Can 100% renewable energy power the world

能100%靠可再生能源供給全世界嘛

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Every year, the world uses 35?billion barrels of oil.

This massive scale of fossil fuel ?dependence pollutes the Earth

and it won't last forever.

Scientists estimate that we've consumed about 40% of the world's oil.

According to present estimates,

at this rate, we'll run out of oil and gas in 50?years or so,

and in about a century for coal.

每年，全世界會用掉 350?億桶油。

這種對化石燃料的大規(guī)模依賴 會污染我們的地球，

而且不會永遠(yuǎn)持續(xù)下去。

科學(xué)家估計我們已經(jīng)使用了大約世界總油量的百分之四十。

根據(jù)目前的估計，

以這個速度進行下去，我們將在大約 50?年后用光總有的油和氣，

在一個世紀(jì)后用盡所有的煤炭。

On the flip side, we have abundant sun, water, and wind.

These are renewable energy sources,

meaning that we won't use them up over time.

What if we could exchange ?our fossil fuel dependence

for an existence based ?solely on renewables?

另一方面，我們擁有 充足的陽光、水和風(fēng)。

這些是可再生能源，

意思是無論多久， 我們都不會用盡這些資源。

如果我們可以把對化石燃料的依賴

換成僅靠可再生能源 的存在方式會是什么樣呢？

We've pondered that question for decades,

and yet, renewable energy still only provides about 30% of our needs.

That's because reaching 100% requires renewable energy that's inexpensive

and accessible.

This represents a huge challenge,

even if we ignore the politics involved and focus on the science and engineering.

幾十年來，我們一直在思考那個問題，

然而，可再生能源仍只能滿足 我們對能源需求的大約百分之十三。

那是因為，要達到百分之百的利用率， 可再生能源需要更廉價，

而且要容易得到。

這是項強大的挑戰(zhàn)，

即使我們忽略政治的參與，集中在科學(xué)和工程上面。

We can better understand the problem by understanding how we use energy.

Global energy use is a diverse ?and complex system,

and the different elements ?require their own solutions.

But for now, we'll focus on two of the most familiar in everyday life:

electricity and liquid fuels.

Electricity powers blast furnaces, ?elevators, computers,

and all manner of things in homes, businesses, and manufacturing.

Meanwhile, liquid fuels ?play a crucial role

in almost all forms of transportation.

我們可以通過我們?nèi)绾?使用能源來理解這個問題。

全球能源使用是 一個多樣而且復(fù)雜的系統(tǒng)，

并且不同的元素需要 個性化的解決方式。

但是現(xiàn)在，我們將集中于每日生活中最熟悉的兩項：

電能和液體燃料。

電能為高爐、電梯、電腦，

還有所有家里、企業(yè)和制造業(yè)需要 的各個方面提供能量。

同時，液體燃料起到了關(guān)鍵的作用，

主宰差不多所有方式的交通。

Let's consider the electrical ?portion first.

The great news is that our technology is already advanced enough

to capture all that energy ?from renewables,

and there's an ample supply.

The sun continuously radiates

about 173?quadrillion watts ?of solar energy at the Earth,

which is almost 10,000?times our present needs.

It's been estimated that a surface that spans several hundred thousand kilometers

would be needed to power humanity at our present usage levels.

讓我們先來考慮電的部分。

好消息是，我們的技術(shù)已經(jīng)發(fā)展到了

可以捕獲從可再生資源那里得到的能量，

而且這種供給資源十分充足。

太陽持續(xù)放射

大約 173?萬億瓦特太陽能到地球，

這是大約我們目前需要的 1?萬倍。

據(jù)估計，幾十萬公里長的表面

應(yīng)該足夠提供我們?nèi)祟?目前使用水平的能量。

So why don't we build that?

Because there are other ?hurdles in the way,

like efficiency

and energy transportation.

To maximize efficiency,

solar plants must be located in areas ?with lots of sunshine year round,

like deserts.

But those are far away ?from densely populated regions

where energy demand is high.

There are other forms of renewable energy we could draw from,

such as hydroelectric,

geothermal,

and biomasses,

but they also have limits based on availability and location.

那為什么我們不去建造呢？

因為有其他阻礙，

例如效率

和能源運輸。

為了把效率最大化，

太陽能工廠必須建在 長年有充足陽光的地區(qū)，

例如沙漠。

但是那些地區(qū)離能量需求很高

的人口密集地區(qū)很遠(yuǎn)。

我們還有其他可再生資源可以考慮，

例如水力電氣，

地?zé)?/p>

和生物質(zhì)，

但是它們也有可獲取性和地域的限制。

In principle, a connected electrical energy network

with power lines crisscrossing the globe

would enable us to transport power from where it's generated

to where it's needed.

But building a system on this scale faces an astronomical price tag.

