but that doesn't have to be the case in the future.

但未來不一定如此。

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。

So, what are the differences between these options?

那麼這些方案有什麼不同？

And which one's best?

哪一個最好呢？

Gasoline is refined from crude oil,

汽油是由原油提煉而成，

a fossil fuel extracted from deep underground.

一種從地下深處提取的化石燃料。

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。

There are hundreds of different hydrocarbons in crude oil,

原油中有數百種不同的碳氫化合物，

and different ones are used to make gasoline and diesel,

分別用於製造汽油和機油，

which is why you can't use them interchangeably.

因此它們才不能互換使用。

Fuels derived from crude oil are extremely energy dense,

從原油中提取的燃料能量密度極高，

bringing a lot of bang for your buck.

非常具有經濟效益。

Unfortunately, they have many drawbacks.

可惜它們也有很多缺點。

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。

Air pollution from burning fossil fuels like these

這些燃燒化石燃料帶來的空氣汙染，

kills 4.5 million people each year.

每年導致 450 萬人死亡。

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%，

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。

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。

In the U.S. alone, storms caused by climate change

僅在美國，由氣候變化引起的風暴

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。

So, while gas is efficient,

所以，雖然天然氣效率高，

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。

The most common alternative is electricity.

最常見的替代品是電力。

Electric cars use a battery pack and electric motor

電動汽車使用電池組和電動機

instead of the internal combustion engine found in gas-powered cars,

而非汽油動力汽車中的內燃機，

and must be charged at charging stations.

並且必須在充電站充電。

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。

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，

they can avoid greenhouse gas emissions entirely.

就可以完全避免溫室氣體排放。

They're more expensive than gas-powered cars,

它們比汽油驅動的汽車更貴，

but the cost difference has been shrinking rapidly since 2010.

但自 2010 年以來，成本差異迅速縮小。

The other alternatives to gasoline are other liquid fuels.

汽油的其他替代品是其他液體燃料。

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。

and used in the same cars.

並用在同一種車款上。

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，

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，

and don't add to overall emissions.

這樣不會增加整體排放量。

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，

and combine its carbon with the hydrogen in water.

並將碳與水中的氫結合。

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，

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。

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，

an obstacle to using them in cars.

造成汽車使用的障礙。

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，

which sequester carbon from the air through photosynthesis.

透過光合作用從空氣中吸收碳。

But growing the plants also has to be carbon neutral,

但種植的也要是碳中和的植物，

which rules out many crops that require fertilizer,

這就排除了許多需要化肥的農作物，

a big contributor to greenhouse gas emissions.

是溫室氣體排放的主要來源。

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

or plants that don't require fertilizer to grow.

或不需要施肥就能生長的植物製造。

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。

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。

Unfortunately, the high upfront costs of implementing new technologies

可惜實施新技術的前期成本很高，

and heavy subsidies for the producers of fossil fuels

而對化石燃料生產者的大量補貼

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。

This cost difference is known as a green premium.

這種成本差異叫做綠色溢價。

Governments have already started subsidizing electric vehicles

政府已經開始補貼電動車

to help make up the difference.

以彌補差額。

In some places, depending on the costs of electricity and gas,

在一些地方，取決於電、氣的成本，

electric cars can already be cheaper overall,

電動汽車的整體價格已經更便宜了，

despite the higher cost of the car.

儘管汽車的成本較高。

The other alternatives are trickier, for now.

就目前而言，其他的替代選擇更為棘手。

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。

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，

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

and sustainable for our planet.

且可以為地球永續使用的燃料。