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Historically, most cars have run on gasoline,
歷史上大多數汽車皆仰賴汽油運行,
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but that doesn't have to be the case in the future.
但未來不一定如此。
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Other liquid fuels and electricity can also power cars.
其他液體燃料和電力也可以為汽車提供動力。
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So, what are the differences between these options?
那麼這些方案有什麼不同?
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And which one's best?
哪一個最好呢?
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Gasoline is refined from crude oil,
汽油是由原油提煉而成,
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a fossil fuel extracted from deep underground.
一種從地下深處提取的化石燃料。
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The energy in gasoline comes from a class of molecules called hydrocarbons.
汽油中的能量來自一種叫做碳氫化合物的分子。
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There are hundreds of different hydrocarbons in crude oil,
原油中有數百種不同的碳氫化合物,
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and different ones are used to make gasoline and diesel,
分別用於製造汽油和機油,
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which is why you can't use them interchangeably.
因此它們才不能互換使用。
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Fuels derived from crude oil are extremely energy dense,
從原油中提取的燃料能量密度極高,
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bringing a lot of bang for your buck.
非常具有經濟效益。
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Unfortunately, they have many drawbacks.
可惜它們也有很多缺點。
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Oil spills cause environmental damage and cost billions of dollars to clean up.
溢油破壞環境,清理費用高達數十億美元。
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Air pollution from burning fossil fuels like these
這些燃燒化石燃料帶來的空氣汙染,
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kills 4.5 million people each year.
每年導致 450 萬人死亡。
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And transportation accounts for 16% of global greenhouse gas emissions,
運輸業佔全球溫室氣體排放量的16%,
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almost half of which comes from passenger cars burning fossil fuels.
其中近一半來自燃燒化石燃料的客車。
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These emissions warm the planet and make weather more extreme.
這些排放造成地球暖化,使天氣更加極端。
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In the U.S. alone, storms caused by climate change
僅在美國,由氣候變化引起的風暴
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caused $500 billion of damage in the last five years.
在過去5年就造成了 5000 億美元的損失。
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So, while gas is efficient,
所以,雖然天然氣效率高,
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something so destructive can't be the best fuel.
這麼具破壞性的東西不可能是最好的燃料。
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The most common alternative is electricity.
最常見的替代品是電力。
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Electric cars use a battery pack and electric motor
電動汽車使用電池組和電動機
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instead of the internal combustion engine found in gas-powered cars,
而非汽油動力汽車中的內燃機,
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and must be charged at charging stations.
並且必須在充電站充電。
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With the right power infrastructure, they can be as efficient as gas-powered cars.
如果有合適的電力基礎設施,它們可以像汽油動力汽車一樣高效。
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If powered by electricity generated without fossil fuels,
如果由不使用化石燃料產生的電力驅動,
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they can avoid greenhouse gas emissions entirely.
就可以完全避免溫室氣體排放。
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They're more expensive than gas-powered cars,
它們比汽油驅動的汽車更貴,
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but the cost difference has been shrinking rapidly since 2010.
但自 2010 年以來,成本差異迅速縮小。
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The other alternatives to gasoline are other liquid fuels.
汽油的其他替代品是其他液體燃料。
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Many of these can be shipped and stored using the same infrastructure as gasoline,
其中許多可以使用與汽油相同的基礎設施進行運輸和儲存。
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and used in the same cars.
並用在同一種車款上。
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They can also be carbon-neutral if they're made using carbon dioxide from the atmosphere,
如果是用二氧化碳製造,它們也可以達到碳中和,
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meaning when we burn them, we release that same carbon dioxide back into the air,
表示燃燒它時,同樣的二氧化碳會釋放回空氣中,
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and don't add to overall emissions.
這樣不會增加整體排放量。
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One approach to carbon-neutral fuel is to capture carbon dioxide from the atmosphere
製作碳中和燃料的一種方法是從大氣中捕獲二氧化碳,
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and combine its carbon with the hydrogen in water.
並將碳與水中的氫結合。
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This creates hydrocarbons, the source of energy in fossil fuels,
這就產生了碳氫化合物,也就是化石燃料的能源來源,
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but without any emissions if the fuels are made using clean electricity.
而且如果使用清潔電力製造燃料,則不會有任何排放。
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These fuels take up more space than an energetically equivalent amount of gasoline,
這些燃料比等量的汽油占用更多的空間,
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an obstacle to using them in cars.
造成汽車使用的障礙。
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Another approach is to make carbon-neutral fuels from plants,
另一種方法是用植物製造碳中性燃料,
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which sequester carbon from the air through photosynthesis.
透過光合作用從空氣中吸收碳。
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But growing the plants also has to be carbon neutral,
但種植的也要是碳中和的植物,
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which rules out many crops that require fertilizer,
這就排除了許多需要化肥的農作物,
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a big contributor to greenhouse gas emissions.
是溫室氣體排放的主要來源。
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So, the next generation of these fuels must be made from either plant waste
所以,新一代燃料必須用植物廢料
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or plants that don't require fertilizer to grow.
或不需要施肥就能生長的植物製造。
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Biofuels can be about as efficient as gasoline, though not all are.
生物燃料的效率可以和汽油差不多,但不是所有生物燃料都是如此。
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For a fuel to be the best option, people have to be able to afford it.
要成為最好的燃料選擇,前提是必須讓人們負擔得起。
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Unfortunately, the high upfront costs of implementing new technologies
可惜實施新技術的前期成本很高,
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and heavy subsidies for the producers of fossil fuels
而對化石燃料生產者的大量補貼
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mean that almost every green technology is more expensive than its fossil-fuel-based cousin.
代表幾乎所有的懷寶技術都比以化石燃料為基礎的技術更昂貴。
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This cost difference is known as a green premium.
這種成本差異叫做綠色溢價。
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Governments have already started subsidizing electric vehicles
政府已經開始補貼電動車
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to help make up the difference.
以彌補差額。
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In some places, depending on the costs of electricity and gas,
在一些地方,取決於電、氣的成本,
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electric cars can already be cheaper overall,
電動汽車的整體價格已經更便宜了,
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despite the higher cost of the car.
儘管汽車的成本較高。
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The other alternatives are trickier, for now.
就目前而言,其他的替代選擇更為棘手。
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Zero-carbon liquid fuels can be double the price of gasoline or more.
零碳液體燃料的價格可能是汽油的兩倍或以上。
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Innovators are doing everything they can to bring green premiums down,
創新者正竭盡全力降低綠色溢價,
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because in the end, the best fuel will be both affordable for consumers
畢竟,最好的燃料是消費者負擔得起的
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and sustainable for our planet.
且可以為地球永續使用的燃料。