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As much as I believe in the future of renewable energy, currently alternative sources of energy only account for maybe 3% of the nation's energy use, with the bulk still coming from fossil fuels. Critics will often say that the technology simply isn't there, but that's what I love about technology: it doesn't stay the same. In the case of renewable energy, not only has improving technology led to lower price and increased effectiveness, it has also led to the development of new ways of tapping renewable energy.
Take wind power, already the fastest growing sector of renewable energy. But despite its
vast potential, wind power, like other forms of renewable energy, is very dependent on daily weather conditions. In other words, if the wind isn't blowing, or the sun isn't shining, then wind turbines and solar panels are fairly useless.
The Sky Windpower Corporation thinks they have an answer to this problem, with a new invention they're calling a "Flying Windmill". The idea is to use Flying Electric Generator (FEG) technology to take advantage of the much stronger winds available at higher altitudes. This would involve a "helicopter-like rotorcraft" to put wind turbines in the sky, and then to feed the generated electricity to the ground via a cable. The benefits to this approach versus traditional ground based wind power are numerous:
At 15,000 feet, winds are strong and constant. On the ground, wind is often unreliable -- the biggest problem for ground-based wind turbines. "For FEGs, the winds are much more persistent than on ground-based machines," said Roberts. "That's part of the benefit, more power and greater concentration."
Ken Caldeira, a climate scientist at Lawrence Livermore National Laboratory, said tapping into just 1 percent of the energy produced by high-altitude winds could satisfy a lot of the world's power needs.
"It's absurd that all this time we have turned a blind eye to the energy right above our heads," he said. "High-altitude wind power represents the most concentrated flux of renewable energy found on Earth."
At certain locations, the efficiency of a flying generator can be as high as 90 percent, three times higher than its grounded counterpart, according to Sky WindPower.
At this efficiency, FEGs could become the nation's cheapest source of electricity, with an estimated cost per kilowatt hour of less than 2 cents, about half the price of coal, according to the Power Marketing Association.
So clearly FEGs have great potential to solve many of our energy needs in the future. But if you're like me, you'll be wondering about the maintenance issues involved with keeping the FEGs in the sky for months at a time. My first thought on imagining a flying craft attached to the ground via a cable was that the idea could never work, that costs associated with maintenance and accidents would make it impossible to cheaply obtain the wind energy.
But I'm not an engineer, and Bryan Roberts, the inventor behind the FEGs, swears that the project meets FAA standards and is entirely practical. Such a new concept may seem strange at first, but really is not that different from satellites in the sky, or flying planes. Take a look at the artist rendering of the skymill concept.
Another recent development in renewable energy has been in what are known as solar towers, designed by Australia-based EnviroMission Limited. A solar tower consists of a 3,280-foot chimney, and a 25,000-acre, transparent circular skirt at the base that acts like a greenhouse. Basically, a solar tower is built around a simple concept: heat rises. The greenhouse at the base causes the air inside to be heated by the sun, and the heated air is then funneled through the chimney. This air pushes 32 wind turbines inside the chimney, creating electricity like a conventional wind farm.
The solar tower's size is impressive enough, as it will be the tallest man made structure in the world. More importantly, a solar tower can produce up to 200 megawatts of energy, or enough to power 200,000 homes, according to the company press release. What's more, it has a distinct advantage over conventional renewable technologies, according to this article in Wired:
But the Solar Tower has a major advantage over wind farms and solar generators: It can operate with no wind, and 24 hours a day. Thanks to banks of solar cells, the tower stores heat during the day, allowing it to produce electricity continuously.
Both the FEG technology and the solar tower represent technological breakthroughs, as they both address a fundamental problem with conventional methods of generating renewable energy: the inability to produce energy on a consistent basis. These new methods, unlike their predecessors, promise electrical generation 24/7, which is crucial to building a renewable energy infrastructure that can replace the current fossil fuel based system.
Which is not to say that both the flying windmill and the solar tower will be staples of our future energy system. It's a little too early for either of these technologies to say that they will be commercially viable, or capable of living up to their promise. Right now, I would bet more on the solar tower, simply because EnviroMission has already landed a contract to build a solar tower in Australia, and there are also plans to build one in my own home state of Texas. Meanwhile, Sky WindPower is still in the process of raising capital to build the first full-size flying generators.
However it plays out, I think the important thing to remember is that renewable energy is still a relatively new field, and that technological changes will continue to affect how we obtain energy in the future. So maybe rising prices for fossil fuels won't cause economic turmoil; perhaps we will instead see bold new ways of providing renewable energy.