4 ms·

First of all, do not rely on that site to provide you accurate, unbiased advice. They have an agenda, and they are pushing it. Second, there is a huge differen

by D_Alex 7y ago

First of all, do not rely on that site to provide you accurate, unbiased advice. They have an agenda, and they are pushing it. Second, there is a huge difference between using small wind turbines in the city, where the alternative is reliable and cheap grid power, and off grid, where the alternative is increased use of expensive and unreliable small diesel generator. Whether a small wind turbine is worthwhile for an off grid system depends on lots of things, primarily on availability of solar, availability of wind an your usage pattern.

benj111 7y ago
Everyone has an agenda, that doesn't mean you can discount what they say. Now if you want to point out which bits are inaccurate? Then we can have a discussion on the merits.
- inflatableDodo 7y ago
  >Many commercially available small wind turbines with plastic blades and steel towers are infamous for their low reliability, high embodied energy, and limited power output. >Building them out of wood addresses these issues. Well, wood isn't going to improve the reliability or power output. It can be significantly less embodied energy per blade, depending on construction however. A blade hand carved from a single piece of air dried timber has a lot less embodied energy than a blade made from laminated wood covered in resin, which in turn has less embodied energy than a fiberglass blade, though it isn't as big of a jump in percentage terms than it is from air dried timber to laminated timber. That said, as you go smaller, the blade itself is less of the embodied energy of the wind turbine. On the small turbines that used to be common on yachts, the blades are really a minor part of the construction, the generator and the pole weigh in far higher. Also, given that turbines are a swept area game, I suspect that using hand carved wooden blades only saves you anything in situations where you cannot have larger blades. Also, they will tend to be less efficient blades in terms of power conversion due to the limits of hand carving. If you are interested in the best thing environmentally, clubbing together with others to install the largest turbine you can is still generally the way forward. If that is not possible then I'd say hand carved wooden blades do have a place on small tubines, though I am doubtful it is that environmentally beneficial, unless you have scavenged the other parts. Scavenging the parts for small turbines is perfectly doable though. Personally, if I was scavenging already, I would be also looking at cutting out blades from scrap metal sheet. edit - blades from scrap metal being a hell of a lot quicker to fabricate than hand carving wood.
  - benj111 7y ago
    You don't have to hand carve blades. As far as I understand it wooden propellers were pretty close to optimal, I don't see why turbine blades would be different The article does mention one turbine optimised to run at lower speeds, which might be the increased reliability mentioned, but no it doesn't explain the power output. I'd tend to put that down to poor writing / and artifact of a previous draft, so I still don't think it's enough to write off the entire article, website and writer. The author's article on small turbines not generating their own embodied energy was what first made me aware of that 'issue'. This is an attempted fix. I agree with you that the best solution is to go bigger, still the proposed options, particularly the pole seem sensible even on a village sized turbine.
    - inflatableDodo 7y ago
      Definitely do not write them off. I find the site useful and check in now and again, but I read it with a very large pinch of salt.
      - benj111 7y ago
        True enough, I would recommend the same for any publication though.
- brohee 7y ago
  The main issue with that site, is that every time numbers are involved they are wrong, often by an order of magnitude... Here one wildly optimistic number is kWh/year on the 10kW turbine, but I suspect the energy cost of building a fiberglass/epoxy blade is wildly off too...
  - benj111 7y ago
    "According to the manufacturer...... produce roughly 30,000 kWh of electricity per year" That works out to a capacity factor of 35% which doesn't seem shockingly high. https://cleantechnica.com/2012/07/27/wind-turbine-net-capacity-factor-50-the-new-normal/ https://cleantechnica.com/2012/07/27/wind-turbine-net-capaci...
deleted 7y ago
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by D_Alex 7y ago

benj111 7y ago

Everyone has an agenda, that doesn't mean you can discount what they say. Now if you want to point out which bits are inaccurate? Then we can have a discussion on the merits.

inflatableDodo 7y ago
>Many commercially available small wind turbines with plastic blades and steel towers are infamous for their low reliability, high embodied energy, and limited power output. >Building them out of wood addresses these issues. Well, wood isn't going to improve the reliability or power output. It can be significantly less embodied energy per blade, depending on construction however. A blade hand carved from a single piece of air dried timber has a lot less embodied energy than a blade made from laminated wood covered in resin, which in turn has less embodied energy than a fiberglass blade, though it isn't as big of a jump in percentage terms than it is from air dried timber to laminated timber. That said, as you go smaller, the blade itself is less of the embodied energy of the wind turbine. On the small turbines that used to be common on yachts, the blades are really a minor part of the construction, the generator and the pole weigh in far higher. Also, given that turbines are a swept area game, I suspect that using hand carved wooden blades only saves you anything in situations where you cannot have larger blades. Also, they will tend to be less efficient blades in terms of power conversion due to the limits of hand carving. If you are interested in the best thing environmentally, clubbing together with others to install the largest turbine you can is still generally the way forward. If that is not possible then I'd say hand carved wooden blades do have a place on small tubines, though I am doubtful it is that environmentally beneficial, unless you have scavenged the other parts. Scavenging the parts for small turbines is perfectly doable though. Personally, if I was scavenging already, I would be also looking at cutting out blades from scrap metal sheet. edit - blades from scrap metal being a hell of a lot quicker to fabricate than hand carving wood.
- benj111 7y ago
  You don't have to hand carve blades. As far as I understand it wooden propellers were pretty close to optimal, I don't see why turbine blades would be different The article does mention one turbine optimised to run at lower speeds, which might be the increased reliability mentioned, but no it doesn't explain the power output. I'd tend to put that down to poor writing / and artifact of a previous draft, so I still don't think it's enough to write off the entire article, website and writer. The author's article on small turbines not generating their own embodied energy was what first made me aware of that 'issue'. This is an attempted fix. I agree with you that the best solution is to go bigger, still the proposed options, particularly the pole seem sensible even on a village sized turbine.
  - inflatableDodo 7y ago
    Definitely do not write them off. I find the site useful and check in now and again, but I read it with a very large pinch of salt.
    - benj111 7y ago
      True enough, I would recommend the same for any publication though.
brohee 7y ago
The main issue with that site, is that every time numbers are involved they are wrong, often by an order of magnitude... Here one wildly optimistic number is kWh/year on the 10kW turbine, but I suspect the energy cost of building a fiberglass/epoxy blade is wildly off too...
- benj111 7y ago
  "According to the manufacturer...... produce roughly 30,000 kWh of electricity per year" That works out to a capacity factor of 35% which doesn't seem shockingly high. https://cleantechnica.com/2012/07/27/wind-turbine-net-capacity-factor-50-the-new-normal/ https://cleantechnica.com/2012/07/27/wind-turbine-net-capaci...

deleted 7y ago

[deleted]