Alternative energy

可替代能源（新能源）

Castles in the sky?

空中樓閣?

An innovative approach to making electricity from the wind

一種利用風能發(fā)電的創(chuàng)新方法

THE WIND BLOWS more strongly at higher altitudes. That is why wind turbines have grown ever taller. The blade tips of today’s biggest now reach up a dizzying 260 metres, the height of the Transamerica building in San Francisco. Many dream of capturing stronger winds even higher up than that, but building taller turbine masts and constructing blades able to withstand the terrifying stresses involved in high-altitude wind gathering are costly. A number of firms are therefore developing a different and, they hope, ultimately cheaper approach to generating electricity at great heights. Their idea is to skip the mast altogether. Instead they propose to fly kites.

越高，風吹得越猛。這就是風力渦輪機（架設）越來越高的原因。如今，這座最大的摩天大樓的刀尖高達令人目眩的260米，相當于舊金山泛美航空公司大樓的高度。許多人夢想捕捉比這更高的強風，但建造更高的渦輪機桅桿和建造能夠承受高空強風收集所帶來的可怕壓力的葉片的成本是昂貴的。因此，許多公司正在開發(fā)一種不同的方法，他們希望最終能以更便宜的價格在高海拔地區(qū)發(fā)電。他們的想法是完全跳過桅桿。因此，他們提議放風箏。

詞匯

Turbine/渦輪機

Blade/葉片；刀片

Transamerica building /泛美建筑; 泛美大廈

Mast/桅桿；柱

The kite developed by SkySails, a German firm, is a rectangular parachute-like structure attached to an 800-metre-long tether. This tether starts off coiled around a horizontal drum that is mounted on an axle which is anchored at each end in the shipping container in which the system’s generator is housed.

由德國SkySails公司開發(fā)的“風箏”是一個長方形的降落傘狀結構，連接在800米長的纜繩上。這條纜繩開始纏繞在一個水平的滾筒上，這個滾筒安裝在一個軸上，軸的兩端被錨定在裝有系統(tǒng)發(fā)電機的集裝箱內。

詞匯

Parachute/降落傘

Tether/范圍；系鏈；拴繩

Coiled/?盤繞的；卷成圈的

Axle/車軸；[車輛] 輪軸

SkySails’ kite is launched, like a recreational kite, into the wind at ground level. Then, as the kite is pulled up by the wind while being manipulated to travel in a series of figures-of-eight in order to achieve a constant, optimal speed, the tether uncoils, spinning the drum. That powers a generator. Once the tether is fully extended, the kite is angled to catch less wind, reeled partway back in, and allowed to reel out again. In-reeling, according to SkySails’ boss, Stephan Wrage, consumes only 4% of the energy the kite generates on its way out, so the process is pretty efficient.

SkySails的風箏像休閑風箏一樣，在地面迎風放飛。然后，當風箏被風拉起時，為了達到一個恒定的、最佳的速度，風箏被操縱成一系列的8字形，繩子就會解開，使鼓旋轉。為發(fā)電機提供動力。一旦纜繩完全伸展，風箏就會成一定角度，以減少風的撕扯，然后在達到一定程度后卷回去，再放出去。據(jù)SkySails的老板Stephan Wrage說，收放風箏只消耗了風箏在在工作時產生的能量的4%，所以這個過程相當有效率。

詞匯

Recreational/娛樂的，消遣的；休養(yǎng)的

?

Let’s go fly a kite

一起去放風箏吧

The SkySails Power system, as it is called, goes on sale next year. A single unit will produce 200 kilowatts—enough to run about 100 homes. It will, Mr Wrage says, cost about €300,000 ($340,000). At $1,700 a kilowatt, that is half the cost of a conventional turbine of equivalent capacity, and is comparable with the cost per kilowatt of industrial-scale turbines that have outputs measured in megawatts. Nor is SkySails alone in designing a system that works with a simple, wind-launched kite of this type. Kitepower, a competitor in the Netherlands, has come up with a similar arrangement, albeit somewhat smaller, which it, too, expects to be on sale next year. Other firms, however, are working on kites that are launched actively from the ground, rather than relying on winds near the surface for their initial lift.

這款名為SkySails的電力系統(tǒng)將于明年上市。一個單一的單元將產生200千瓦的能量——足夠運行大約100個家庭。Wrage先生說，這將花費30萬歐元(34萬美元)。每千瓦1,700美元的成本是同等容量的傳統(tǒng)渦輪機成本的一半，與以兆瓦為單位輸出功率的工業(yè)規(guī)模渦輪機的每千瓦成本相當。SkySails公司并不是唯一設計這種簡單的風動風箏系統(tǒng)的公司。荷蘭的競爭對手Kitepower也提出了類似的方案，盡管規(guī)模較小，但預計明年也會上市。然而，其他公司正在研制從地面自主發(fā)射的風箏，而不是依靠地面附近的風來獲取最初的升力。

詞匯

Conventional/傳統(tǒng)的；常見的；

albeit/雖然，盡管

?

One such is TwingTec, a Swiss firm. Its prototype rises dronelike into the air, lifted by electrically driven propellers at the end of its wings (which have a combined span of three metres). The kite then stays aloft until its sensors indicate that the wind has died down, after which it lands itself automatically on a truck-top pad. TwingTec is now building a bigger version, with a wingspan of 5.5 metres, that will begin producing power for BKW Energie, a Swiss utility, in October.

上述的公司，其中之一是瑞士的TwingTec公司。它的原型機像無人機一樣升到空中，由機翼末端的電動螺旋槳托起(機翼的總跨度為3米)。然后，風箏就會一直保持在空中，直到它的傳感器顯示風力已經(jīng)減弱，然后它就會自動降落在一個卡車頂部的墊子上。TwingTec現(xiàn)在正在建造一個更大的版本，翼展5.5米，將于10月開始為瑞士電力公司BKW Energie發(fā)電。

詞匯

Prototype/原型；標準，模范

Aloft/在空中；在高處；在上面

Wingspan/翼展；翼幅

?

