評論
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Narrator:Listen to part of a lecture in an environmental science class.
獨白:聽下面一段關于環境科學課的講座。
Professor:All right folks, let's continue our discussion of alternative energy sources and move on to what's probably the most well-known alternative energy source-solar energy.
教授:好了，我們繼續討論可再生能源。這次來講講大概是最眾所周知的再生能源—太陽能。
The sun basically provides earth with virtually unlimited source of energy every day, but the problem has always been how do we tap this source of energy.
太陽能每天都為地球提供實實在在的可再生能源，問題就是我們如何有效地利用它。
Can anyone think of why it's so difficult to make use of solar energy?
有人能想到為什么太陽能這么難以利用嗎？
Student:Because it is hard to gather it?
學生:因為很難收集？
Professor:That's exactly it.
教授:完全正確。
Solar energy is everywhere, but it's also quite diffused.
太陽能到處都是，但同時又很分散。
And the thing is the dream of solar energy is not a new one.
而且利用太陽能的夢想并不是新鮮事。
Humanity has been trying to use the sun's light as a reliable source of energy for centuries.
人類試圖利用太陽能作為可信賴的能源已經好幾個世紀了。
And around the beginning of the 20th century there were actually some primitive solar water heaters on the consumer market.
而且在 20 世紀初期，市面上出現了一些太陽能熱水器，
But they didn't sell very well. Any of you want to guess why?
但銷量不好。有人能猜到原因嗎？
Student:Well, there were other energy choices like oil and natural gas, right?
學生:嗯，因為有類似天然氣這種其他的資源可供選擇？
Professor:Yeah. And for better or for worse, we chose to go down that path as a society.
教授:對。而且不論好壞，我們的社會也選擇了這條路。
When you consider economic factors, it's easy to see why.
當你考慮經濟因素的時候理由就顯而易見了。
But then in the1970s, there was an interest in solar energy again.
但是在 20 世紀 70 年代的時候，對太陽能的熱情又回來了。
Why do you think that happened?
為什么會發生這樣的事呢？
Student:Because oil and natural gas were...err...became scarce?
學生:因為石油和天然氣變得稀缺的原因？
Professor:Well, not exactly.
教授:也不盡然。
The amount of oil and natural gas in the earth was still plentiful, but there were other reasons.
地球上的石油和天然氣資源還很充足。但另有原因。
It's a political thing really and I'm gonna get into that now.
這其實是個政治問題，我現在不打算解釋。
So what happened in the 1970s was oil and natural gas became very expensive very quickly, and that spurred people to start looking into alternative forms of energy, solar energy probably being the most popular.
20 世紀 70 年代的時候，石油和天然氣的價格飆升，使得人們開始尋找別的能源，太陽能是最受推崇的。
But then in the 80s, this trend reversed itself when the price of oil and natural gas went down.
但在 80 年代，這股潮流被逆轉了，因為石油和天然氣的價格回落了。
Alright let's shift our focus now to some of the technologies that have been invented to overcome the problem of gathering diffused solar energy.
好了，現在我們轉而看看為了克服收集分散太陽能這個困難而發明的一些技術。
The most basic solution is simply to carefully place windows in a building, so the sun shines into the building and then it's absorbed and converted into heat.
最基本的辦法很簡單，就是往樓里放窗戶，這樣太陽光就可以被吸收然后轉化成熱量。
Can anyone think of where this is most commonly used?
有人能想到在什么地方被廣泛應用嗎？
Student:Greenhouses.
學生:溫室。
Professor:Yep, greenhouses where plants are kept warm and provided with sunlight because the walls of the building are made entirely of glass.
教授:對。溫室里的植物之所以保持著溫度就是因為它的墻壁是玻璃。
But we do also have more complex systems that are used for space heating and they fall into two categories, passive and active heating systems.
但我們也有更加復雜的供熱系統，它們分為被動和主動供熱系統。
Passive systems take advantage of the location or design of a house.
被動供熱系統主要利用的是房子的位置和設計。
For example, solar energy is gathered through large glass panels facing the sun.
比如說，太陽能被面對太陽的巨大的玻璃板所吸收。
The heat is then stored in water-filled tanks or concrete.
熱量就被存儲在了裝滿水的容器或者混凝土中。
No mechanical devices are used in passive heating systems.
在被動供熱系統中，沒有機械裝置，涉及到很少和幾乎沒有的機械輔助。
They operate with little or no mechanical assistance. With active systems, on the other hand, you collect the solar energy at one location, and then you use pumps and fans to move heat from the collectors through a plumbing system to a tank, where can be used to heat a home or to just provide hot water.
然而，對于主動供熱系統，你可以先在一個地點收集太陽能，然后利用泵和風扇通過管道系統轉移到容器中，它可以提供熱水。
Student:Excuse me professor, but I've got to ask, how can solar energy work at night or on cloudy days?
學生:打擾一下，教授，但是我想問一下，太陽能如何在晚上和陰天工作呢？
Professor:That's...Well...that is a really good question.
教授:這是個很好的問題。
As a matter of facts, science is still working on it, trying to find ways of enhancing energy storage techniques so that coming of night or cloudy days really wouldn't matter.
事實上，科學家們還在努力解決這個問題。他們試圖加強存儲的技術，這樣夜晚和陰天就不構成影響。
That is the biggest drawback to solar energy.
這是太陽能的最大缺陷。
The problem of what do you do in cases where the sun's light is weak or virtually non-present.
當太陽光變弱或者不存在時，人們該何去何從。
So the storage of solar energy, lots of solar energy, is a really important aspect.
所以從這個角度講，大量的太陽能儲蓄是必要的。
Student:Does that mean that solar energy can only be used on a small scale, like heating a home?
學生:這是不是意味著太陽能只能小規模使用呢，比如家庭供暖？
Professor:Well actually, there have been some attempts to build solar energy power plants.
教授:事實上，有些人嘗試過建造太陽能發電站。
The world's largest solar plant is located in Cremer Junction California. It can generate 194 megawatts of electric power, but that's just a drop in the bucket.
世界上最大的太陽能發電站坐落在加利福尼亞的 Cremer、它可以發 194 兆瓦電力，但這只是滄海一粟。
Right now the utility companies are interested in increasing the capacity of Cremer Junction Plant, but only time will tell if it will ever develop into a major source of power for that region, considering the economic and political factors involved.
現在各公司有興趣擴大 CremerJunction 發電站的規模，但考慮到當地的經濟和政治影響，只有時間能告訴我們，太陽能是否會成為當地的主要能源。
