Comment on ‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

• Buffalox@lemmy.world ⁨15⁩ ⁨hours⁩ ago

  When we bought the house, that was one of the parameters on our list for “the perfect house”. So the roof to the garden is also almost perfectly towards the south. 😀
  Even in January we’ve made 41% of our power consumption from the solar panels. 😎 You are right that it is a bit oversized according to “normal” recommendations which are 8 kWh for a house the size of ours, but we went a bit bigger in preparation for air to water heat pump, so warming the house will be electric, (currently wood pellets), and also we plan to buy an electric car within the next 2 years.

  Also it was a bit for fun, because of the movie spinal tap, so our panels go to 11 instead of just 10, because we need that little bit extra. 😋

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  • Valmond@lemmy.world ⁨13⁩ ⁨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!

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    • Buffalox@lemmy.world ⁨11⁩ ⁨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.

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