Direct link to video for those frustrated by the scrolling: https://www.youtube.com/watch?v=GSYMHzgLLn8&t=20
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Google Makani – Wind Energy Kites
141–150 of 165 posts
Re: Google Makani – Wind Energy Kites
#142Earlier quoted context omitted.
A MILLION pounds (which really should be said in a "Dr Evil" voice :-)) is 500 tons. A rail car carries 120 tons of coal. A typical 2 GWe thermal plant burns a rail car of coal every ~20 minutes (coal has ~30 MJ/kg, and there are ~1000 kg/ton, so 120 1000 30E6 = 3.6E12 J/rail car, and 2 GWe ~ 4 GWth, which over 1000 seconds = 4E12 J) So by your figures, a windmill's yearly output is equivalent to a little over an hou…
I don't understand the focus on how many windmills it takes to replace one coal plant. It's not like there's some limit to how many you can build. If the costs are comparable, that's what matters, no?
At a certain level it actually does matter. The sustainability of a power resource is measured in many ways, even if CO_2 emissions is the most widely touted. Measures like water use, construction cost/emissions, and land use are significant. The number of windmills being built _does_ have an upper bound, dictated by some combination of land requirement and material availability. Of late, for example, the desire for high-output synchronous turbines has been held back by the limited availability of the rare earth magnets that make them just so effective.
Re: Google Makani – Wind Energy Kites
#143What happen when I buy one of those, put them in the air and then Google cancel it, will it crash on the ground?
Re: Google Makani – Wind Energy Kites
#144Very similar to underwater kites:
Re: Google Makani – Wind Energy Kites
#145Earlier quoted context omitted.
I've never heard the argument that current wind turbine are unsustainable before. I don't see why that would be so. The base is concrete, the tower is steel, neither of which is exotic. The generator is pretty standard. All of that is industrial tech we invented a century ago, and we know how to maintain it for the long haul. The blades themselves are composite, that may have some longevity issues (you typically need…
My understanding is that, among other things, the generators come under extreme stress during exceptionally windy occasions, causing a lot of wear and tear that happens way up at the top of these giant windmills. These require a lot of manual maintenance, which is dangerous and expensive due to the nature (and location) of the work. Additionally (and as a demonstration of just how much stress they come under), while…
I think last year I read about an experimental setup that uses lidars to measure incoming wind allowing angle to be adjusted, ideally before the gusts hit. No conclusion at that time though.
(The offshore ones are huge and I guess changing the angle can't be done anywhere near fast atm.)
Re: Google Makani – Wind Energy Kites
#146Re: Google Makani – Wind Energy Kites
#147Good, could people just stop messing with how scrolling works.
I have a default zooming of 125% and nobody seems to know how to make the web work for us with disabilities, not even gmail works well. Scrolling pages always look weird for me. Image libraries like lightbox are a special pain in the ass.
Would you willing to provide me any detail about the issues you run into with Gmail?
Re: Google Makani – Wind Energy Kites
#148Would it plummet out of the sky if the wind dropped suddenly?
Stunt kite flyer here. Flying (both powered and unpowered) is about managing the mechanical energy in the kite/aircraft. If you have kinetic or potential energy available, you can always trade one for the other. If you have neither, you've almost landed.
This kite will always be doing quite significant movement, so the "apparent wind" on the airfoil surfaces should keep it moving even when the wind is dying down. Additionally, you can reel in the tether to give a little bit of movement to the kite. Typical kites can be flown by walking backwards at a normal walking speed (4-5 m/s or less).
This looks like a very controllable kite, I'm sure their control programs can land it in pretty adverse conditions safely.
Re: Google Makani – Wind Energy Kites
#149The 60% load factor seems a dream come true... well above offshore wind levels (c. 50%). Having said that, I'm very curious to know the capex per MW, and the ongoing O&M costs for each of the kites. Onshore wind has experienced a considerable decline both in the cost of the turbine and O&M... my impression is that this technology is not going to be cheap to run. Anyone has any insight?
I fly stunt kites and power kites, and what is not immediately apparent to someone who doesn't is that the movement of the kite itself will generate apparent wind (and lift) on the sail/airfoil. Flying in a circle or a figure eight pattern will add a lot of "pull" on the tether. Ie. the load factor of a moving kite is far greater than a stationary kite or propeller.
Here's another kite related technology that uses this to their advantage, they have built a giant computer controlled power kite that is used to power cargo ships (they claim 50% fuel savings in favorable conditions). They're also prototyping for electrical power generation.
Re: Google Makani – Wind Energy Kites
#150The 60% load factor seems a dream come true... well above offshore wind levels (c. 50%). Having said that, I'm very curious to know the capex per MW, and the ongoing O&M costs for each of the kites. Onshore wind has experienced a considerable decline both in the cost of the turbine and O&M... my impression is that this technology is not going to be cheap to run. Anyone has any insight?
What gives you the impression that it won't be cheap to run?
Presumably, if they've got the automation figured out, each unit will just manage itself, launching when wind conditions are favorable.