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电网准备好迎接绿色能源了吗?

Is the Power Grid Ready for Green Energy?

This episode is sponsored by Wren,
本集内容由Wren赞助呈现
a website with a monthly subscription
Wren是一家可按月订阅的
that helps fund projects to combat the climate crisis.
为应对气候危机的项目提供资助的网站
Click the link in the description to learn more about how you can make a monthly contribution
点击详情里的链接 了解如何每月
to support projects like rainforest protection programs.
为支持如雨林保护计划等项目捐款
[♪ INTRO]
[前奏音乐]
Green energy is not a new idea.
绿色能源并非一个新话题
The US has harvested electrical power from water since the 1880s;
美国自19世纪80年代就开始用水力发电
almost a decade later, there was also an electric wind turbine in Cleveland.
将近10年后 克利夫兰市建起了风力发电机
And now there’s a whole bunch of other types of renewables.
如今又出现了很多其他种类的可再生能源
But even though we started at this pretty early,
尽管我们很早就开始使用可再生能源
renewables have been kind of in the background for multiple reasons,
但由于种种原因 未能大规模投入使用
like they can stop and start at any moment.
比如说 它们可以随时停止或开始
For example, when the wind suddenly gusts or when the clouds cover the sun.
举个例子 狂风大作或乌云蔽日的时候
This interruption doesn’t happen all that often with ol’, reliable coal,
而烧煤就不存在这些干扰因素
which is why it has been the grid’s backbone since forever.
这也是煤炭能一直做电网支柱的原因
When you want more power, just burn more coal.
你需要更多电力 就烧更多的煤
And our electric grid was built around that simplicity.
我们电网建立的基础就是这么简单
But the world has gotten increasingly complicated,
但世界变得越来越复杂
and now it is time to adapt.
是时候改变了
How electricity is generated and transmitted is
电力的生产和传输
critical for building a green energy-friendly grid.
对建立绿色能源友好型电网至关重要
But to understand how all of that works,
但要理解电网的运转原理
we need to zoom in on a traditional power plant.
我们要先仔细了解一下传统的发电厂
Pick your favorite: Coal, nuclear, biomass, oil, whatever.
选一个你喜欢的:煤炭 核能 生物质能 石油 不管哪个
They all work in a similar way
他们的运行原理都差不多
because of something Michael Faraday discovered.
都以迈克尔·法拉第理论为基础
If you move a magnet and a wire near one another,
如果你用一块磁铁靠近电线
it produces electricity in the wire.
电线中就会产生电流
Every traditional power plant has a generator:
每个传统的发电厂都有发电机
Wires that can spin in a circle near a strong magnet,
电线在强力磁铁周围绕圈旋转
or a magnet that can spin near wires.
或磁铁绕着电线旋转
Either way, the generator spins, and the electricity flows through the wire.
无论哪种方式 发电机一转 就会有电流通过电线
If you take that wire and move it towards the magnet’s north pole,
如果将电线移动至磁铁北极
electricity will flow in one direction through the wire,
电流将通过电线朝一个方向流动
just like Faraday discovered two hundred years ago.
就像法拉第200年前发现的那样
And if you move that same wire away from the north pole,
如果你将电线从北极移开
electricity will flow in the opposite direction.
电流会朝相反方向流动
This cycle repeats over and over again in the generators as they spin,
旋转过程会在发动机内一遍遍循环往复
creating what’s called an alternating current, or AC,
电流不停转换方向
because the current alternates directions.
交流电就这样产生了
In addition to AC, there is also DC, or direct current,
除了交流电 还有直流电
where charge only moves in one direction along the wire.
直流电沿电线只朝一个方向流动
And speaking of currents, that’s one of the two components of electricity,
说到电流 它是电的两个组成部分之一
the other being voltage.
另一个是电压
In a broad sense, voltage measures how much energy is available,
广义上讲 电压表示有多少电量可用
and current measures how much energy is used.
电流表示使用了多少电量
That’s a simplified explanation, so do not write it on your physics final,
这是简化后的定义 物理期末考试可别这么写
but it’ll get us where we need to go.
但这能让我们理解后面的内容
When we send electricity from one place to another,
我们把电从一处送往另一处的时候
the goal is to keep energy loss at a minimum.
目标就是要将能耗降到最低
Because the more we waste energy,
因为浪费的能源越多
the more fuel we have to use to turn on the same number of lights.
打开同等数量的灯所需的燃料就越多
So, before sending electricity on a long journey,
所以 在长途输送电力前
the current goes through a transformer,
电流会先通过一个变压器
which changes low-voltage,high-current AC from the generator
将发电机发出的低电压 高强度交流电
to high-voltage,low-current AC for transmission.
转化为高电压 低强度的交流电再传输
To sum up, this is what happens at a traditional power plant:
总结一下 传统发电厂是这样运转的
