用于潮汐发电的海底涡轮机即将成为英国可再生能源的一项重要来源。现在预计它们将会带来多大的影响还为时过早，但是所有的迹象都表明它们将会扮演一个举足轻重的角色。

Undersea turbines which produce electricity from the tides are set to become an important source of renewable energy for Britain. It 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 role in the future

A 海底涡轮机的运作原理与风力涡轮机是同样的，它的动力来自潮汐水流，水流推动涡轮机的叶片就像轮船的推动器一样，但是，潮汐与风力不同的是，潮汐具有可预知性并且潮汐动力的输入是连续不断的。科技的发展提升了英国实现本国可再生能源自给自足同时大大减少二氧化碳排放量的前景。如果英国同时开发本国的潮汐能、风能和海浪能，那么它就有可能将本国的天然气、煤炭和核能发电厂全部关闭并且还能向欧洲其他地区输出可再生能源。英国起初开发了风能但放弃利用风能已经 20 多年，在此期间，荷兰却将其变为本国的一项支柱产业。海底涡轮机和风能不同，对于像日本和新西兰这样的岛国来说，它能够成为出口盈利的大赢家。

B 潮汐地区已被确定将会产生满足英国六分之一或者更多的动力需求，其在价格上亦能和现代燃气涡轮机相媲美又比麻烦不断地核能工业更加低廉。彭特兰湾（Pentland Firth）坐落于奥克尼群岛（Orkney）和苏格兰大陆之间，仅仅凭借这一个区域的数排海底涡轮机就能满足全国10%的用电量，而位于海峡群岛（the Channel Islands）的奥尔德尼岛（Alderney），此处利用潮汐产生的发电量可以达到赛兹韦尔 2 号站(Sizewell B)的 3 倍，赛兹韦尔 2 号站(Sizewell B)是位于萨福克郡（Suffolk），被誉为英国最大且最近建造的核能站，其发电量达到 1200 百万瓦特。其他被认定的潮汐区域包括布里斯托海峡（the Bristol Channel）和苏格兰西海岸地区，特别是地处坎贝尔敦（Campbeltown）和北爱尔兰岛之间的海峡。

AOperating 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 its carbon 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.

C 南安普顿大学的可持续能源研究小组致力于研发适合新型涡轮机叶片和区域的设备，并且取得了较大的进展。首个工作站将在不久后安装于德文郡（Devon）的林茅斯（Lynmouth），以检测由贸易和产业部联合欧盟共同投资研发的新技术。南安普顿大学研究项目的负责人AbuBakr Bahaj 说：“利用潮汐水流开发能源的前景要远远好于利用风能获取能源，这是因为水的流动是可以预知推测的并且是持续不断的。并且在发展北海石油工业时，我们已经获取了应对海底不利的盐化环境的技术；在利用风能和轮船推动器的过程中，我们也已经掌握了关于涡轮机叶片设计的众多知识。虽然我们仍然存在一些技术困难，但我相信在今后的五到十年里，我们将能够建造商业性质的海洋涡轮机基地。”三年以来，南安普顿大学获得了 215000英镑的经费用于研发涡轮机，并且与英国可再生能源公司IT Power 的附属机构海流涡轮机公司（Marine Current Turbines）共同合作进行林茅斯项目（the Lynmouth project）的研发。到目前为止欧盟科研组已经认定了106处作为开发潮汐动力的潜在地区，其中 80%的区域位于英国海岸附近。开发潮汐动力的最佳位置是在两岛之间或者是在严重凹陷进去的海岸周围，因为此处存在大型潮汐和巨浪水流。

D 海流涡轮机的叶片只需做成风力发电机叶片的三分之一大小，所产生的动力就会达到后者的三倍。叶片的直径大概是20米，因此水流就必须达到30米左右的高度。与风能不同的是，潮汐能的开发利用很少会受到环境方面的影响。鱼和其他生物不太可能冒险穿梭于这些旋转速度相对较慢的叶片之间。每一个涡轮机都将被放置于一个塔架之上，这些塔架将通过水底电缆和国家供电网相连。塔架上部会高出水面并且其上会点亮灯光以警示过往船只，塔架还被设计成可以升出水面的构造以便于维修护理和清理叶片上的海草。

BTidal sites have already been identified that will produce one sixth or more of the UK's power 一 and at prices competitive with modern 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. Other sites identified include the Bristol Channel and the west coast of Scotland, particularly the channel between Campbeltown and Northern Ireland.

E Bahaj教授的大部分研究工作是在奥尔德尼岛（Alderney）地区完成的，这个区域有强有力的水流。只此一个海底涡轮机基地就可以产生出远远超过海峡群岛（the Channel Islands）需求的动力，并且产生的大部分动力可以输往法国电网再通过海峡底部的电缆重新进入英国电网。

F 气穴现象的影响是众多技术难题之一，转动的叶片后面会出现低压从而产生气泡。这些气泡能造成一定的振动并且损害涡轮机的叶片。Bahaj教授解释道：“我们必须测试众多的叶片类型来避免这种情况的发生或者至少要确保不损害涡轮机或影响它的运作。另外令人有点忧虑的事情是沉入水中的碎片残骸可能会漂浮入叶片之中。但至今为止我们还不清楚这个问题可能会带来多大的困扰。所以我们必须将涡轮机建造的稳固耐用，因为海洋是一个充满危险的环境，但所有的迹象都表明我们可以成功完成这项工程。”

CWork on designs for the new turbine blades and sites are well advanced at the University of Southampton's sustainable 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 tidal currents 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 turbine farms.' 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 106 potential 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 tidal currents.

DA 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 in diameter, so around 30 metres of water is required. Unlike wind power, there are unlikely to be environmental objections. Fish and other creatures are thought unlikely to be at risk from the relatively slow-turning blades. Each turbine 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.

EDr Bahaj has done most work on the Alderney site, where there are powerful currents. The single undersea turbine farm would produce fan 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.

FOne 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 robust because the sea is a hostile environment, but all the signs that we can do it are good.'