A paper published on Tuesday by the Nature Conservancy predicts that by 2030, energy production in the United States will occupy a land area larger than Minnesota — in large part owing to the pursuit of domestic clean energy.

The authors call it “energy sprawl” — a term meant to draw attention to habitat destruction, and to warn that biofuels in particular will take up substantial amounts of land.

“There’s a good side and a bad side of renewable production,” said Robert McDonald, a Nature Conservancy scientist and one of the authors, in a telephone interview.

The paper looked at several scenarios, including a “base-case” derived from current Energy Information Agency forecasts for the country’s energy mix in 2030, as well as various permutations of efforts to cap greenhouse gas emissions to combat climate change.

 

The study took into account only land impacts in the United States; thus for example the land required to drill for oil in Saudi Arabia, one of the United States’s biggest suppliers, was not considered. Nor was “indirect land use” taken into account. That is the controversial idea that growing soy for fuel in the United States could simply push soy-for-food production to, say, Indonesia, where CO2-sipping forests would then be razed for soy farming.

Nuclear power is the most compact in terms of the amount of land taken up per unit of energy, according to the study; coal and geothermal energy also took up relatively small amounts of space. Biodiesel made from soybeans, the burning of energy crops to create electricity, and ethanol production had the highest “sprawl” impact.

Asked about the assertion by some solar advocates that covering a 100-mile by 100-mile square of Nevada desert with solar arrays could power the United States, Mr. McDonald said that the study was “trying to avoid that kind of maximal estimate,” and be more realistic about the projected energy mix.

As for climate change, Mr. McDonald said that the Nature Conservancy believes that this is “something humanity absolutely has to deal with,” and the paper highlights several ways to reduce the sprawl. These include reusing already-developed sites, as well as a flexible cap-and-trade system that allows for the development of new nuclear plants and the sequestration of carbon dioxide emissions from coal plants.

But perhaps the most important is energy conservation.

“Saving energy saves land. There’s a real link there.”

Robert McDonald
The Nature Conservancy

這是今天在New York Times 找到的文章 ,文中提到,美國現在為了發展綠能可能付出的代價,像是需要超過一個Minnesota的土地來穫得足夠的乾淨的能源,像是前陣子很夯的生質柴油(biodiesel),其原料就是大豆,用大豆去提煉出乙醇(ethanol)再轉化為汽車可以吃的柴油,但是轉換的比率是相當的低,需要非常大量的大豆去滿足需求,如果美國境內的大豆都被拿來做成生質柴油了,那平常我們吃的大豆要哪來?答案是移到別的地方去耕作,像是印度之類的地方,但是這個動作又可能會需要開拓更多新的耕地而砍伐掉更多的森林,而森林確定減緩溫室效應,吸收二氧化碳的主要機制。

文章最後一句話,But perhaps the most important is energy conservation.,節能可能是最重要的,但是作者可能沒有想清楚如果真的要節能的話全世界的經濟會變成什麼樣子。

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