An innovative approach to making electricity from the wind
economist.com
economist.com
> Nor is it absolutely necessary that the electricity generation is done on the ground. Makani, a firm recently absorbed by Alphabet, Google’s parent company, has a different approach. It is lifting the generators into the sky, on board a pilotless aircraft with a wingspan of 26 metres. This craft has eight rotors, which act as propellers for take-off and landing. Once at operating altitude, however, they become miniature turbines. The electricity they generate (600 kilowatts at full capacity) is sent to the ground through a power line encased in a tether nearly half a kilometre long. Makani’s prototype has been tested in Hawaii and, later this year, a further series of tests from an oil platform off the coast of Norway are planned.
I'm excited to report that we really did pull off the offshore test a few months after this Economist story went to print.
Video of our recent offshore test: https://www.youtube.com/watch?v=F6NW0QeKLZA (I know it almost looks like a rendering, but it's for real!)
And a company blog entry about the test: https://medium.com/makani-blog/makanis-airborne-wind-power-s...
Makani was funded in part by ARPA-E earlier in its existence, and they recently also made a video about Makani that might be of interest: https://www.youtube.com/watch?v=C9Ly6na58e0
Edit: Ignore the following line. It is too early in the morning.
--A single one is producing 600KW, so you need a few per household, and many thousands for a town.--
See https://en.wikipedia.org/wiki/Kilowatt_hour#Confusion_of_kil...
Your car engine is rated in power (typically horsepower in the US, though kW is equivalent), your car fuel tank is rated in energy, that is kWh or joules.
Power determines how hard you can work. Energy determines for how long.
A big house running AC for a hour would give you a kWh number. The instantaneous load is measured in kW.
Their website explicitly says [2] (Overview 1.4):
> designed to transfer up to 600 kilowatts of electrical power—enough to power about 300 homes
Then I saw this: https://makanipower.com/makani/images/pages/technology/cta.j...
It doesn't need any exotic materials, and it scales up to unlimited size. Stretch a mesh between a pair of tall buildings, or between pylons of old, worn-out windmills, or, yes, across a kite.
Alvin Marks patented a version of it in the 80s.
He didn't say how to make the ions. Some materials spontaneously give up surface electrons to wind, so you might get away with streamers of the stuff tied where warp meets weft, if it is made slightly conductive.
With varying intensity I've been following renewable energy development for many years. I've seen many proposals for new forms of wind energy, many of them looking promising. Same for new forms of solar, new forms of water power and many other things. The Kite approach isn't new either.
However the reality is that the only thing that's been successful for wind energy is to do almost the same thing they've been doing in the past, just bigger, better and cheaper. The biggest efficiency win in wind energy is to build similar technology, just with bigger wings and larger towers. The biggest innovation was to bring costs down. Technology got better in the details, the basic "three blades that spin around" stayed the same.
I know this is pretty boring. But it's successful. I'd bet on "make wind energy cheaper and larger" more than on any fancy new tech.
I could be biased because I do not want to live in a world where we're mainly making incremental updates, but it seems like that's what it is.
That has driven offshore wind farms, kite turbines, and placement patterns such that turbines can be placed more closely together without stealing wind from each other.
[1] https://news.ycombinator.com/item?id=9222149
[2] https://www.newscientist.com/article/mg16722574-800-reach-fo...
For the stated generation model, the kite's lift is being directly used to create electricity as it is reeled out and in. For lofted generators (Google's power kites), you're putting the turbines and generators in the air. Both are more effective with kites than balloons, as in the first you get more lift providing generation directly, and in the second a far smaller wing can support a much larger weight than is possible with a balloon.
Frankly I don't think any of these approaches is very practical in the long term at scale. Too many fiddly bits.
To me, solar is first-order. Solar leads to wind, so it's second-order. (Though really, solar heats water and air, producing wind, so it's kinda third-order.) Oil is... uh... the sun grows the plants which die and get compacted, then we pump up the remnants. I'm not sure what you'd call that.
Uranium is, like, zeroth order then. Fusion in the Sun produces solar.
And yet, none of this really means much. Unless you're constructing Dyson spheres, it really doesn't matter how efficiently you're capturing the max theoretical energies. If you don't believe me, stop eating. Try replacing food with sucking on a power cord.
Solar, even concentrated desert solar, is no good at all. Wind is a distant derivative and much, much worse.
Hydrocarbons and nuclear are the fuels of today and tomorrow because they are orders of magnitude more energy dense. These energy sources are so dense they double as energy storage.
We need to get on nuclear. Then we can help poorer nations with nuclear power so they can undergo their own Clean Industrial Revolutions. In 80 years we all want the world’s ~11 billion plus people to live far better than we live in the West today.
I'm in favor of nuclear power too, but it takes too long to build.
That's far from solved, countries close to each other have very similar weather pattern and wind electricity is especially unreliable. We're also very unlikely to have a massive breakthrough in turbines since we're close to the theoretical maximum already.
Wind turbines obey Betz's law https://en.wikipedia.org/wiki/Betz%27s_law and are already close to maximum efficiency, the only thing you can do is drop the production cost.
Depending on the region, seasonal differences caused by low wind are canceled out by higher solar production and low solar production is canceled out by higher wind production. That chart completely fails at showing that.
Experts wrote thick reports on how to transition to renewables. You shouldn't dismiss their work with half a dozen graphics on Twitter.
> Each siting location by definition is worse than the one before.
How is that not true for nuclear power plants? If we have better tech, we can remove old panels and wind turbines. With nuclear plants the place is lost forever. Let alone that there cannot be a safe place to store the waste.
I'm a LFTR fan. Solar wind has won and civilization should concentrate on enabling it to eliminate gas/coal from our energy production.
Nuclear has a higher energy density than hydrocarbons or batteries but we still don't see nuclear powered cars and aircraft everywhere.
Wind, though a 2nd-order form of solar energy, concentrates at some points on the surface. Since both forms work by way of building some form of collection capital and recovering energy, wind allows a higher site-specific EROEI than solar, given favourable siting. Not in all locations, but in some.
That's why wind power makes sense.
Though I'm skeptical of airborne / kite-based generation.