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Elon's backup power vision

Discussion in 'Tesla Energy' started by Cosmacelf, Jun 9, 2015.

  1. Cosmacelf

    Cosmacelf Active Member

    Mar 6, 2013
    San Diego
    Did you guys catch Elon's description of how people would use a Powerwall in a backup scenario at the shareholder meeting?

    Most existing backup systems (either via a generator or a hybrid solar/battery system) have a "critical load" electrical panel. When grid power goes down, a transfer switch trips, isolating the critical load panel from the grid. The critical load panel is then fed power from the backup power source. The idea being that the backup power source can't feed the entire house, so only critical loads are fed (like freezers, refrigerators, some lights, etc.).

    However, when you have a solar panel system, the solar system typically generates more power than the entire house needs during the day.

    So Elon mentioned in passing today, a different way to arrange critical loads. He suggested that people with solar panels and an appropriate number of Powerwalls would instead have a non critical load panel which would be turned off in a power outage giving power to everything else in the house. So only power to non essential high power devices like air conditioners would be turned off.

    I picked up on this because this is exactly what I'm thinking of doing in the new house I'm going to build.

    In fact you could theoretically go a step further and have an energy monitoring program turn on and off non essential loads during power outages depending on the available power available from the solar/battery systems.
  2. electracity

    electracity Active Member

    Jun 8, 2015
    Automatic backup generators have been available for years, and shedding an AC (or only allowing one to run at a time) has been done for years.
  3. miimura

    miimura Active Member

    Aug 21, 2013
    Los Altos, CA
    The problem is that most "Smart" transfer switches are really dumb about load management. When I built my house I pre-wired for a permanently installed natural gas fueled generator, but installed my own automatic transfer switch. It is basically a 10 circuit A/B/C switch array with configurable Watt supply ratings for the generator and battery backup. You can individually configure each circuit as uninterruptible, generator always or generator fall-back. Since it measures the real-time amperage of each circuit and knows the capacity of the generator, it can do smart load shedding and round-robin power cycling so that things like refrigerators and freezers are guaranteed to be powered a certain number of minutes per hour.

    Since I never permitted and installed the generator, I'm now considering getting a off-grid inverter and salvaged EV pack to power the generator input of the transfer switch. Right now, I just have the structured wiring box (internet modem, router, ethernet switch, cellular booster, etc) and my home office powered from a conventional 1500VA UPS connected through the transfer switch and house wiring. The rest of the circuits just run from the grid.

    Buy APC Universal Transfer Switch 10-Circuit 120/240V - Technical Specifications and Information | APC

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