Ok what else do we need to talk about maybe something

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OK. What else do we need to talk about? Maybe something on future risks, looking more at the long term, if populations continue to grow. Yeah. We ll need to do a bit of work there, I haven t got much information, have you? No. We ll need to look at some websites. Shouldn t take too long. OK. And I think we should end by talking about international implications. Maybe we could ask people in the audience. We ve got people from quite a lot of different places. That d be interesting, if we have time, yes. So now shall we ... c ar l a : r o b : c ar l a : Q27 r o b : c ar l a : r o b : Q28 c ar l a : r o b : c ar l a : r o b : c ar l a : Q29 r o b : c ar l a : Q30 r o b : SECTION 4 Producing enough energy to meet our needs has become a serious problem. Demand is rising rapidly, because of the world s increasing population and expanding industry. Burning fossil fuels, like gas, coal and oil, seriously damages the environment and they ll eventually run out. For a number of years now, scientists have been working out how we can derive energy from Q31 100
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renewable sources, such as the sun and wind, without causing pollution. Today I ll outline marine renewable energy - also called ocean energy - which harnesses the movement of the oceans. Marine renewable energy can be divided into three main categories: wave energy, tidal energy and ocean thermal energy conversion, and I ll say a few words about each one. First, wave energy. Numerous devices have been invented to harvest wave energy, with names such as Wave Dragon, the Penguin and Mighty Whale, and research is going on to try and come up with a really efficient method. This form of energy has plenty of potential, as the source is constant, and there s no danger of waves coming to a standstill. Electricity can be generated Q32 using onshore systems, using a reservoir, or offshore systems. But the problem with ocean waves is that they’ re erratic, with the wind making them travel in every direction. This adds to the difficulty of creating efficient technology: ideally all the waves would travel smoothly and regularly along the same straight line. Another drawback is that sand and other sediment on the ocean floor might be stopped from flowing normally, which can lead to environmental problems. Q34 Q33 The second category of marine energy that I ll mention is tidal energy. One major advantage of using the tide, rather than waves, as a source of energy is that it s predictable: we know Q35 the exact times of high and low tides for years to come. For tidal energy to be effective, the difference between high and low tides needs to be at least five metres, and this occurs naturally in only about forty places on Earth. But the right conditions can be created by constructing a tidal lagoon, an area of sea water separated from the sea. One current plan is to create a tidal lagoon on the coast of Wales. This will be an area of water within a bay at Swansea, sheltered by a U-shaped breakwater, or dam, built out from the coast. The breakwater will contain sixteen hydro turbines, and as the tide rises, water rushes through the breakwater, activating the turbines, which turn a
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  • Fall '19
  • The Passage, Alexander Henderson

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