If you thought you’ve seen the last word in wind turbine design, think again.
From a distance it looks like an escaped party balloon in the shape of a donut, but that new thing up in the skies over Limestone, Maine this winter was in fact the 35-foot prototype for a new helium blimp capable of harvesting wind energy at high altitudes, built by the company Altaeros. High-altitude winds are generally stronger and steadier than those near the surface, making them a more efficient feedstock for wind turbines than the low lying winds harvested by conventional wind farms.
How not to harvest wind energy at high altitudes
Building taller wind turbine towers is not a particularly cost effective way to grab high-altitude winds, due to additional expenses for site acquisition (larger towers generally require a larger footprint), manufacturing and transporting the components, constructing the tower, and performing routine inspections as well as maintenance and repair.
The benefits of blimp-lofted wind farms
Altaeros Energies, which calls its new blimp the Airborne Wind Turbine, is one of several companies working around the problem by sailing a turbine into the air (other attempts include hookups between wind turbines and kites).
Along with the benefits of gaining high altitudes without the need for a tower, the dock for the new blimp fits on a trailer for easy portability. The blimp’s tether doubles as a power transmission line and in case of severe weather, the blimp could be grounded by remote control.
Altaeros’s Airborne Wind Turbine
In the test this winter, the Airborne Wind Turbine prototype was lofted 350 feet high, carrying within its donut hole a popular Skystream model turbine from the firm Southwest Windpower. As anticipated, the blimp-mounted turbine generated more than twice the power than it would have if attached to a tower at a more conventional height.
Initially, the company’s goal was to attain a working height of up to 2,000 feet (by comparison, the Empire State Building is 1,250 feet high) and to develop a production model that could be transported in a standard shipping container and installed in just a few days.
So far tests indicate that a height of only 1,000 feet would be sufficient to gain a significant savings over conventional wind power. Within that parameter, Altaeros estimates that the energy produced by its turbine would cost up to 65 percent less than a comparable ground-sited wind turbine.
Very interesting but I’m leery of these tethered designs as they seem very susceptible to accident and sabotage.
But how much steadier would be the winds at 1000 – 2000 ft?
Lower install costs and higher power production is fine but how (much more) reliable are these high altitude winds?
Helium is a bad choice of lifting gas for this application as it refuses to be contained in anything for long because of its monatomicity. It is also expensive and unrenewable, so would need constant replenishment, pushing up costs and increasing downtime.
As people aren’t being carried, hydrogen gas should be acceptable for greater longevity and better lift/volume ratio.
Also, in a land where many people own guns, they should operate far out at sea or above the range of small arms fire to avoid the inevitable antisocial nutters unable to resist the temptation to use them as target practice!
Winds at higher altitudes are much smoother and faster, but at very high altitudes conversion efficiency can tail off with decreasing air density.
Planting a forest of them in the jet stream would be great, but the weight of cables required would make this difficult.
Instead of cables, a blue-sky solution would be to use lasers or masers to transfer the energy to ground stations, also acting as practice for a space-based solar collectors. Beam stabilisation would be challenging, but not much different from video stabilisers already in use by UAVs.
They could also be used to extract and compress CO2 (and water vapour) from the atmosphere directly, or support sun shades to reduce local insolation.
How about using a few of them to make a high altitude aircraft carrier or spaceport?
Best not tether them over Texas.
Other than the turbine, these have been around for 70 years. They’re called barrage balloons. They deal Death to aircraft that run into the tethers.
Also Death to whatever they fall on, when they fall.
At least when ground-based turbines burn up and fall down, you have a pretty good idea where they’ll come down. Put one of these suckers at the end of a 2000 foot tether, and the kill zone over which it can fall is something like 150 acres.
ahaveland, “use lasers or masers to transfer the energy to ground stations?” There are a few problems with that:
1. without the tether, the equipment will fly away.
2. without the tether, the turbine won’t spin.
3. a laser or maser of sufficient power would be a Death Ray.
Just what I want above MY neighborhood: a precision-aimed death ray strategically perched at 1500 foot altitude.
1. I did not suggest no tether, that would be silly. A kevlar tether is much lighter than one containing a large amount of copper, so the balloon could reach a higher altitude or support more mass.
2. See 1.
3. It’s a bonus feature… 🙂 but seriously, no way would these be residential installations. The beam could be divergent and collected over a larger area reducing the precision required for tracking a dangerous energy dense beam.
(It could have an application to defend forward bases in hostile territory as well as reduce fuel supply-line dependency. It floats whether the wind blows or not, and power supply can be bidirectional.)
“Just what I want above MY neighborhood: a precision-aimed death ray strategically perched at 1500 foot altitude.”
NIMBY syndrome right there.