
Reinventing the Small Wind Turbine - Red_Tarsius
https://www.lowtechmagazine.com/2019/06/small-wooden-wind-turbines.html
======
wespad
My favorite Hacker News story of all time, about a guy who builds a small,
water turbine power plant:

[https://news.ycombinator.com/item?id=6895582](https://news.ycombinator.com/item?id=6895582)

[https://ludens.cl/paradise/turbine/turbine.html](https://ludens.cl/paradise/turbine/turbine.html)

~~~
esaym
Good night I just wasted so much time...

~~~
mlpinit
And that makes two of us...

------
burlesona
The article is called "reinventing the small wind turbine," by which I think
they meant "redesigning from plastic/fiberglass to wood."

What I was hoping is that they'd talk about how common small-scale generation
was a hundred years ago.

We're gradually getting back to where things were headed in the 1920's before
the Rural Electrification Act essentially killed the local generation
industry.

If you're interested, there's a relatively quick primer on that history here:
[http://www.windcharger.org/Wind_Charger/Farm_Electric.html](http://www.windcharger.org/Wind_Charger/Farm_Electric.html)

~~~
agumonkey
Not sure if I'm imagining things but I see this pattern of oscillating between
distribution (small scale local) and integration (large remote). In computer
we had a bit of the same (mainframe -> desktop -> servers -> smartphones ->
consoles -> streaming from datacenter). It seems a 'natural' phenomenon of
optimization.

~~~
stareatgoats
Could be seen as an expression of dialectic development. The overall tendency
in many (most?) living systems is towards integration at the next scale, which
needs a certain amount of centralization. But whenever centralization is
imposed it is usually overkill (the pendulum swings too far), which causes a
decentralization effort (back to the autonomy of the parts), that however will
retain some remnant of the previous centralization drive. At a certain point
the decentralization swings too far too, and so centralization takes place
again, in a slightly different way this time.

The combined effect of these oscillations is an equilibrium between
centralization and decentralization of the organism which is optimally adapted
to the environment at that scale of integration. Which is why neither
centralization nor decentralization are ideals, they are both needed in an
evolutionary process, albeit at different times.

~~~
agumonkey
I definitely see some pendulum effect scattered through the field.

Maybe there's a sensory about system pressure (need for more bandwidth, or
whatever) that when above a certain threshold trigger that swing change.

------
kstenerud
I'm being a bit pedantic here, but they are too, so let's consider:

They argue that wooden blades are less energy intensive to produce, which is
technically true if you discount the amount of energy to grow the wood in the
first place. What we're actually talking about is additional energy cost over
the initial sunk costs of the wood (which don't really matter to us). This
part is mostly trivia, but it ties into another point:

What are we actually worried about here? We're worried about unbalancing our
ecosystem, and additional energy expenditure is assumed to not be supplied by
renewable energy sources (which is generally true today). So our fundamental
concern is the release of greenhouse gases (due to burning of fossil fuels in
order generate energy for production).

The calculation then becomes: What is the cost in greenhouse gases of cutting
down trees to produce turbines? Trees are carbon absorbents and carbon sinks,
after all. What is the cost in greenhouse gases of feeding the people who
expend their vital energy to produce the wooden turbines? How does that cost
compare to production using robots? How does that cost compare to production
using synthetic materials? Does that calculation change enough to matter as
the source of energy moves more towards renewables?

What I'm getting at is: Where is the actual CO2 bottleneck in production? We
should be optimizing the bottlenecks first.

------
Animats
This is kind of neat, but the fascination with wood blades is like wanting
something to be "organic".

The article claims getting 30,000 KWh/year from a 10KW wind turbine. That's
optimistic. Burgey, one of the larger makers of 10KW wind turbines, only
claims 13,800 KWh/year. There's a standardized way of measuring this, with
reasonable wind speed values. Few places have an average wind speed of 15 MPH
near ground level. (And you don't want to live there.) That guy on the
Scottish coast mentioned in the article might get that.

Compare a commercial 10KW wind turbine.[1] Costs about the same, about US$40K,
plus installation and tower. 10 year warranty. (Wind speeds above 135mph void
the warranty.) "Designed for high reliability, low maintenance, and automatic
operation in adverse weather conditions." Which is the real problem with wind
turbines - surviving adverse conditions.

[1] [http://bergey.com/products/wind-turbines/10kw-bergey-
excel](http://bergey.com/products/wind-turbines/10kw-bergey-excel)

------
csours
The last time I read about localized power on HN, storage came up, esp
batteries and inverters.

The majority of appliances now assume always on, very clean, 60hz (or 50 or X)
power, because that's what the turbines at the power company have always made.

What assumptions would have to change for appliances and human life to fit
with localized generation? (Ie off-grid living)

~~~
sliken
Generally most consumer equipment in the last decade or two is pretty flexible
on voltage. The modern switched power supplies are both flexible and
efficient.

