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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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51% Anthropomorphic GHG
By Rudy_Steffen on 2/27/2013 6:43:24 PM , Rating: 2
If you are genuinely concerned about greenhouse gas emissions, I encourage you to adopt a vegan lifestyle. World Watch Institute published a report in 2009 titled "Livestock and Climate Change." Robert Goodland and Jeff Anhang found that 51% of all anthropomorphic GHG emissions is derived by farming animals.

Even if you want to cite the lowest possibility of commodifying animals and how such actions relate to climate change, "Livestocks Long Shadow," an article published by the FAO (2006), estimates that 18% of human derived GHG comes from said industries. That is STILL more emissions than the entire global transportation systems which sits at around 13% of total emissions.

***It is important to note that the FAO study was headed by livestock experts whereas Goodland and Anhang, from the WWI report, are environmental experts.

Here is a further breakdown of statistics related to animal farming. Their conclusion is:

"As the numbers of farm animals reared for meat, egg, and dairy production increase, so do emissions from their production. By 2050, global farm animal production is expected to double from present levels. The environmental impacts of animal agriculture require that governments, international organizations, producers, and consumers focus more attention on the role played by meat, egg, and dairy production. Mitigating and preventing the environmental harms caused by this sector require immediate and substantial changes in regulation, production practices, and consumption patterns."

Keep in mind, this study bases most of its statistics from the lower estimated FAO study.

After skimming through the article for the first time in a year, I see a few outdated statistics. The one that is most pressing is how they cite that 1/3, 33%, of the global land area is used by animal-based industries. The actual number according to the International Livestock Research Institute is 45%.

RE: 51% Anthropomorphic GHG
By roykahn on 2/27/2013 10:03:43 PM , Rating: 2
I better buy more quorn then :)

I don't think there will be any improvement given that people primarily look after themselves before caring for the wider community/country/planet. So if alternative energy or food supply is more expensive, then there's unlikely to be any meaningful change. I recall in Jared Diamond's book Collapse, that a 5% difference in price causes consumers to choose the cheaper option that is environmentally unfriendly.

"So, I think the same thing of the music industry. They can't say that they're losing money, you know what I'm saying. They just probably don't have the same surplus that they had." -- Wu-Tang Clan founder RZA

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