We could lower the cost by developing advanced technologies

to capture energy more efficiently.

The infrastructure for transporting energy would also have to change drastically.

原則上講，一個相連的電能網(wǎng)絡(luò)

通過在全球縱橫交錯的電線連接

可以讓我們把電從發(fā)電地

運輸?shù)接秒姷牡胤健?/p>

但是建造這種規(guī)模的系統(tǒng)需要 配備的價格標(biāo)簽卻是個天文數(shù)字。

我們可以通過發(fā)展高科技來降低成本，

以更有效率地捕獲能源。

運輸能源需要的基礎(chǔ)設(shè)施也 不得不發(fā)生巨大的改變。

Present-day power lines lose about 6-8% of the energy they carry

because wire material dissipates energy through resistance.

Longer power lines would mean more energy loss.

Superconductors could be one solution.

Such materials can transport electricity without dissipation.

Unfortunately, they only work if cooled to low temperatures,

which requires energy ?and defeats the purpose.

To benefit from that technology,

we'd need to discover ?new superconducting materials

that operate at room temperature.

當(dāng)今的電線會損失 百分之六到八的運輸電能，

是因為電線材料會通過電阻耗散能量。

電線越長意味著丟失的能量越多。

超導(dǎo)體可以是一種解決方式。

這種材料可以在沒有能量耗散 的情況下運電。

不幸的是，它們只在低溫環(huán)境下工作，

這就需要額外的能量來 控制溫度，結(jié)果適得其反。

為了在這個技術(shù)上獲益，

我們將需要發(fā)現(xiàn)可以在室溫下工作

的新型超導(dǎo)體材料。

And what about the all-important, oil-derived liquid fuels?

The scientific challenge there is to store renewable energy

in an easily transportable form.

Recently, we've gotten better at producing lithium ion batteries,

which are lightweight ?and have high-energy density.

But even the best of these store about 2.5?megajoules per kilogram.

That's about 20?times less than the energy in one kilogram of gasoline.

To be truly competitive, car batteries would have to store much more energy

without adding cost.

那基于石油的重要液體燃料怎么樣呢？

它的科學(xué)挑戰(zhàn)是把可再生能源

以容易運輸?shù)姆绞絻Υ妗?/p>

近來，我們已經(jīng)在生產(chǎn) 鋰離子電池方面大有進步，

它很輕而且擁有高能量密度。

但即使是最好的鋰離子電池 儲存的能量，每千克也只有2.5兆焦耳。

比一千克的石油提供的能量 低大約 20?倍。

要真正有競爭力，車用電池 需要儲存更多的能量，

而且不增加成本。

The challenges only increase ?for bigger vessels, like ships and planes.

To power a cross-Atlantic ?flight for a jet,

we'd need a battery weighing about 1,000?tons.

This, too, demands a technological leap towards new materials,

higher energy density,

and better storage.

One promising solution would be to find efficient ways

to convert solar into chemical energy.

This is already happening in labs,

but the efficiency is still too low to allow it to reach the market.

隨著載體變大，挑戰(zhàn)也就越大， 例如：船只和飛機。

給一架噴氣式飛機提供 橫跨大西洋飛行的能量，

我們需要一個重約 1000?噸的電池。

這個問題也需要技術(shù)上 的創(chuàng)新來發(fā)展新材料，

擁有更高的能量密度

和更好的儲存方式。

一個很有前景的解決方式 也許是想辦法高效地

把太陽能轉(zhuǎn)換成化學(xué)能。

這已經(jīng)正在實驗室里發(fā)生了，

但效率仍然太低，遠(yuǎn)不能滿足市場需求。

To find novel solutions, we'll need lots of creativity,

innovation,

and powerful incentives.

The transition towards all-renewable ?energies is a complex problem

involving technology, ?economics, and politics.

Priorities on how to tackle this challenge depend on the specific assumptions

we have to make when trying to solve such a multifaceted problem.

But there's ample reason to be optimistic that we'll get there.

Top scientific minds around the world are working on these problems

and making breakthroughs all the time.

And many governments and businesses are investing in technologies

that harness the energy all around us.

要找到更新穎的解決方式， 我們將需要很多創(chuàng)新，

革新，

和強大的激勵政策。

向全部可再生資源轉(zhuǎn)移 是一個復(fù)雜的問題，

它涉及到技術(shù)，經(jīng)濟和政治。

應(yīng)對這一挑戰(zhàn)的優(yōu)先次序取決于

我們在試圖解決這一多面問題時 必須做出的具體假設(shè)。

可是諸多理由讓我們樂觀地 相信我們可以做到。

世界頂級科學(xué)家們正在尋找 解決這些問題的方式，

而且一直在取得突破。

許多政府和企業(yè)也正在投資技術(shù)，

為我們創(chuàng)造源源不斷的能量。

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