Undersea turbines which produce electricity from the tides are set to become an important source of renewable energy for Britain. lt is still too early to predict the extent of the impact they may have , but all the signs are that they will play a significant in the future
A Operating on the same principle as wind turbines, the power in sea turbines comes from tidal currents which turn blades similar to ships' propellers, but, unlike wind, the tides are predictable and the power input is constant. The technology raises the prospect of Britain becoming self-sufficient in renewable energy and drastically reducing itscarbon dioxide emissions. If tide, wind and wave power are all developed. Britain would be able to close gas, coal and nuclear power plants and export renewable power to other parts of Europe. Unlike wind power, which Britain originally developed and then abandoned for 20 years allowing the Dutch to make it a major industry, undersea turbines could become a big export earner to island nations such as Japan and New Zealand.
B Tidal sites have already been identified that will produce one sixth or more of the UK's power - and at prices competitive with modem gas turbines and undercutting those of the already ailing nuclear industry.One site alone, the Pentland Firth, between Orkney and mainland Scotland, could produce 10% of the country's electricity with banks of turbines under the sea, and another at Alderney in the Channel Islands three times the 1,200 megawatts of Britain's largest and newest nuclear plant, Sizewell B, in Suffolk. Othep sites identified include the Bristol Channel and the west coast of Scotland, particularly the channel between Campbeltown and Northern Ireland.
C Work on designs for the new turbine blades and sites are well advanced at the University of Southampton'ssustainable energy research group. The first station is expected to be installed off Lynmouth in Devon shortly to test the technology in a venture jointly funded by the department of Trade and Industry and the European Union. AbuBakr Bahaj, in charge of the Southampton research, said: The prospects for energy from tidalcurrents are far better than from wind because the flows of water are predictable and constant. The technology for dealing with the hostile saline environment under the sea has been developed in the North Sea oil industry and much is already known about turbine blade design, because of wind power and ship propellers. There are a few technical difficulties, but I believe in the next five to ten years we will be installing commercial marine turbinefarms. Southampton has been awarded ￡215,000 over three years to develop the turbines and is working with Marine Current Turbines, a subsidiary of IT power, on the Lynmouth project. EU research has now identified 106potential sites for tidal power, 80% round the coasts of Britain. The best sites are between islands or around heavily indented coasts where there are strong tidalcurrents.
D A marine turbine blade needs to be only one third of the size of a wind generator to produce three times as much power. The blades will be about 20 metres indiameter, so around 30 metres of water is required.Unlike wind power, there are unlikely be environmental objections. Fish and other creatures are thought unlikely to be at risk from the relatively slow-turning blades. Eachturbine will be mounted on a tower which will connect to the national power supply grid via underwater cables. The towers will stick out of the water and be lit, to warn shipping, and also be designed to be lifted out of the water for maintenance and to clean seaweed from the blades.
E Dr Bahaj has done most work on the Alderney site, where there are powerful currents. The single underseaturbine farm would produce far more power than needed for the Channel Islands and most would be fed into the French Grid and be re-imported into Britain via the cable under the Channel.
F One technical difficulty is cavitation, where low pressure behind a turning blade causes air bubbles. These can cause vibration and damage the blades of the turbines. Dr Bahaj said: ‘We have to test a number of blade types to avoid this happening or at least make sure it does not damage the turbines or reduce performance.Another slight concern is submerged debris floating into the blades. So far we do not know how much of a problem it might be. We will have to make the turbines robustbecause the sea is a hostile environment, but all the signs that we can do it are good.'
