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Joined 11 months ago
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Cake day: November 28th, 2023

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  • It was more the relation between them (40x) that struck me as bigger than I expected given the relative performance between photovoltaic and photosynthetic efficiency.

    If they compare 1-year crops for human consumption, there will be a lot of tilling, sowing etc. but then we compare two different use cases with different purposes.

    Wood intended for burning for district heating, where the heat is taken care of with high efficiency, would be an energy usage more akin to electricity. In that case I would expect the harvesting and transportation part to be different.

    As a swede, energy usage in the winter is warm at heart which is something that is hard to compare and muddles the numbers. In Dec-Jan energy (kWh) output from solar is at best 9-10% of their peak output during summer at my latitudes, (further north, this goes towards zero as there is no sunlight in winter), so with that in mind, the stored 20MWh/hectare, available round the clock, looks apetizing until we find a better solution to store energy.



  • Aye, it corresponds with the numbers I’ve seen for photosynthesis efficiency as well. However, and here I believe we return to the root of the discussion, A: vertical solar panels in a field of crops both produce electricity and increase crop output (due to heat shelter and better moisture retention) and B: solar isn’t abundant during winter, so we need some sort of energy storage and biomass is pretty good at that.

    So, while it is not enough to offset that 40x, it will go a pretty long way of evening things out. Besides, if we produce more electricity than what is needed, the final solution, today, is to lower a heating coil into the ocean to burn off excess electricity. We will need to find energy users at the same pace we install solar, so leaving some ground for crops might not be a bad idea.

    As for the energy plan, it’s a requirement in the EED, it’s the same here.


  • I’m learning a lot about energy in Germany this way. Thanks! So basically farmers in Germany grow food to make fuel for cars? Like ethanol? Thats an abundance of agricultural lands!

    Pumped hydro is great, but will only cover that much energy. Of course, there are no alps in the Nordics, but even so.

    The batteries available today cover the need for an hour of the city they are situated in. That’s not enough. So for seasonal storage you’d need to store energy as heat, as chemical energy (wood/methanol) or as H2/bio, which I think is what you describe. H2 has much of the problems of batteries in terms of storage space and the risk of fires/explosions, which limits the possibilities somewhat. But if I’ve understood correctly from the TEN-T directive, Germany and Switzerland has invested pretty much in H2?

    Heat pumps are great, and are indeed well used, they run out of steam when its below -5C, which isn’t rare up here. And it’s seldom used in cities. Heat pumps collecting hear from the bedrock (through a drilled 100m hole in the ground) is more common, but most common is district heating. (I got the name wrong in translation earlier)

    Instead of one boiler in every house, there is one boiler per 50-100000 inhabitants or so. Efficiency is great and heat is pipes to where it is used. When it’s cold (-20 or so) those boilers go through tens of semitrucks of wood every day. And as I said, it’s a fairly common set up in parts of Europe, although i understand its not common i Germany.


  • That’s a whole lot of extra steps you added there. Why not simply go harvest -> burn for heat. It’s not complicated and it’s been done for the last 10000 years or so😊

    As for energy storage: Electricity can not practically be stored between seasons. Wood can. So sunlight from summer will not be able to power a EV in winter, but it will heat your home. And it is a way better solution than trying to produce electricity to heat your home, even if it’s just recycling CO2. At least it will not add CO2, unlike the coal that would have been used instead.

    68 million Europeans heat their home with some kind of central heating system. It not common in west, or central Europe, but it is in the Nordics and in the eastern part. Energy forests will be important going forward.





  • Oh, i see😊 When the EED takes effect in 2025/2026 id wager the return will be better for that use than solar panels, as all public buildings will be fitted with some sort of solar capture. Wood is a great energy store, as well, which we need more of.

    Oh, and in roughly the same time frame the steps of mandatory mixing of renewable sources in central heating will start, so such agricultural land will be economically more important.


  • Could be a difference in availability of land, but in Sweden you’d not be granted permission for something as mundane as a solar farm if it meant taking farmland out of production.

    As for the forests… That’s my greatest fear, that climate change will kill off large swathes of Oxygen producers by increasing ocean temperatures or making trees unable to thrive!

    How is agricultural land defined if it isn’t used to grow biomass?


  • On the contrary, I’m afraid. Land is in very short supply. The issue is that even if the land is not currently developed it is doing vital stuff already. If it’s used for food production, if it’s a bit of forest storing massive amounts of CO2, if it’s home the insects pollinating our food supply, if it’s…

    Finding scrap pieces of land, like roof tops/already developed land for solar will be crucial going forward.