By John Herrman
Posting in Cities
A proposed installation outside of Abu Dhabi would harness the power of more than a thousand blade-less, waving stalks.
Ask anyone to describe a wind farm, and they'll tell you about a field of windmills, with massive blades that chop the air in unison, sending their kinetic energy to simple electric generators. Ask New York design firm Atelier, and they'll give you a field of grass. A field of 180-foot, piezoelectric, carbon fiber grass.
The concept (via Discovery News) is called Windstalk, and came about in response to a call for ideas for the city of Masdar, a planned development outside of Abu Dhabi. The call took the form of a contest, called the Land Art Generator Initiative, which asked for "public art installations that have the added benefit of large scale clean energy generation." Insofar as the Windstalk would be completely and utterly surreal to witness in all its heaving glory, it succeeded; Masdar awarded it second place.
So yes, it's cool. But how on Earth does (or would) it work? Atelier describes the wind farm like this:
Our project consists of 1203 stalks, 55 meters high, anchored on the ground with concrete bases that range between 10 to 20 meters in diameter. The stalks are made of carbon fiber reinforced resin poles, 30 cm in diameter at the base and 5 cm at the top. The top 50 cm of the poles are lit up by an LED lamp that glows and dims depending on how much the poles are swaying in the wind. When there is no wind–when the poles are still–the lights go dark.
Sounds pretty! But again, how? Ah ha!:
Within each hollow pole is a stack of piezoelectric ceramic discs. Between the ceramic disks are electrodes. Every other electrode is connected to each other by a cable that reaches from top to bottom of each pole. One cable connects the even electrodes, and another cable connects the odd ones. When the wind sways the poles, the stack of piezoelectric disks is forced into compression, thus generating a current through the electrodes. Within each concrete base is a hollow chamber that houses a torque generator.
Where a typical windmill converts wind energy into rotation, which powers a spinning generator that creates electricity, Windstalks convert winds energy into electricity by harnessing the strain and flex of its stalks. In theory, the farm should be able to produce about as much electricity with the utilized land as a traditional wind farm would, all the while looming, eel-like, over its neighboring metropolis.
One problem! Piezoelectrics, promising as they may be, have never been used on this scale. In fact, DARPA is struggling to harness the energy from the bottoms of soldiers' boots. Successful deployments of piezoelectric generators have been relative modest, like this generative turnstile at a Japanese train station. A jump to a large windfarm based entirely on piezoelectric carbon fiber tubes would require a long sequence of advances in design and large-scale fabrication, and would likely be prohibitively expensive, at least for the foreseeable future.
Regardless, it's good to see some fresh ideas in the wind power arena. Masdar's Windstalk installation may never come to pass, but don't be too surprised if a much more modest version crops up elsewhere.
Oct 15, 2010
I wonder how well these would work underwater. Seems like a decent way to generate hydro-electric power without too much disruption to the wildlife or currents around them.
Back in the 1990s it was proposed to mount small piezoelectric ribbons in highway guardrails to generate power from the wind created by passing vehicles. The project went nowhere because the power generated was not enough to recharge batteries in roadside signs. Solar panels were found to be a much more cost effective and reliable option and are now ubiquitous on many highways. I wonder how the projected cost to build and operate this type of wind farm compares to conventional power generation?
It's an interesting concept. If the technology can be mass-produced and production cost's lowered, it could be put into buildings, bridges, road-beds, train tracks, shock-absorbers, you name it. If it moves, it can generate electricity. Of course, hooking up cows, horses, fish and people to the smart grid may present some challenges.
There are a lot of innocuous places these stalks could be placed without interfering with people's sensibilities. They could even be used (with modification) between highways and homes to help screen the noise. Sound absorbing coatings would help reduce noise but not reduce the efficiency.
Make this thing about 60 feet tall, and I will install one in each corner of my backyard near the trees. This is a great potential answer to residential wind as the neighbors would have nothing to complain about - as long as you lose the 'lights'.