關鍵詞: first test site
定位原文: C 段第 2 句“The first station is…”第 一個潮汐發電站預計很快將在德文郡的林茅斯海岸建立，用來檢測貿易與工業部和歐盟的一個合資項目研發的技術。
解題思路: 題干中的 first test 兩個詞都直接對應這句話中的 first...test; 而題干中的 site 對應原文的 Lynmouth in Devon, 表示測試站的地點。
關鍵詞: back into Britain
定位原文: E 段第 2 句“The single undersea turbine farm…”
解題思路: 僅僅這一個水下渦輪機群的發電量就遠比海峽群島所需要的電量還要多，其中大部分電量將運輸到法國電網，然后通過水下電纜重新進入英國。 題干中的 back into Britain 對應原文中的...be re-imported into Britain via the…
關鍵詞：previous, alternative source of energy
定位原文：A 段最后一句“Unlike wind power which Britain…” 與之前開發風能有所不同，風能由英國首先開發，而后卻擱置了 20 年，最后由荷蘭將其發展成一個主要產業，這次通過向日本與新西蘭這樣的島國出口水下渦輪機，英國將賺取巨額外匯。
解題思路: 題干中的previous對應這句話中的Unlike...0riginany, 為了突出這次潮汐發電的前景，這句話提到了之前英國對風能進行嘗試開發，但卻半途而廢，被荷蘭發展壯大。
關鍵詞：technology, another industry
定位原文：C 段第 4 句“The technology for dealing with…” 應對海底惡劣鹽漬環境的技術已經在北海油田工業中得以研發，而且人們對渦輪機葉片的設計已經有了了解。
解題思路：題目中的 another industry 對應這句話中的 the North Sea oil industry，屬于同義表達。
Question 18-Question 22
答案: A, D, E, F,J (in any order)
關鍵詞：claims about tidal power are made by the writer
解題思路: 選項 A(A 段第 1 句)題干中 more reliable source of energy(更可靠的能源)對應這句話中的...are predictable and the power input is constant, 表明潮汐能源具備風能所沒有的兩個優點：可預測的，恒定的;選項 B，過于絕 對，不選;選項 C，文中完全未提及;選項 D(A 段第 2 句)二氧化碳的排放量下降了，自然也減少了空氣污染;選項 E(A 段第 3 句)題干中的 contribute to the closure of many existing power stations 對應文中 的… dose gas, coal and nuclear power plants…;選項 F(A 段最后一句)，題干中的 national income 對應原文中的 earner (意為 a business or activity which makes a profit);選項 G、 H、I，文中完全未提及;選項 J(C 段倒數第二句)題干中 best produced in the vicinity of coastlines 對應這句話中的 The best sites are between...。
定位原文：D 段最后一句“..and also be designed…seaweed from the blades.”
解題思路：空格中的詞應該和定位詞 seaweed 構成并列關系，且出現在 and 之前，同時可預測詞性為名詞。此外，因為題干中的 raised 可同義替換成原文 lifted, 故符合要求的只有 maintenance, 意思為：整個機塔可以露出水面，以便維護葉片以及清理其中的海藻。
關鍵詞：due to, sea life not in danger, blades
定位原文：D 段第 4 句“Fish and other creatures are…”
解題思路：空格前有 due to，可預測需要填表示原因的詞。再進一步分析，空格前是副詞，因而空格要填的是形容詞。題干中 sea life not in danger 對應原文 creatures unlikely to be at risk(海洋生物不會面臨危險)，原因是葉片轉速相對較低，所以 slow-turning 為備選。同時，題干中 comparatively 可同義替換原文中的 relatively，所以備選答案被驗證，此空應該填 slow-turning。
關鍵詞：result from, behind blades
定位原文：F 段第 1 句“One technical difficulty is…”
解題思路：空格里應該填名詞，表原因，并且是出現在定 位詞 behind, blades 之前，包含定位詞的這句話中可能是答案的有兩個名詞：cavitation，low pressure。題干中的 result from 對應原文中的 cause,而能夠形成緊密因果關系的是 low pressure, 之前的 cavitation 是這種技術難題的名稱。整個題干的意思為：葉片后方由于氣壓低而產生氣泡。這種技術難題被稱做空化。所以 25 題答案為 low pressure，26 題答案為 cavitation。
定位原文：F 段第 1 句“One technical difficulty is…”
解題思路：參考 25 題分析。題干 known as 對應原文中...is...