Another system with active launch is that designed by Ampyx Power, a Dutch company. Its prototypes, which also have a wingspan of 5.5 metres, are propelled into the air by catapult—though, like TwingTec’s, they also have propellers to allow a controlled descent and landing once a tour of duty is over.

另一個自主發(fā)射的系統(tǒng)是由荷蘭Ampyx Power公司設計的。它的原型機也有5.5米的翼展，通過彈射器被推進到空中——不過，和TwingTec的一樣，它們也有螺旋槳，可以在任務結束后控制降落。

詞匯

Propel/推進；驅使

Catapult/彈射器

?

These current versions, though, are just the beginning. The firm hopes, later this year, to fly an arrangement with two fuselages and a wingspan of 12 metres. And even that is but a stepping stone. The target is a wingspan of 36 metres. This version, scheduled for 2024, will have an output (2.36 megawatts) and a price (€2.4m) about the same as those of a standard turbine in a wind farm.

不過，目前的這些版本僅僅是個開始。該公司希望，在今年晚些時候，能有兩架機身和12米翼展的設計成果。即便如此，這也只是一塊墊腳石。公司目標是36米的翼展。這一版本計劃于2024年投產，其發(fā)電量(2.36兆瓦)和價格(240萬歐元)將與風力發(fā)電廠的標準渦輪機大致相同。

詞匯

Fuselage/機身

?

Nor is it absolutely necessary that the electricity generation is done on the ground. Makani, a firm recently absorbed by Alphabet, Google’s parent company, has a different approach. It is lifting the generators into the sky, on board a pilotless aircraft with a wingspan of 26 metres. This craft has eight rotors, which act as propellers for take-off and landing. Once at operating altitude, however, they become miniature turbines. The electricity they generate (600 kilowatts at full capacity) is sent to the ground through a power line encased in a tether nearly half a kilometre long. Makani’s prototype has been tested in Hawaii and, later this year, a further series of tests from an oil platform off the coast of Norway are planned.

也并非必須在地面上發(fā)電。最近被谷歌母公司Alphabet收購的Makani公司則采取了不同的策略。它在一架翼展26米的無人駕駛飛機上把發(fā)電機抬到空中。這艘飛船有八個旋翼，作為起飛和降落的螺旋槳。然而，一旦到了工作高度，它們就變成了微型渦輪機。它們所產生的電力(600千瓦)通過一條近半公里長的纜繩包裹的電力線輸送到地面。Makani的原型機已經(jīng)在夏威夷進行了測試，今年晚些時候，還計劃在挪威海岸的一個石油平臺上進行進一步的測試。

詞匯

miniature /微型的，小規(guī)模的

encased/包裝的；被包住的

?

Up to the highest height

勇攀高峰

Whether power-generation from high-altitude winds actually can compete with existing turbines remains to be seen. The potential is certainly there. Airborne Wind Europe, an industry group based in Brussels, calculates that the wind blows fast enough at heights of around 500 metres for this form of energy production to work almost anywhere in Europe. Lower down, however, the strongest winds are often found in coastal areas. These are places where population densities are frequently high and land for onshore wind farms is thus expensive, while building those farms offshore increases the awkwardness of construction and maintenance.

高空風力發(fā)電是否能與現(xiàn)有的渦輪機競爭還有待觀察。潛力當然存在?？偛课挥诓剪斎麪柕囊粋€工業(yè)組織——Airborne Wind Europe (airwind Europe)計算出，風速在500米左右的高空足夠快，這種形式的能源生產在歐洲幾乎任何地方都能滿足需求。然而，在較低的地方，最強的風通常出現(xiàn)在沿海地區(qū)。在這些地方，人口密度往往很高，陸上風力發(fā)電場用地成本高昂，而在海上建設這些風力發(fā)電場，增加了建設和維護的難度。

詞匯

Airborne/空運的；空氣傳播的；風媒的

?

The mechanics of kite-flying, however, are more stressful than those of a wind turbine revolving smoothly and regularly. Flying tight figures-of-eight in gusty winds while pulling on a tether requires a robustness of structure and a precision of control that go beyond those involved in conventional aeronautics.

然而，放風箏的力學比風力渦輪機平穩(wěn)而有規(guī)律地旋轉的力學有更高的要求。在疾風中飛行時拉緊纜繩需要堅固的結構和精確的控制，這是傳統(tǒng)航空學所不能達到的。

詞匯

Robustness/穩(wěn)健性；健壯性

?

And if, despite all precautions, a tether were to snap, measures would need to be in place to bring both it and the kite once attached to it safely back to earth. Moreover, air-traffic-control authorities will doubtless have something to say if their airspace seems likely to be invaded by fleets of giant kites.

盡管采取了所有的預防措施，但如果繩子斷了，那么就需要采取適當?shù)拇胧?，將繩子和風箏安全帶回地表。此外，如果空中交通管制當局的領空似乎可能受到巨型風箏群的侵擾，他們無疑會吐槽。

?

Regardless of all this, high-altitude wind generation is an intriguing idea. In a world searching hard for alternatives to fossil fuels, it seems a promising option. The next few years should show whether or not that promise can be realised.

盡管如此，高空風力發(fā)電仍然是一個有趣的想法。在一個努力尋找化石燃料替代品的世界里，這似乎是一個很有前景的選項。未來幾年應該會證明這一承諾能否實現(xiàn)。

詞匯

Intriguing/有趣的；迷人的