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What to do with unused energy?

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  • #16

    Re: What to do with unused energy?

    Re: What to do with unused energy?

    I admit I am not a close follower of NEC code, but are you saying there is currently no legal way to use microinverters on RVs to backfeed a plug-in grid connection?

    As far as I can tell the existing RV plug-in (with all intervening plugs) can be used for backfeeding, as long as they are locking connector(s) and "a tool" is required for disconnect. Enphase is arguing against these restrictions for the next code iteration http://enphase.com/wp-uploads/enphas...Connectors.pdf

    No doubt there will be some clarification of the issue when plug-in cars become common, and hackerillas start tapping the revenue from their load-shifting capability.


    • #17

      Re: What to do with unused energy?

      Re: What to do with unused energy?
      1. You need building inspector approval--There is no way you can parallel energy sources via standard plugs that do not add current to a branch circuit that is safe (or legal). You have a 15 amp branch circuit, plug in upwards of 15 amps of GT Inverters. Now that 15 amp branch circuit has 30 amps available in a short circuit.
      2. Typically Utilities are required to inspect/check for insurance/grant approval. Since there cannot be a UL/NRTL approved "plug in" GT inverter, they can never grant approval.
      3. Solar panels need to be safely attached to the roof (structural).
      4. Solar panels/GT Inverters need to be safely wired into the home/business in such a way that home wiring does not get over heated (correct sized panels/wiring) and that proper material/equipment is used (UL/NRTL approved materials).
      5. Utilities are replacing meters with ones that either do not turn backwards (you cannot get paid for your power) or even turn forward no matter which way the power flows (you actually will get charged for generating energy to the grid).
      6. Utilities are keeping track of who is generating power. In California, the utility only has to allow 1% of power to be generated by "small generators". My guess is by 10% worth of small generators, the grid will become unstable and new technologies (central control of GT inverters) would be required.
      7. As more people install GT systems--they can actually exceed the local grid's ability to handle the increase in current (flowing the "wrong" direction). Quebec is now preventing new installs for (last I read) not very clearly defined reasons (local grid capacity?).
      8. Most net metered setups do not make economic sense for the utility--Buying power back at retail and selling it again at retail just does not make sense. In California, about 1/2 the cost of power is generation, and the rest is cost of distribution, billing, repairs, running a company, etc.
      Is that to say that you placing a small 200 watt unapproved GT inverter+panel in your RV is going to blow up your corner of the world.... Not really.

      At this point, I do not see people actively time shifting power using the electric cars. It does not make economic sense because the cost of wearing out the batteries usually exceeds the savings from shifting power (at least at my TOU billing levels).

      Some countries have already made battery connected GT inverter systems illegal already (I guess, so they cannot buy cheap power at night and sell it during the day).

      Is it safe--No idea. Too many variables.

      Panel Fire Question

      20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.