Wave energy has had a short but fascinating history, and faces an uncertain future. This paper examines the activities of various countries in research and development of wave energy programmes. The changes in the political fortunes of research teams have often been more extreme than the wave climates that they seek to harness.
The potential contribution to energy supplies from wave energy technology is considerable, but is the technology economically viable and politically acceptable? The current state of developments will be reviewed and the prospects from small scale schemes to large floating arrays will be discussed.
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Table 1 give some estimated resources for hydro, tidal and wave technologies and shows that the wave resource is of a similar magnitude to hydro. Large scale hydro schemes provide about a quarter of the World's total electricity supply, virtually all of Norway's electricity and more than 40% of the electricity used in developing countries. The technically usable World potential of large scale hydro is estimated to be over 2200GW, of which only about 25 % is currently exploited. There are no accurate estimates of the number or capacity of small hydro plants, but based on rainfall and the average land elevation, the potential for such plants may be of a similar scale to the large hydro resource. Each site might only produce a few kW to hundreds of kW but the number of possible sites is extremely large, and indeed may provide more appropriate facilities for local communities. The World tidal resource is difficult to estimate but here we use 200GW which is 10% of the total tidal flux. Notice the large proportion of the World resource available to the UK. The World wave resource is between 200 and 50(0~W mostly found in offshore locations. Wave energy converters fixed to the shoreline are likely to be the first to be fully developed and deployed, but waves are typically 2 to 3 times more powerful in deep offshore waters than at the shoreline. Floating off-shore devices could be deployed in arrays or farms of thousands of structures and so harvest enormous amounts of energy, which could be transmitted to shore via subsea cables.
]EtkY~,lt~,R.Ca~ Strong winds blowing for some time over a long stretch of water will generate large waves. Wave energy can be considered as a stored and concentrated form of solar energy since wind patterns mostly arise from solar radiation. Developments over the last 20 years have led to a number of concepts for