Something hot boils water.
先把水煮沸
That water vapor pushes a turbine which turns a generator,
水蒸气推动涡轮 涡轮启动发电机
which creates an alternating current,
发电机发出交流电
which goes through a transformer to raise its voltage,
交流电通过变压器提高电压
which helps preserve energy.
从而减少能耗
Some energy is still wasted as heat,
由于电荷沿着电线流动
since charges moving along the wires,bump into atoms
与原子发生碰撞 致其振动 产生了热量
and get them jiggling, and create heat.
所以能源还是会以热量的形式出现损耗
So every once in a while, transmission wires go into substations
每隔一段时间 输电线路进入变电站
that combine power from different sources and fix the voltage with more transformers.
整合不同来源的电力 用更多的变压器固定电压
And if electricity still has a ways to go, they nudge it back up.
如果电力还要继续输送 它们还能助推一把
Now if it’s close to businesses or homes, where it will actually be used,
当电力传输到用电终端附近 比如企业或住家
they drop it down, so we won’t interact with anything that’s too dangerous.
电压就会降 这样我们就触碰不到太危险的东西了
All of these systems, cycles, and stations have to work together in sync,
所有这些系统 循环和站点都需同步运行
which is why we’ve traditionally relied so much on coal
所以我们一直以来都非常依赖煤炭
and, more recently, nuclear power.
近年来则是核能
Because we know how much energy to expect from both of them.
因为我们清楚它们的发电能效
That means that as grid computers and engineers figure out
这就意味着当网格计算机和工程师了解
how much electricity different areas will need,
不同地区的用电需求后
they don’t have to worry about whether the source will make as much as expected.
他们不必担心发电厂会供电不足
Now some renewables can slot right into that system.
现在一些可再生能源可直接适用于那套系统
Wind turbines and hydropower plants both contain generators,
风力涡轮机和水电站里都有发电机
just like the ones you find in a traditional power plant.
和传统发电厂里的一样
They’re just spun by wind or liquid water, making the same alternating current that
不过是用风力和水力带动旋转 产生同样的交流电
can be adjusted by the same kind of transformers in traditional plants.
然后用和传统发电厂一样的变压器进行调节
Now if the power is coming from a reservoir that’s built up behind a dam,
如果电力是从建于水坝后的水库发出的
water can flow through and produce power when there’s extra demand,
那有额外需求时 可以开闸放水来发电
but it can also be stopped and stored up when the grid is fine without that help.
电网供电充足时 也可以关闸储水
Wind power, though, is trickier.
而风能的情况更复杂
Some places are pretty windy,
有些地方多风
but nowhere is always windy, even over the ocean.
但没有地方会天天有风 即使是海上
And even small differences in wind speed from one minute to the next
即便是瞬息之间一点点的风速变化
can lead to big differences in how much electricity is generated.
都会极大地影响发电量
So, it’s not as simple as just letting more turbines spin when we need more power.
所以并不是需要发电就让涡轮机旋转那么简单
Relying on wind power also adds another variable
依赖风力还会给已经很复杂的系统
into the already very complicated system.
增加另一个变数
Because engineers, in addition to estimating demand,
因为除了预估供电需求
now have to estimate the amount of power available.
工程师们还需要评估可用的电量
In other words, they need to forecast the humans, the weather,
也就是说 他们需要预测人 天气
and how the humans will respond to that weather.
以及人会对天气做出的反应
And the same is true for a lot of renewables.
这对很多可再生能源都是同样成立的
Droughts, clouds, and nighttime mean that
干旱 云朵和夜晚意味着
electricity from these sources cannot be uniformly reliable.
这些能源提供的电力并不是持续稳定的
Power companies assume you’re still going to want electricity
电力公司知道即便是阴天
even when the sun isn’t out,
大家还是要用电
so they make up the difference with something more dependable: Fossil fuels.
所以需要更稳定的能源来填补空缺:化石燃料
Now, this is a common critique of renewable energy:
对于可再生能源 存在一个普遍的质疑
What do you do when the wind stops blowing?
风停了怎么办?
And there aren’t many great answers right now,
即便是高度依赖风能的国家
even in countries that rely heavily on wind power.
对于这个问题也没有很好的答案
And the same goes for any other intermittent power source.
而其他不稳定的能源同样会存在这些问题
The challenge is that it’s easy to have a little bit of renewables,
可再生能源要少量拥有并不难
but it’s hard to have a lot of them.
难的是大规模储存拥有
The grid just isn’t set up to have so many different sources going into it,
电网并不是为了适应多种能源而造
especially when the amount of electricity from those sources isn’t under our control.
特别是这些能源的发电量不受控的时候
But engineers are working on it.
