How scientists turn lakes into giant batteries

翻译人员: Helen Chang 校对人员: Jiasi Hao

As of 2020, the world’s biggest lithium-ion battery

截至 2020 年， 全球最大的锂离子电池

is hooked up to the Southern California power grid

与南加州电网接通，

and can provide 250 million watts of power,

能够提供 2.5 亿瓦特的电力,

or enough to power about 250,000 homes.

足够为大约 25 万家庭供电。

But it’s actually not the biggest battery in the world:

但实际上 它并不是世界上最大的电池：

these lakes are.

这些湖泊才是。

Wait— how can a pair of lakes be a battery?

等—下—— 两座湖泊怎会是个电池呢?

To answer that question, it helps to define a battery:

了解电池的定义 则有助于回答这个问题：

it’s simply something that stores energy and releases it on demand.

电池只是个储存能量 并应需求而释放能量的东西。

The lithium-ion batteries that power our phones, laptops, and cars

为我们的手机、笔记本电脑和汽车 提供动力的锂离子电池，

are just one type.

只是电池的一种类型。

They store energy in lithium ions.

它们用锂离子储存能量。

To release the energy, the ions are separated from their electrons,

为释放能量， 锂离子与它们的电子分离，

then rejoined at the other end of the battery

然后在电池的另一头再次结合，

as a new molecule with lower energy.

成为能量较低的新分子。

How do the two lakes store and release energy?

两座湖泊如何储存和释放能量呢?

First, one is 300 meters higher than the other.

首先，一座湖比另一座高出 300 米。

Electricity powers pumps that move billions of liters of water

电力驱动水泵把数十亿升水

from the lower lake to the higher one.

从低湖转移到高湖。

This stores the energy by giving the water extra gravitational potential energy.

通过为水提供额外的重力势能 来储存能量。

Then, when there’s high demand for electricity,

然后，在电力需求量高的时候

valves open, releasing the stored energy by letting water flow downhill

打开阀门，让水往山下流 从而释放储存的能量。

to power 6 giant turbines that can generate 3 billion watts of power

这些能量 可为 6 个巨型的涡轮机提供动力，

进而持续 10 小时， 产生 30 亿瓦的电力。

for 10 hours.

We’re going to need more and more giant batteries.

我们将会需要越来越多巨型电池。

That’s because right now, generating enough electricity to power the world

那是因为目前供给世界 足够电力的发电方式

produces an unsustainable amount of greenhouse gas:

产生的温室气体量不可持续：

14 billion tons per year.

每年 140 亿吨。

We’ll need to get that number down to net-zero.

我们将需要把那个数字降到净零。

But many clean energy sources can’t produce electricity 24/7.

然而很多清洁能源无法全天候发电。

So to make the switch, we need a way to store the electricity until it's needed.

所以为实现这一转变， 我们需要一种能储电直到需要用电的方法。

That means we need grid-scale batteries:

这意味着我们需要电网规模的电池：

batteries big enough to power multiple cities.

大到足够为多个城市供电的电池。

Unfortunately, neither of the giant batteries we’ve talked about so far

不幸的是，我们已经 讨论过的两种巨型电池

can solve this problem.

都无法解决这个问题。

The two lakes setup requires specific geography, takes up a lot of land,

湖泊电池对地理位置有特定要求， 占用大片土地，

and has high upfront costs to build.

而且前期的建设成本很高。

The giant lithium-ion battery in California, meanwhile,

与此同时，加州的巨大锂离子电池

can power about 250,000 homes, yes, but only for an hour.

可以为大约 25 万家庭供电， 没错，但只能供电一小时。

Lithium-ion batteries are great for things that don’t use a lot of power.

锂离子电池 对于耗电少的东西非常有用。

But to store a lot of energy, they have to be huge and heavy.

但为了储存大量能量 锂电子电池就必须又大又重。

That’s why electric planes aren’t a thing:

这就是电动飞机仍不成气候的原因：

the best electric plane can only carry two people

目前最好的电动飞机只能载两个人，

for about 1,000 kilometers on one charge,

充电一次，大约能跑 10,000 公里，

or its batteries would be too heavy to fly.

要不然电池就重到飞不起来。

A typical commercial jet can carry 300 people over 14,000 km

典型的商用飞机能载 300 人， 飞行超过 14,000 公里

before refueling.

才需再加油。

Lithium-ion batteries also require certain heavy metals to make.

制造锂离子电池还需要若干重金属。

These resources are limited, and mining them often causes environmental damage.

这些资源有限， 而且开采过程往往会破坏环境。

Inventors all over the world are rising to the challenge

全世界的发明家奋起面对这一挑战：

of making batteries that can meet our needs—

发明能满足我们的需求的电池。

many of them even weirder than the two lakes.

其中，许多电池设计 甚至比湖泊电池更奇怪。

One company is building a skyscraper battery.

一家公司正在建造摩天大楼电池。

When the sun is shining, a crane powered by solar energy

当日光照耀时， 太阳能驱动的起重机

piles blocks on top of each other in a tower.

把一块块的积木相互堆叠于塔中。

At night, the cranes let gravity pull the blocks down

到了晚上，起重机让重力 将积木拉下来，

and use the resulting power to spin generators.

借此产生的能量驱动发电机。

Though there have been some early setbacks,

尽管早期遭遇了一些挫折,

another promising approach involves heating up salts until they melt.

另一种具有前景的方法是 加热盐直到熔化。

The molten salt can be stored until there’s a high demand for electricity,

熔化的盐 可保存至电力需求大的时候，

then used to boil water.

然后用来烧水。

The steam can power turbines that generate electricity.

蒸汽可以驱动涡轮机发电。

Another idea: bio-batteries made from paper, powered by bacteria,

另一个想法是制造生物电池纸， 由细菌提供动力，

and activated by spit.

由唾液激活。

Bacteria release energy in the form of electrons when they metabolize glucose,

细菌代谢葡萄糖时 以电子的形态释放能量，

and at least one species of bacteria can transfer those electrons

而且至少有一种细菌 能够把这些电子转移到细胞外，

outside its cells, completing a circuit.

形成完整的电路。

While these batteries won’t power a city, or even a house,

尽管这些电池无法 为一座城市，甚至一栋房子供电，

they don't have the waste and cost concerns of traditional batteries.

但它们没有传统电池的 废弃和成本顾虑。

From vast mountain lakes to microscopic bacteria,

从巨大的山湖到微小的细菌,

from seawater batteries that bypass the need for heavy metals

从无重金属需求的海水电池

to nuclear batteries that power deep space missions,

到为深空任务供能的核电池，

we're constantly rethinking what a battery can be.

我们不断反复思考 电池可以是什么样的。

The next unlikely battery could be hiding in plain sight—

或许下一个无法想象的电池 正隐藏在光天化日之下——

just waiting to be discovered and help us achieve a sustainable future.

就等着被发现， 帮助我们实现可持续发展的未来。