The best place for a wind turbine: 30,000 feet above ground
in generating that power and its impact upon the atmosphere.
Tethers for airborne wind generation assets do not require a lot of ground space, nor are they labor intensive. They do not pollute.
“They could stay up a year, then come down for a maintenance check and then go back up,” Moore said. “Or they could be reeled in case of a storm. Or one operator could watch over 100 of these.”
Wind power is nothing new. Wind turbine farms have dotted the landscape for more than a generation. So why is this different? “At 2,000 feet (610 meters), there is two to three times the wind velocity compared to ground level,” Moore said. “The power goes up with the cube of that wind velocity, so it’s eight to 27 times the power production just by getting 2,000 feet (610 m) up, and the wind velocity is more consistent.”
Send turbines farther aloft, into the 150 mph (240 kph) jet stream at 30,000 feet (9,150 m), and “instead of 500 watts per meter (for ground-based wind turbines), you’re talking about 20,000, 40,000 watts per square meter,” Moore said. “That’s very high energy density and potentially lower cost wind energy because of the 50-plus fold increase in energy density.”
So why is it not being done? Or at least, why is it not being researched more expansively?
One answer involves the vehicle to be flown. Another involves where to fly it. “All you have right now are small companies doing the research, and all you can expect of them is to focus on one little piece,” Moore said. “They have enough trouble just analyzing their concept without worrying about geography, about ‘where should I mount these so that the wind is optimal?’ ”
The ultimate answer could be the federal government itself.
“In my mind, it’s crazy that there isn’t federal investment in this area, because the questions are just too great for small companies to answer,” Moore said.
It is one of the reasons he has undertaken the wind-power study, which actually, he maintains, should be two studies. One involves the technology and geography. The other involves the interaction between those elements and other competitors for airspace.
That means dealing with current Federal Aviation Administration regulations and with those that might be necessary to accommodate an airspace that includes manned aircraft, the unmanned aircraft in the future, plus wind-borne energy turbines.
First things first, though. “It’s important to understand the concept without regulatory constraints because it lets decision-makers and investors understand the topology of the solution space,” Moore said. “We don’t want to just look at the problem with regulatory blinders on, but we don’t just look at it with no blinders on, either. We have to look at it both ways.”
He offers another option that can help the FAA in its decision-making. “Offshore deployment of these airborne systems probably makes the most sense in terms of both airspace and land use, because there is little to no demand for low altitude flight over oceans 12 miles (19 to 20 km) offshore,” Moore said.
“Also, unlike ground-based turbines, there is almost no additional cost for airborne systems offshore because huge platforms are not required to support the structure or resist large tower bending moments.
“NASA Wallops could have an important role as an airborne wind testing center with access to offshore wind profiles in controlled airspace.”
What all this has to do with NASA goes beyond the agency’s commitment to help the nation with clean energy solutions. It also involves some of the core capabilities of the agency in aeronautics, composite materials and air space management.
“We’ve shown in the past that NASA’s expertise can help broker and bring an understanding to the FAA as to how these technologies can map into constructive purposes,” said Moore, who has met with wind power energy industry leaders, as well as officials from the National Renewable Energy Laboratory and Department of Energy in undergoing this project.
“They welcome this study because they’ve never dealt with flying systems and NASA has,” Moore said. “You can’t come up with advanced concepts until you understand the requirements well, and frankly, I don’t think anybody understands the requirements well.”
It is why he is undertaking the project: to bring a sense of what is going to be necessary to harvest power from the wind.