但是工程师们正在研究这个问题
One of the major avenues of research involves ways of storing extra energy
研究的主要方向之一就是储存额外能源的方法
produced on particularly windy or sunny days
尤其是在多风天和晴天产生的能源
so that it can be used later on in the form of batteries.
让其日后能以电池方式来使用
A big enough battery would kick on when the wind stops, smoothing out the supply
等风一停 大块电池就启动
smoothing out the supply that goes to the rest of the grid
将电稳定输送到电网其他地方
and removing that extra variable.
消除供电的额外变数
But even the best batteries in the world would need to be huge
但即使是世界上最好的电池也要足够大
to store enough energy to power your home for a long time.
才能储存足够的能源为你家长期供电
They’d weigh about a ton,
这些电池重约一吨
and if they had to be replaced as often as other high-capacity batteries do,
如果它们必须像其他高容量电池一样经常更换
they’d cost more in the long run to consumers and utilities
那长远来看 对消费者和供电公司来说
than electricity from other sources,
它们会比其他来源的电力花费更多
even if all the energy going into the battery were free.
即便电池里的能源都是免费的
Engineers around the world are searching for materials that they can
全世界的工程师们都在寻找能制作
use to make bigger, cheaper, longer-lasting batteries.
更大 价格更低 寿命更长电池的材料
But our current batteries are proving hard to beat.
但目前很难找到更好的选择
Now this has not stopped some people
这并没有阻碍一些人
and even some whole towns from going all-in on battery power.
甚至有些全镇都在使用电池供电
In one town in Colorado, every house has solar panels,
在科罗拉多州的一个小镇 每家都有太阳能板
a household battery, and an electric car charger.
家用电池 以及电动汽车充电桩
So each home is able to move energy between batteries and outlets,
所以每家都可以根据太阳能板收集的能量
depending on how much is coming in through the panels.
在电池和插座间切换电源
And the homes have wires between them, too,
此外 每家之间还有电线相连
so that electricity can be automatically redistributed to wherever it’s needed most.
这样电力就能自动重新分配到最需要它的地方
Towns like these form one kind of microgrid:
这样的小镇形成了一种微电网
A little section of the electric grid that can be disconnected
在紧急情况下 小面积电网
from the rest during emergencies without losing power.
会与其他部分断开 但不会断电
More and more microgrids are popping up around the US and around the world,
随着社区在当地产出并储存更多的电力后
as communities make and store more electricity locally.
越来越多的微电网在美国和世界各地涌现出来
Ultimately, many engineers think that the solution to our renewable woes will be a
最终 多数工程师们认为解决可再生能源困境的方法
combination of microgrids and their exact opposite:
是将微电网和与其完全相对的
More long-distance transmission wires that can move electricity between regions.
长距离输电线路结合 来调度地区间用电
The more we have of both,
这两者越多
the more the grid as a whole will act like that town in Colorado:
那电网作为一个整体 会像科罗拉多州的那个镇一样
Each region will be able to operate on its own most of the time,
大部分时间各地区可以独立运行
but if something goes wrong, we have each other’s backs.
但有意外情况时 可以互相支持
Other places have also gotten creative with the definition of “battery.”
其他地方也对“电池”进行了创意定义
Normally, hydroelectric dams will produce electricity
通常情况下 水电站让湖水倾泻而下
just by letting water from the lake flow downhill and turn the generators.
带动发电机 完成发电
But some will turn their generators into motors
但当电网中有多余的能量时
when there’s extra energy in the grid,
一些电厂会将发电机变为马达
so that the plant can pump the water back up into the lake.
这样就可以将水再抽回湖里
That way, the entire lake acts like a big battery:
那样的话 整个湖就像一个大电池
It stores energy when there’s a surplus and releases it when there’s a demand.
储存多余的电量在需要时使用
Then there are the solar panels themselves, which lead to some unique problems.
然后是太阳能板本身 也会引起一些独有的问题
Just about every source of electricity in the world
几乎世界上的每种发电能源
uses some sort of generator, but not solar panels.
都会用到某种发电机 但不一定会用太阳能板
They just sit in the sunlight,
太阳能板被置于阳光下
which knocks electrons off of atoms in the panels and sends them down wires.
原子中的电子被阳光击中后被输送到电线里
Which means that solar panels create DC electricity,
这意味着 太阳能板产出的是直流电
where the current goes in one direction, as opposed to the AC of the rest of the grid.
电流都朝一个方向移动 与其余电网的交流电相反
If you plugged solar panels directly into the grid,
如果把太阳能板直接接入电网
either the panels would fry or the grid would.
太阳能板或电网会被烧坏
And the same goes for batteries.
接入电池也一样
So, if you were to supply energy to the grid,
