There's recently been a lot of bad news about climate change.
But we must not despair; solutions to our problems unquestionably exist. The sun provides us daily with enormous amounts of energy. Harnessing 1% of 1% of that energy (either directly, or by harnessing the winds or waves it powers), would power all of civilization.
This diary is nominally about a solution (Flying Electric Generators, or FEGs) which have the potential to supply clean, renewable electricity to the entire world. But I write it to provide an example of how the ideals of the enlightenment-- curiosity, rational approach to problem-solving, pragmatism, enlightened debate—may help solve our problems.
Briefly, most of the wind is in the sky, so why not build the wind farms up there? Flying robotic wind turbines will use a small part of the power the generate to stay aloft by running their horizontal turbines like helicopter blades, and send the rest down through their tethers.
High level winds are highly reliable, and harvesting 1% of the Jet Stream's power could supply us with all the power we use now.
The best part? Flying windfarms could be reality within five years, producing power more cheaply than coal.
Aerial vs Terestial Wind Farms
Overall, wind is one of the cleanest and cheapest sources of power. Denmark generates 20% of its electricity from wind. Wind scales well, and the technology is well understood: there are several large companies churning out turbine after turbine. Of course, Jeromehas written eloquently about the advantages of wind far better than I can.
Currently, wind power is earth-bound. The tallest towers are a little over 200m tall. That's unfortunate, since the wind is stronger a few miles up-- a lot stronger. Atmospheric scientist Ken Caldeira has estimated that capturing 1% of the jet stream's energy could power all of civilization.
And while the jet stream moves around, high-level winds above the continental US (or similar latitudes) are very likely to be blowing strongly (which is why it westward cross-country flights usually take longer than eastward). A generator able to tap these winds could generate power 80% of the time, instead of 30% for terrestrial towers.
Wind turbines have a reputation for killing birds (even though cats kill 10000 times as many) and for spoiling views. I find both of these objections rather silly, but I'll note that neither concern applies to a wind turbine happened to be located a few miles overhead.
But how, exactly, does one site a wind turbine 5 miles high?
Flying robotic wind turbines
Enter Dave Shepard. He began his career cracking Japanese military codes in World War II and went on to develop machines for reading characters. His work led to the squared-off numbers found on many credit cards.
Mr. Shepard has founded Sky Wind Power, which (working with working with Australian Engineering Professor Bryan Roberts) aims to produce commercially viable Flying Electric Generators.
The flying generator is basically a cross between a kite and a helicopter. It has four rotors, each of which is turned by the wind and generates power the same way as a terrestrial wind turbine. They also act like the surface of a kite, keeping the whole contraption aloft. When the wind is strong enough (most of the time), power is sent down to earth through the tether. When it weakens, power can be sent up to the FEG to power the rotors, causing the whole craft to levitate like a helicopter.
Mr. Shephard chose to use four rotors to overcome one of the most difficult problems inherent in building such a device-- avoiding maintenance. Most helicopters and planes have to be serviced after only a few days of use, while a FEG would likely have to work for months at a time.
Helicopters must be serviced so frequently because they must change the pitch of their blades fast and frequently-- often with every rotation. That causes stress to build up and parts to wear out fast. But with four blades, as with Mr. Shepard's design, one can get the same effect by changing the tilt of one or two whole rotors. (It also doesn't hurt that the FEG will mostly be staying in one place, not executing complicated maneuvers.)
Mr. Shepard estimates that he will be able to produce power for 2 cents / kilowatt-hour, which is cheaper than coal. And its coming soon: Professor Roberts "demonstrated a FEG in Australia at an altitude of sixty feet over a decade ago... We expect to make a demonstration in the U.S. less than three years from now at high altitude in normal high altitude winds. In four years I would expect this sort of technology to be in active use."
And eventually, the use will be large-scale:
Forty-three such FEG "arrays" -- each comprising 600 FEGs -- would, he estimates, generate sufficient electricity to power the whole of the U.S.
"Our calculations show that by reserving less than one four-hundredth of U.S. air space, located at relatively remote locations not on airway routes, all of America's electrical energy needs could be met," he says.
"That is considerably less airspace than is already restricted for other purposes, primarily military."
Paging Dr. Franklin
Q. What happens if you fly a gigantic metal kite with a multi-mile long string in the middle of a thunderstorm?
A. Hopefully, we'll never find out. FEGs won't fly during thunderstorms. It turns out that lightning strikes are surprisingly rare. As this map shows, most of the US (except for the southeast) gets 4 or fewer lightning bolts per square kilometer per year. The northeast and west gets just 1 per square kilometer per year.
And if flying helicopters don't work?
If flying helicopters should prove too complicated and difficult to maintain, there are other ways to harvest the energy up high-level winds. A Candian company called Magenn Power has proposed using helium to raise turbines to 1 kilometer.
One way or another, FEGs are coming.
Comparing FEGs to coal
Coal has two huge advantages: it is cheap (if you ignore the externalities) and it is (allegedly) always-on.
If Mr. Shepard's calculations are correct, FEGs will be cheaper than coal. I am not aware of any obvious externalities. It is true that taking energy from the winds will slow them slightly, but the effect on weather is likely to be a lot smaller than the changes that fossil fuel (including coal) emissions cause to weather patterns.
Contrary to myth, coal plants are not always on. Actually, they are "on" about 93% of the time. The rest of the time, they are down for scheduled or unscheduled maintenance. FEGs should have an uptime of about 80%. This means that if you have two widely separated FEGs, at least one should be on about 96% of the time.
Comparing FEGs to nuclear energy
[chapter1 dons flame suit]
Both of the previous comments also apply. Furthermore, nuclear is often said to be the only non-fossil fule power source capable powering civilization.
Hogwash. As noted above, FEGs can supply all the electricity we need several times over.
Furthermore, why would anyone spend a couple of billion on a nuclear plant-- that will take a decade or more to build-- when FEGs could be producing cheaper power in five years?
What are we waiting for?
In any event, I hope this makes one thing clear. Yes, our energy and environmental problems are extremely serious. Yes, our current rulers are insane. But don't underestimate humanity. We may yet devise ways to power our civilization which have few, if any, negative side effects.
Some say we're hopelessly dependent on fossil fuels, and they're growing scarcity will destroy our civilization.
Hogwash, I say. With enough cleverness, resources (from the market or government) and luck, a world of electric cars and clean, cheap, renewable power could become reality before Bush's successor finishes his first term.
When FEGs fly.