Iceland's secret power - Jean-Baptiste P. Koehl

翻译人员: jasmine lau 校对人员: Helen Chang

While the weather in Iceland is often cold, wet, and windy,

虽然冰岛的天气 总是寒冷、潮湿又多风，

a nearly endless supply of heat bubbles away below the surface.

但在地表之下，几乎 无穷无尽的热量在蒸发。

In fact, almost every building in the country is heated by geothermal energy,

事实上，这个国家几乎 所有建筑的供暖都来自于地热能，

in a process with virtually no carbon emissions.

这个过程中几乎没有任何碳排放。

So how exactly does this renewable energy work?

那么，这种可再生能源 到底是怎么回事呢？

Between the Earth’s core and its crust is a mixed layer

在地核和地壳之间，

是一个由固态和部分熔融的岩石 组成的混合层，称为地幔。

of solid and partially molten rock called the mantle.

Temperatures here range from 1,000 to 3,500 degrees Celsius.

这里的温度在1000 到3500摄氏度之间。

Some of this heat comes from the radioactive decay of metals.

其中一些热量来自金属的放射性衰变。

But much of it comes from Earth’s core,

但很大一部分来自地核，

which has been radiating energy since the planet formed

自从地球在40多亿年前形成，

over four billion years ago.

地核就不断地在辐射能量。

While the mantle moves slowly,

虽然地幔活动缓慢，

circulating roughly 40 kilometers below the Earth’s crust,

在地壳约40公里之下循环，

there are places where it surges closer to the surface.

但在有些地方，它会涌向地表。

Here, the magma forms pockets and veins in the ground,

在这里，岩浆在地面中形成囊和脉，

heating underground rivers and pools to temperatures reaching 300 degrees.

将地下河流和水池加热到300摄氏度。

Controlling heated water is at the heart of harnessing geothermal energy,

控制这些热水是利用地热能的核心，

and there are two primary models for how to do it.

而有两种主要方法能做到这一点。

One is to build a geothermal power plant

其中一种是建造地热发电厂，

which uses these hot, deep pools to produce electricity.

利用这些热的深水池发电。

First, engineers drill a well several kilometers into permeable rock

首先，工程师会在砂岩 或者玄武岩这样的可渗透岩石上

like sandstone or basalt.

钻一口数公里的井。

As the hot, highly pressurized groundwater flows into the well,

随着高温高压的地下水流入井中，

the rapid change in pressure and temperature

迅速变化的压力和温度

produces huge amounts of steam.

产生大量的蒸汽。

This steam then turns the blades of a turbine to generate electricity.

然后，这些蒸汽 将带动涡轮机的叶片发电。

Finally, the remaining cooled water and condensed steam

最后，剩余的冷却水 和冷凝蒸汽被注入地下，

are injected back into the ground to create an open loop

形成一个开环，

that provides electricity without losing water.

在不失水的情况下提供电力。

However, we don't have to drill this deep to take advantage of the planet's heat.

然而，我们不需要钻这么深的孔 来利用地球的热量。

Thanks to solar radiation,

多亏了太阳辐射，

dirt just 1.5 meters deep can reach temperatures over 20 degrees Celsius.

仅有1.5米深的泥土 就可达到20摄氏度以上。

Geothermal heat pumps pipe water or antifreeze liquid

地热热泵将水或者防冻液体

through this layer of earth to siphon its energy.

通过管道在这层泥土里抽取能量。

These liquids are then pumped through local infrastructure,

然后，这些液体被泵送到 当地的基础设施中，

dispersing their heat before moving back through the ground

扩散它们的热量， 然后再次在地面中穿梭

to absorb more energy.

吸收更多的能量。

While external electricity is needed to operate the pumps,

尽管运作泵需要外部电力，

the energy provided is far greater than the energy used,

但从中提供的能量远远超过消耗的，

meaning this process is also a sustainable loop.

这代表这个过程 也是一个可持续的循环。

In fact, geothermal heat pumps are both cheaper to operate

事实上，地热泵不仅运行成本低，

and at least two times more energy efficient than fossil fuel equivalents.

它的节能性是化石燃料的两倍。

Whether geothermal energy is radiating just below our feet,

无论地热能是在我们脚下放射，

or heating water several kilometers deep,

还是在几公里之下加热水，

the planet is constantly radiating heat.

地球都不断地辐射能量。

Averaged across one year,

平均一年，

Earth gives off roughly three times more energy than humanity consumes.

地球释放的能量 大约是人类消耗的三倍。

So why does geothermal only account for 0.2% of humanity’s energy production?

那么，为何地热能只占 人类能源生产的0.2%呢？

The answer has to do with heat, location, and cost.

答案和热量、地点和成本有关。

Since geothermal heat pumps rely on the consistent heat

由于地热热泵依赖 来自于浅地层的持续热量，

found in shallow earth,

they can be implemented almost anywhere.

它们几乎可以在任何地方使用。

But geothermal power plants require tapping into

但是，地热发电厂需要利用

high-temperature geothermal fields;

高温地热田；

regions hotter than 180 degrees and typically several kilometres underground.

温度超过180度的地区， 也通常在地下几公里。

These high temperature zones are hard to find,

这些高温地区很难找到，

and drilling this deep for just one of the several wells a plant will need

而钻这么深仅仅为了一个工厂 需要的几口井中的其中一口，

can cost up to $20 million.

就需要花费2000万美元。

There are regions with shallower geothermal fields.

有些地区的地热田较浅。

Iceland and Japan are near active volcanoes and tectonic plate boundaries,

冰岛和日本临近活火山 和地壳板块的边缘，

where magma rises up through the crust.

在那里岩浆从地壳中上升。

But these same factors also make those regions prone to earthquakes,

但这也导致这些地区容易发生地震，

which can also be triggered by intensive drilling.

而密集的钻井也会引发地震。

Furthermore, while geothermal energy is clean and renewable,

此外，尽管地热能是干净、可再生的，

it’s not entirely harmless.

它并不是完全无害的。

Drilling can release vapors containing pollutants

钻井会释放出含有污染物的蒸汽，

like methane and hydrogen sulfide.

例如甲烷和硫化氢。

And drilling tools that use pressurized water can contaminate groundwater.

使用高压水的钻井工具 也会污染地下水。

Fortunately, new technologies are emerging to meet these challenges.

幸运的是，新技术的出现 能够战胜这些挑战。

Emission control systems can capture pollutants,

排放控制系统可以捕获污染物，

and electromagnetic monitoring can help detect seismic risks.

电磁检测可以帮助检测地震风险。

We're also uncovering entirely new sources of geothermal energy,

我们也在发现全新的地热能来源，

like pockets of magma in mid-ocean volcanoes.

比如海洋中火山的岩浆区。

So if we can safely and responsibly tap into the heat sustaining our planet,

因此，如果我们能够安全、 负责任地利用地球的热量，

we might be able to sustain humanity as well.

我们或许能够维持人类的生存。