所以 如果你要向电网供电
then DC needs to change to AC to fit with the rest of the system,
需将直流电转成交流电来适应其余系统
which isn’t too hard to do,
而这并不难实现
but that’s not the end of AC/DC headaches.
但这不是直流电和交流电难题的终点
When more solar is fed into the grid,
当更多的太阳能被输入电网时
we run into a surprisingly mechanical problem.
我们就遇到了一个出人意料的机械故障
Traditional generators need to keep turning at a constant rate,
传统发电机需要保持恒速旋转
keeping the power supply stable.
来持续稳定地供电
But here’s the thing: they are physically turning.
但问题是 它们旋转的时候
And that helps because moving objects have inertia,
因为运动中的物体有惯性
meaning that unless something outside stops it, it’ll keep going.
意味着若无外力介入 它会一直转
So if something happens at the power plant,
如果发电站出状况
and there isn’t steam to push the generator anymore, it doesn’t just stop.
没有蒸汽推动发电机的话 发电机就不会停
It keeps spinning.
它会继续转
It’ll be, like, a few seconds before there are any noticeable effects,
几秒钟后才会有明显的效果
and that’s enough time for a power plant to adjust how much it’s burning
这几秒足以让发电站调整发电量
or call for backup from elsewhere if there’s a problem.
或在问题出现时从别处寻求支援
So, this inertia helps keep the grid in sync.
所以 惯性使电网保持同步
It makes it so that if there are problems,
这样一来 如果出现问题
there isn’t a big cascade of,like, sudden power shutoffs everywhere.
就不会出现大规模的连锁反应 比如 到处突然断电
But, generally, the devices that turn DC into AC are not mechanical.
但通常来说 将直流电转化为交流电的设备不是机械的
They’re electronic.
而是电子的
So, there’s no inertia there to help smooth out the temporary blips.
所以就没有惯性来帮助消除短暂波动的影响
The more our electricity comes from solar panels and batteries,
我们使用太阳能和电池供电越多
the more systems need to be put in place
要建立的系统就越多
that actively monitor electricity from all corners of the grid
这样才能积极监测电网各个角落的电力
to make sure momentary hiccups don’t cause that cascade of problems.
确保短暂的故障不会引发一连串的问题
All of these changes mean that
这些改变都意味着
if we keep getting more electricity from renewable resources
如果我们继续使用更多可再生能源发电
parts of the grid need to become more interconnected and self-reliant.
电网各区域就要有更好的互通性和独立性
They need to be more stable and more flexible and
各区域要更稳定灵活
have the ability to store energy for themselves and share it freely.
并拥有自己储存和自由共享的能力
They all need to monitor one another without any system stepping on another’s toes.
在互不影响的前提下对对方进行监测
Like I said, this is not simple.
就像我说的 这并不简单
But in the year 2000, the National Academy of Engineers rated
但在2000年 美国国家工程学院
the development of global electrical grids as the
将全球电网的发展评为
greatest engineering achievement of the twentieth century.
二十世纪最伟大的工程技术成就
Perhaps adapting to a changing world with changing energy sources
可能适应不断变化的世界和能源
will be one of the greatest achievements of the twenty-first.
将会是二十一世纪最伟大的成就之一
And if you would like to keep changing the world for the better
如果你想让世界变得更好
you might want to check out today’s sponsor WREN.
可以了解下今天的赞助商WREN
They are a website with a monthly subscription that helps to
他们是一家可按月订阅的
fund projects to combat the climate crisis.
为应对气候危机的项目提供资助的网站
Wren searches around the globe for promising projects,
Wren在全球范围内寻找有前景的项目
getting data on the ground to track their impact over time.
实地获取数据来跟踪项目的长期影响
Like one of their projects seeks to help prevent wildfires in California
比如 他们有个项目是通过移除枯死且易燃的树木
by removing dead and flammable trees and turning the tree biomass into biochar.
将树木的生物质能转化为生物炭 来预防加州的野火
Over the long term we need governments to fund these projects,
长远来看 我们需要政府来资助这些项目
but we can start by crowdfunding them.
但我们可以先从众筹开始
And as a bonus, we’ve partnered with Wren to protect an extra ten acres of
作为回报 我们已经与Wren合作
to protect an extra ten acres of rainforest
为前100名使用我们详情链接注册的用户
for the first 100 people who sign up using our link in the description!
额外保护10英亩雨林
And as always, thanks for supporting SciShow.
和往常一样 感谢支持SciShow
[♪ OUTRO]
[结束音乐]

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视频概述

电网的发电能源有很多种,新的绿色能源和传统能源在发电原理上有什么不同呢?它们又存在哪些问题呢?这个视频会帮助我们了解绿色能源对电网发展的影响。

听录译者

收集自网络

翻译译者

蓝慢慢

审核员

审核员FL

视频来源

https://www.youtube.com/watch?v=dIMBr_uTPkE

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