But generally equipment is AC, and solar and batteries are DC. So it's
entirely up to your inverter how clean your power is.

But generally off the grid users have to either over build a crazy amount
(which is expensive) or adapt a bit. Things like hanging laundry vs using a
clothes dryer might not always be necessary, but if the wind/solar is behind
it would be a good investment.

Even things like dressing for summer instead of blasting the AC so you can
wear multiple layers can make a huge difference. If you have a surplus during
the day (which is common with solar), run your most power intensive stuff
then. That way your very expensive batteries don't have as much load to make
it through the night.

Things like air conditioning are among the hardest loads, high peaks, worst
when it's hot, and overall just a huge amount of power. Who wants to pay $40k
for batteries instead of just being a bit smarter with insulation, whole house
fans, and dressing for the weather? In my city I'm often out in about after
midnight, with a light jacket on, and listening to neighbors AC blasting with
all their windows closed while their AC fights the thermal mass in their
attic. Seems insane to not open the windows when it's under 60F.

Generally minor changes. You can still stay up all night watching tv, still
have a comfortable life pretty close to normal. But if you don't adapt you
might be out of luck a few days a year or have to spend 2-3x the money.

~~~
adrianN
All the things you mention would save 2-3x the money with a normal grid
connection too, it's just that energy is much too cheap for people to care.
Thus 10kW of continuous primary power consumption for each American.

~~~
sliken
Agreed. However on the grid running a dryer instead of hanging clothes isn't
much difference in money to most Americans. Off the grid the difference in
batteries+solar/wind is huge.

------
gandalfian
My family have a 5kw turbine (UK). About 12,000kw a year. £30,000, with the
help of heavy government subsidies it makes about 7% return a year, including
loss of capital, if it lasts twenty years. As soon as subsidies ended industry
shut down. Without subsidies the servicing and repair costs wipe out most of
the savings leaving with you with a few hundred a year if lucky. I don't think
anyone is going to buy another small one any time soon... Low maintenance
solar has won, the wind turbines firms all closed themselves or went bust.

What would transform it? If someone like Honda mass produced cheap turbines
with Honda reliability with a proper eco system of servicing, parts and repair
knowledge. That would make a big difference. Changing the adequate fibreglass
blades for wood? Not really. I can't see getting a hand carved blade made
being a cheap repair. Government caused boom and bust is not helpful.

And obviously cheap batteries but that would transform everything too...

------
cellularmitosis
My favorite open source hardware project:
[https://www.otherpower.com](https://www.otherpower.com)

------
jacquesm
If you're into this stuff look at
[https://www.otherpower.com/](https://www.otherpower.com/), run by Dan&Dan,
two windmill enthusiasts from Ft. Collins, Colorado (They funded the forum and
all of their development through the sale of Neodymium magnets!).

Small wind turbines are - when done properly - some of the most complex
mechanical devices that you can still make at home and they will serve you
well if you are located off-grid. On grid they don't make much sense, neither
economically nor from a safety or reliability perspective.

Also keep in mind that you can't just rely on wind or solar for your energy
generation, you will need some of both, a battery pack for storage and an
inverter to connect to your distribution panel if you intend to power your
house.

A practical minimum power level for a home is somewhere between 1 and 2 KW,
but you're going to have to forego some luxuries.

------
chris_wot
lol, some guy called Phil wrote in the comments:

 _If you hand carve a blade, you still have to get energy from eating food to
power the human. So calling it "zero" energy used is bad accounting/
misleading._

Someone called whateveryoneisthinking wrote:

 _shut up Phil_

All comments are moderated...

------
adamcharnock
I was just researching wind turbines for my off grid system today, and then
this comes up!

I had been concluding that small wind turbines probably were not worth it. But
this addresses some environmental concerns and also makes it into a really
nice project (even if it still isn’t too efficient).

~~~
D_Alex
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
_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
>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
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
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
True enough, I would recommend the same for any publication though.

------
dev_dull
This is really amazing. I wish these were more practical on single-family
homes. I don't think my bay area city would ever allow me to put one up, so
it's solar.

------
LastZactionHero
I love this. Building a small wind turbine from as scratch as possible has
been a fantasy project of mine for years.

------
scotty79
Why fiberglass plastic and not steel?

~~~
rotten
Weight. In order to start the turbine spinning at the lowest possible wind
speed (meaning it will spin more often) it helps for the blades to be as light
as possible. There are other factors involved in getting the blades to spin,
but that is an important one. (other factors include the size of the magnets
in the coil, the shape and length of the blades, whether it is initially
pointing into the wind or not - and how much it takes to turn it into that
breeze - and so on).

