• Valmond@lemmy.world
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    23 hours ago

    Smart planning! Thanks for the story, are you planning to go off grid or is it just to be economically free? Any batteries in the future? Excellent reference, and implementation, I’m giving you an 11 out of ten!

    • Buffalox@lemmy.world
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      21 hours ago

      Thanks. 😀
      Going off grid was absolutely a consideration, but only for a very short while. There are too many downsides. We would need twice as much solar capacity, and a way bigger battery, and batteries are still pretty expensive, but even with that, we would still need a generator. And we wouldn’t be able to sell surplus energy. It would more than double the cost, and only provide 25% better self sufficiency for the whole year than we have now.
      We live in Denmark, and we can risk to have to go through almost all of December with only a few days sun. Running a diesel generator for power would be both noisy and smelly, It would also require more work to maintain, and it would actually cost slightly more to us a generator than to simply buy the electricity from the grid.

      Remember doubling our capacity will not bring us from 41 to 82% self sufficiency. Because there is some loss in storage, and even double our battery capacity would not be enough to store 48 kWh like we made today in the span of only 7 hours. (Today was the best day of the year yet. 😎)
      Even in January on a perfect day, we can make twice what we use, but such days are rare in January. (we use about 15 kWh per day.)

      The final problem with a generator is that we would never be able to achieve remotely the stability we have with the grid. We’ve been living here for 6½ year, and the power has only been out once!!!

      The problem with making it bigger than we have at all, is that after you’ve reached a point of above 50% self sufficiency, you are entering the area of diminishing returns quickly. On a yearly basis we are about 72% self sufficient. To reach that extra 22% probably cost 50% extra.

      This is if you live as high north as we do, because the extra capacity is only usable in the winter, in the summer it’s all surplus, and you get so little for selling the power it’s basically irrelevant. There is too much solar now, so when solar panels have high yields, prices often go down to almost zero.

      Going off grid is a lot easier if you live further south.