How much land does it take to power the world?

480,764 views ・ 2021-03-16

TED-Ed


Please double-click on the English subtitles below to play the video.

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No matter how we make electricity, it takes up space.
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Electricity from coal requires mines, and plants to burn it
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and convert the heat into electricity.
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Nuclear power takes uranium mines, facilities to refine the uranium,
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a reactor, and a place to store the spent fuel safely.
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Renewable energy needs wind turbines or solar panels.
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How much space depends on the power source.
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Say you wanted to power a 10-watt light bulb with fossil fuels like coal.
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Fossil fuels can produce up to 2,000 watts per square meter,
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so it would only take a credit card-sized chunk of land to power the light bulb.
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With nuclear power, you might only need an area
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about the size of the palms of your hands.
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With solar power, you’d need at least 0.3 square meters of land—
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twice the size of a cafeteria tray.
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01:01
Wind power would take roughly 7 square meters—
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about half the size of a parking space— to power the bulb.
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When you consider the space needed to power cities, countries,
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and the whole world, it adds up fast.
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Today, the world uses 3 trillion watts of electricity.
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To power the entire world with only fossil fuels,
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you’d need at least about 1,200 square kilometers of space—
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roughly the area of Grand Bahama island.
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With nuclear energy, you’d need almost four times as much space at a minimum—
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roughly 4,000 square kilometers, a little less than the area of Delaware.
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With solar, you’d need at least 95,000 square kilometers,
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approximately the area of South Korea.
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With wind power, you’d need two million— about the area of Mexico.
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For each power source, there’s variability in how much power
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it can generate per square meter,
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but these numbers give us a general sense of the space needed.
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Of course, building energy infrastructure in a desert, a rainforest, a town,
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or even in the ocean are completely different prospects.
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And energy sources monopolize the space they occupy to very different extents.
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Take wind power.
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Wind turbines need to be spread out— sometimes half a kilometer apart—
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so that the turbulence from one turbine
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doesn’t reduce the efficiency of the others.
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So, much of the land needed to generate wind power
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is still available for other uses.
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But the baseline amount of space still matters,
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because cities and other densely populated areas have high electricity demands,
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and space near them is often limited.
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Our current power infrastructure works best
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when electricity is generated where and when it’s needed,
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rather than being stored or sent across long distances.
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Still, space demands are only part of the equation.
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As of 2020, 2/3 of our electricity comes from fossil fuels.
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Every year, electricity generation is responsible for about 27%
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of the more than 50 billion tons of greenhouse gases
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we add to the atmosphere,
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accelerating climate change and all its harms.
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So although fossil fuels require the least space of our existing technologies,
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we can’t continue to rely on them.
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Cost is another consideration.
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Nuclear plants don’t emit greenhouse gases and don’t require much space,
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but they’re way more expensive to build than solar panels or wind turbines,
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and have waste to deal with.
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Renewables have almost no marginal costs—
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unlike with plants powered by fossil fuels,
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you don’t need to keep purchasing fuel to generate electricity.
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But you do need lots of wind and sunlight,
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which are more available in some places than others.
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No single approach will be the best option to power the entire world
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while eliminating harmful greenhouse gas emissions.
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For some places, nuclear power might be the best option
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for replacing fossil fuels.
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Others, like the U.S., have the natural resources
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to get most or all of their electricity from renewables.
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And across the board, we should be working to make our power sources better:
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safer in the case of nuclear,
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and easier to store and transport in the case of renewables.
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