Raise the Hammer
(This blog entry has been updated)
Lucien Gambarota demonstrates how the micro wind turbine can generate electricity (Image Credit: VOA)
The Voice of America reports that a collaboration between engineers at the University of Hong Kong and a renewable energy company has produced a small, lightweight, scalable wind turbine that can generate power even at low wind speeds.
"We never stop this machine and they never stop because there is always one meter per second wind - 365 days, 24 hours a day, they keep working," said [principal inventor Lucien] Gambarota. "They deliver different levels of energy because the wind changes but these turbines they keep moving, they keep spinning."
Gambarota says the small turbines are ideal for crowded cities such as Hong Kong because they can be installed on rooftops and balconies.
Their design is simple: plastic gearwheels, each about 25 centimeters in diameter, are linked to one another and turn, moved by the wind. Groups of gearwheels can be arranged in an array of shapes and sizes, ranging from about two up to thousands of square meters, depending on how much energy is needed and how much space is available. The energy generated by the turbines is stored in a battery, which then powers electrical appliances.
It will be interesting to see how economical these turbines are in application. At $25 for a set of 20 gearwheels 25 cm in diameter, it would cost $20 for a square meter grid of them. Gambarota claims:
Let's say if you have good conditions, five, six meters [of wind] per second, if you are a family with one kid you need most probably three, four square meters of that then you can most probably cover at least 60, 70 percent of your [energy] needs.
At the current price, four square meters would cost $100.
I'd like to see more details on the amount of electricity actually produced by the gearwheels and whether they can be fed back into the electrical grid via an intertie at the power meter.
In any case, it's worth looking at more closely.
Update: okay, so I'm an idiot. When I wrote this, I somehow managed to calculate that it would cost $600 for a square metre of gearwheels. Thanks to commenter "anon" for setting me straight. -Ed.
By seancb (registered) - website | Posted April 03, 2007 at 13:09:51
Tim Hunkin has a very interesting write up on his experience working with wind power: http://timhunkin.com/a125_arch-windpower...
Clearly, he wasn't working on optimizing the energy transfer (which I suspect is a huge part of windpower R&D) but his experimental anecdotes provide a good perspective on what wind can and cannot do. (quote: "David Cameron (the leader of the UK conservative party) got a lot of publicity for fitting a ‘Windsave’ windmill to his chimney (www.windsave.com). Windsave’s website proudly claims their 2m diameter blades will generate 1Kw of electricity at a wind speed of only 12 meters per second. 12 meters per second is force 6 or almost a gale. By the cube law, a moderate breeze of 6 meters a second would only generate 120 watts, certainly not enough for a freezer let alone anything else that might be switched on, and a light breeze of 3 meters a second would only generate 15 watts, enough for one energy saving light bulb.")
In other words, it's good to be skeptical of these wind generators' ouput figures...
By A Robot (anonymous) | Posted April 03, 2007 at 23:09:38
Mr. Cameron gives us other reasons to be skeptical. It seems his precious whirligig had to be taken down.
By anon (anonymous) | Posted April 14, 2007 at 15:15:54
"gearwheels, each about 25 centimeters in diameter" are 16 to the sq metre, so at $25 for a set of 20, a sq metre costs $20.
4 or 5 sq metres for $100?
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