured on the the inverter and setup in the portal? If so, you would be able to see PV generation, and power flow (from solar into storage, out from storage, into the "grid" -- which is really just the rest of your building).

        The amount of power that a 3kW system makes is so small compared to what a school would consume (HVAC, pool, even just lighting, etc.) as others have said, it's very unlikely that net energy flow would ever favor export to the actual grid. Hence no kWh showing up on the export meter. Do you have access to your school's electric bill? How many kWh does your school use on a daily basis? Copare this to the expected PV kWh from a 3kW system using PVWatts.org or the SolarEdge Site Designer tool.

        How many solar panels? Did your utility company run this promotion and do the install? Or was it through Tesla, SolarEdge, or a 3rd party solar installer? Just curious for a few reasons:

        1) I've not heard of utility companies getting into the actual solar installs, I'd suspect there's a 3rd party local installer who would know more about the system -- which did the paperwork, engineering diagrams, permitting, etc.

        2) That's a lot of effort to setup such a small system -- especially for a commercial property like a school -- but free is good (-:

        3) What a great teaching tool. I would focus your efforts on turning this project into an instructional aid and demonstrative teaching tool. Practically speaking, a 3kW system is not really going to save you any appreciable money on something as large as a school's electric bill. For example, most houses in the US with solar have ~4 to ~8kW systems, with some as large as 10-15kW. Commercial systems are usually 15kW and up (10's, 100's, or 1000's of kW). For example we have a 1.5 Megawatt system at my workplace which offsets maybe 10% of our usage -- granted our campus consists of several buildings and labs each of which is as larger or larger than a single school.

        4) I'd love to apply for something similar for my school district. The kids would love it. My sons were so excited and interested in our residential system when we had it installed

        Best!

        Comment


        • #5
          I expect that a 3 KW system is barely a blip when it come to school load. There are all sort of always on systems like emergency lights, phone systems, fire alarm panels. laser jet printers and mechanical systems that pull power 24/7. Too bad you couldn't hook into a circuit that had some highly visible loads like vending machines. Think of the learning experience when after a couple days of clouds, the vending machines do not work as there isn't enough power.

          Comment

          Working...
          X