『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 74 Lec2听力练习：What condition must exist in order to use ocean tides to generate electricity?原文题目答案解析，TPO/Official 74 Lec2听力原文范文音频翻译。

托福TPO/Official 74 Lec2听力原文What condition must exist in order to use ocean tides to generate electricity?【新东方在线】

旁白：听一段环境工程课上的讲座内容。

Narrator：Listen to part of a lecture in an environmental engineering class.

讲师：好的。我们已经讨论过可再生能源作为一种替代的发电方式。

Instructor：Okay. We've talked about renewable energy as an alternative way of generating electricity.

替代什么呢？替代不可再生能源，比如煤炭、石油或天然气，这些能源我们最终会耗尽，因为我们的消耗速度比它们的再生速度快。

Alternative to what? To non-renewable energy such as coal or petroleum or natural gas, something that we'll eventually run out of because we're consuming it at a faster rate than it's being regenerated.

好的。那么我们主要的可再生能源来源是什么？肯？

Okay. So what's our primary source of renewable energy? Ken?

讲师：是的，但利用太阳能发电并不容易，因为什么呢？

Instructor：Yes, but it's not so easy to use it to generate electricity because?

学生1：而且在经常多云的地方，它的效果也不太好。

Student 1：And it doesn't work very well in places where it's cloudy a lot of the time.

讲师：没错。而且太阳能也不容易捕捉。

Instructor：That's right. And the sun's energy is not that easy to capture.

我们正尝试使用叫做太阳能电池的巨大面板来捕捉阳光，并将其转化为电能。

We're trying to use giant panels called solar cells to capture the sun's rays and convert them into electricity.

我们已经取得了一些成功，但这么说吧，在美国将太阳作为主要能源来源的想法，就像有人曾经说过的，有点像太阳本身，又大又亮，但比看起来要遥远。

And we've had some success, but well, let's just say that the idea of using the sun as the principal source of energy in the United States is, well, as someone once said, it's kind of like the sun itself, big and bright but further away than it seems.

好的。现在我们来谈谈海洋作为另一种可再生能源来源。

Okay. Now let's talk about the ocean as another source of renewable energy.

海洋有两种我们可以利用的机械能，潮汐能和波浪能。

The ocean has two kinds of mechanical energy that we can use, the tides and the waves.

为了利用潮汐发电，涨潮和落潮之间的落差必须至少有5米，也就是大约16英尺。

In order to use tides to generate electricity, the difference between high and low tide has to be at least five meters, or about 16 feet.

地球上只有大约40个地方有这样的潮汐范围，而且实际上世界上只有一座真正大型的潮汐能发电站。

There are only about 40 places on the planet with that kind of tidal range, and there's actually only one really big tidal energy power station in the world.

它在法国。有什么问题吗，苏珊？

学生2：那么他们会像在一些河流上那样建一座水坝吗？

Student 2：So do they build a dam like they do on some rivers?

讲师：是的。他们在海湾上建一座水坝，水坝里有闸门和涡轮机。

Instructor：Yes. They build a dam across a bay, and they have gates and turbines in the dam.

当潮汐使得水坝两侧的水位产生所需的落差时，闸门就会打开，水流被迫通过涡轮机，涡轮机带动发电机，从而产生电力。

And when the tides produce the required difference in the water level on opposite sides of the dam, the gates are opened and water is forced through the turbines, which turn a generator, which produces electricity.

好的。那么波浪能呢？我们可以使用两种电力系统将波浪中的能量转化为电能。

Okay. So what about the waves? There are two kinds of power systems we can use to convert the energy in waves into electricity.

一种是我们所说的离岸系统，在这种系统中，设备安装在深水中，漂浮在公海的波浪上。

There is what we call an offshore system, where you have devices that are installed in deep water that float on the waves in the open sea.

另一种是我们所说的近岸系统，在这种系统中，设备安装在海岸线沿线，用来从拍岸的波浪中提取能量。

And then you have what we call an onshore system, where you install your devices along the shoreline to extract the energy from waves that are breaking on the shore.

And there are several varieties of these systems.

讲师：是的，大多数人都没听说过，因为波浪能和潮汐能很像。

Instructor：No, most people haven't because wave power is a lot like tidal power.

世界上只有少数几个地方适合利用波浪来发电。

You only have a handful of places in the world where it's practical to use waves to produce electricity.

所以在试图利用海洋的机械能方面存在一个根本性的问题。有什么问题吗，肯？

So there is a fundamental problem with trying to harness the ocean's mechanical energy. Yes, Ken?

学生1：利用海洋中的热能怎么样？有人尝试过吗？

Student 1：What about using the heat energy in the ocean? Has anybody tried to do that?

我的意思是，我知道海洋必须从太阳那里吸收大量的热量。

I mean, I know the ocean has to absorb a lot of heat from the sun.

讲师：嗯，是的，有人尝试过。事实上，我们有一种叫做海洋热能转换的过程，简称OTEC，用来将这种热量转化为电能。

Instructor：Well, yes, they have. As a matter of fact, we have a process called ocean thermal energy conversion, or OTEC, to convert that heat into electricity.

海洋覆盖了地球表面70%以上的面积，它就像一块巨大的太阳能电池板，一块巨大的太阳能电池，收集太阳能并升温。

The ocean covers more than 70% of earth's surface, and it's like a huge solar panel, a huge solar cell collecting solar energy and heating up.

太阳对表层水的加热比对深海海水的加热要多得多，这种温差产生了热能。

The sun warms the surface water a lot more than the deep ocean water, and that temperature difference creates thermal energy.

当表层水和深层水之间的温差约为20摄氏度时，海洋热能转换的效果最好。

Ocean thermal energy conversion works best when the temperature difference between the surface water and the deeper water is about 20 degrees centigrade.

很多热带地区都有这样的条件。

You have those conditions in a lot of tropical areas.

实际上，利用海洋热能的想法可以追溯到很久以前。我记得第一个OTEC系统是在1930年左右建成的。

Actually the idea of tapping the thermal energy of oceans goes way back. The first OTEC system was built around, I think it was 1930.

不幸的是，OTEC系统非常昂贵。不过，有些能源专家认为，如果我们能想办法提高它们的效率，它们未来可能会成为主要的能源来源。

Unfortunately, OTEC systems are very expensive. Still, there are some energy experts who believe that they might be a major power source in the future if we can figure out how to make them more efficient.

而且OTEC可能还有一个显著的附带好处。海水中溶解了许多有价值的矿物质。

And OTEC might have a significant side benefit. There are a number of valuable minerals dissolved in ocean water.

但当他们研究从海洋中开采、提取矿物质的可能性时，他们总是说这不可行，因为成本太高。

But when they have studied the possibility of mining, extracting minerals from the ocean, they've always said it wasn't feasible because it would cost too much money.

一是要抽取所有的海水，二是要提取这些元素。

One, to pump all that ocean water, and two, to extract the elements.

但如果有OTEC工厂已经在抽取海水，你就不用担心这部分成本了。你只需要想办法降低提取成本就行了。

But if you have OTEC plants already pumping the water, you don't have to worry about that cost. You just have to figure out how to reduce the cost of extraction.

What is the professor's opinion about solar energy?

What condition must exist in order to use ocean tides to generate electricity?

Why does the professor compare the ocean to a solar panel?

What does the professor imply about the ocean's thermal energy?

According to the professor, how might OTEC systems facilitate the extraction of minerals from ocean water?

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