• Sonori@beehaw.org
    link
    fedilink
    arrow-up
    1
    ·
    7 months ago

    You need less on a social scale if everyone is interconnected obviously, but at the individual level it may well cost more. People were doing household scale off grid with a pile lead acid for decades after all.

    Households don’t necessarily need that much power, and while heat pumps change that up north in the winter, when it comes to modern day solar off grid you often use two to three times the inverting capacity worth of panel, precisely because it allows for reliable near full power generation on cloudy or snowy days.

    • silence7@slrpnk.netOPM
      link
      fedilink
      arrow-up
      2
      arrow-down
      1
      ·
      7 months ago

      I’ve lived with one of those systems:

      • it didn’t use the electricity for heating, cooling, refrigeration, water heating, or cooking
      • It was 12v electricity, so you had to have specialized lighting and other appliances to use it
      • you tended to have limited electricity available in the winter

      It’s not the same as the almost-always-available situation that people expect.

      • Sonori@beehaw.org
        link
        fedilink
        arrow-up
        2
        ·
        7 months ago

        So have I, and nowadays it very much is almost always available situation people expect, even for fully electrified homes. PV paneling cheaper per square m than fencepost plus being able to store a full weeks worth of average amarican home consumption for 20k of new battery have combined to make generatorless off grid a lot more practical.

        • silence7@slrpnk.netOPM
          link
          fedilink
          arrow-up
          1
          arrow-down
          1
          ·
          7 months ago

          Yes, if you’re not running HVAC in a northern climate. Those use enough electricity that grid-connection is incredibly valuable.

          • Sonori@beehaw.org
            link
            fedilink
            arrow-up
            2
            ·
            edit-2
            7 months ago

            Even then, modern heat pumps on average only use in the neighborhood of .5k to 2k kwh during the coldest months in southen Canada/ northern US, that is definitely within the capabilities of an reasonably affordable properly designed off grid solar system. Hence why I suggested it was reasonably doable for a fully electrified home, and will likely be much cheaper by the time your average lemmy user is building or buying their dream home.

            Currently such a system is already in the cost range of twice that of a inground pool, by far the two most expensive parts of it, overpanneling and battery storage are plummeting in cost.

            • silence7@slrpnk.netOPM
              link
              fedilink
              arrow-up
              1
              ·
              7 months ago

              I think you underestimate what it takes to heat an older structure in the north. 7kw is pretty common for whole-home retrofits. Enough to run that all night in winter during an extended cloudy spell means a lot more panels and a lot more storage.

              • Sonori@beehaw.org
                link
                fedilink
                arrow-up
                2
                ·
                7 months ago

                Are you suggesting a 7kw heat pump, or 7,000kwh/m highest hearing load? Because the former would already come out to about 2.5k kwh assuming a 12h duty cycle for 30 days, while the latter would cost over a thousand dollars a month to run at average US electricity prices during the month of highest load.

                For reference the typical heat pump in the typical amarican single family house consumes 5.4k kwh in an entire year.

                • silence7@slrpnk.netOPM
                  link
                  fedilink
                  arrow-up
                  1
                  ·
                  edit-2
                  7 months ago

                  the typical heat pump in the typical amarican single family house consumes 5.4k kwh in an entire year.

                  I think you googled, took the first result, which was:

                  https://www.energysage.com/electricity/house-watts/how-many-watts-does-an-air-source-heat-pump-use/

                  and it says “Based on an EnergySage analysis of a Department of Energy database, a typical heat pump in a typical home uses 5,475 kilowatt hours (kWh) per year”

                  but then treated it as meaning a “about 5½kwh” instead of 5475kwh.

                  The two are very different numbers, and most heat pumps in the US are currently installed in warmer locations, so you can expect utilization in colder places to be appreciably higher.

                  A heat pump won’t be running at peak output all year long, but during winter in the north, it’s likely to do so every night for a week at some point.

                  A $1000/month heating bill isn’t that rare in some parts of the US in winter.

                  • Sonori@beehaw.org
                    link
                    fedilink
                    arrow-up
                    3
                    ·
                    7 months ago

                    In most (sane) numbering systems, you can use a k in place of thousands, m in the place of millions, etc. Becuse all the numbers around the scale of energy use involving the entire monthly power consumption use of a heat pump in a cold climate as well as solar production and storage needed are in thousands, you will note I wrote all the relevant numbers with the abbreviation k, so 5,475 kwh is equivalent to 5.4k kwh.

                    Admittedly 5.4 mwh would have been more clear, but because megawatt hours is less commonly used and would involved useing two diffrent units next to each other I used thousands of the same unit for consistency. Please go back and re-read all of my comments with this new knowledge in mind.

                    Yes, many heat pumps are installed in warmer climates, though that is changing, but blowing through the entire yearly national average in three weeks and then doing it again is lot of power for a climate contentious and thusly presumably well insulated off grid modern house to use. (Also, if we go back to what this conversation is about, the original commenter gave no indication that they were in a very cold climate with thousand dollar a month heating costs in the first place.)