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But there are limits that could hold wind back from growing

A new study from Harvard University's School of Engineering and Applied Sciences says that the generating capacity of large-scale wind farms isn't quite as high as scientists previously thought.

The study was led by Harvard applied physicist David Keith, who showed that we may not have access to as much wind power as once thought. Keith is an internationally renowned expert on climate science.

According to Keith's study, individual wind turbines each create a "wind shadow," which is where air is slowed by the drag on the turbine's blades. Wind farms with as many turbines packed into an area as possible but with just the right amount of spacing in between them are optimal for decreasing this drag.

However, the larger these wind farms are, the more they communicate and regional-scale wind patterns are even more important. Keith said previous generating capacity of large-scale wind farms ignored the drags and these wind patterns.

Keith's study said that the generating capacity of large-scale wind farms that are larger than 100 square kilometers could peak anywhere from 0.5 and 1 watts per square meter. Prior estimates put these figures at 2 to 7 watts per square meter.


“If wind power’s going to make a contribution to global energy requirements that’s serious, 10 or 20 percent or more, then it really has to contribute on the scale of terawatts in the next half-century or less,” said Keith.

But there are limits that could hold wind back from growing. Keith said that if wind were to exceed 100 terawatts, it would have a huge impact on global winds and eventually climate -- which could negatively affect climate more than doubling CO2.

“Our findings don't mean that we shouldn’t pursue wind power—wind is much better for the environment than conventional coal—but these geophysical limits may be meaningful if we really want to scale wind power up to supply a third, let’s say, of our primary energy,” said Keith. 

“It’s clear the theoretical upper limit to wind power is huge, if you don't care about the impacts of covering the whole world with wind turbines. What’s not clear—and this is a topic for future research—is what the practical limit to wind power would be if you consider all of the real-world constraints. You'd have to assume that wind turbines need to be located relatively close to where people actually live and where there's a fairly constant wind supply, and that they have to deal with environmental constraints. You can’t just put them everywhere.”

Keith concluded that we'll need to find sources for tens of terawatts of carbon-free power "within a human lifetime" in order to stabilize the Earth's climate.

“It’s worth asking about the scalability of each potential energy source—whether it can supply, say, 3 terawatts, which would be 10 percent of our global energy need, or whether it’s more like 0.3 terawatts and 1 percent," said Keith.

Source: Harvard University



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RE: Yet another reason to switch to nuclear
By FITCamaro on 2/27/2013 11:24:48 AM , Rating: 2
Modern plants don't have to worry about the problems that occurred on 3 Mile Island. That accident did not cause any health problems either. It was a partial meltdown, not a full one. Even if it did, are we going to live in fear of what might happen from something over 30 years ago?

Modern nuclear designs and thorium reactors don't have the waste problem. Reprocessing may result in weapons grade material, but I think if the French can handle it, we can.

Wind and solar will never be able to be our only source of power no matter how good it is. It's too variable, requires vast tracks of land (which upsets the environmentalists just as much as nuclear), and still requires back up plants to be on standby when they're not generating enough. Why double build?


RE: Yet another reason to switch to nuclear
By GotThumbs on 2/27/2013 11:43:28 AM , Rating: 2
I agree with your comment.

I don't feel there is a single solution for our/the worlds needs, but each solution should be considered based on the region and populous needs.

In time, scientists may very well develop new solutions that are cleaner and have fewer waste/pollutants.

We just need to keep open minds to meeting today's needs and tomorrows as well.

Anything is possible if we work together and don't wear blinders to current and future solutions.

Just wish we could get the president and congress to actually try to work together. Of course He would need to stop his campaigning. Does someone need to tell him hes in for another four years and can now start doing the job? Sorry, had to at least get a dig in. It's not all one persons fault, but leadership is grossly absent in Washington IMO.

Best wishes for all,


By FITCamaro on 2/28/2013 7:50:50 AM , Rating: 2
I agree. I don't think homeowners using solar to offset energy needs are a bad idea at all if their geographic location makes sense for it. But I do not agree with taxpayers helping to pay for those installations.

Wind is just a dumb idea all around given the cost, variability, and land required.

Yes it's not one person or parties fault for gridlock in Washington, but the President going around saying the other side pretty much wants to kill people doesn't help.


By johnsmith9875 on 3/4/2013 1:38:35 AM , Rating: 2
TMI was a full meltdown. To this very day journalists report that it was a partial meltdown. It took years before they could peer into the reactor core and when they did they were surprised to find the core gone, and a puddle of melted nuclear material at the bottom of the containment vessel.
Harrisburg, PA was also blanketed with a huge radioactive steam release.
They were getting ready to evacuate the entire city at one point, but I can't imagine that would have worked because the idea of hundreds of thousands of people fleeting at the same time, that would take days or even weeks, too slow for a reactor accident.


By johnsmith9875 on 3/4/2013 1:47:32 AM , Rating: 2
True, solar power is unreliable, the sun only comes out every day.


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