# Wave P0wer in britain

Extracts from this document...

Introduction

Can Britain be totally dependent on wave energy in the future?

In this country there has been a growing importance in renewable energy there have been many conventions and meetings between politicians discussing about this topic. I will look at if Britain will be able to provide renewable energy from wave power for the whole country. Already Britain uses 358bn kWh but in the future that is set to increase to roughly 381bn kWh and out of the 358bnkWh only 15bn kWh is provided by renewable energy. I will look at the possibility of Britain being supplied 400bn kWh purely by wave energy. The advantage Britain has is that it is an island thus is surrounded by water and can easily set up ‘wave farms’.

There is plenty of energy stored in waves this is due to the conversion of wind energy in to waves. The waves are formed by wind; on a perfectly calm sea, the wind has practically no grip. As it slides over the water surface film, it makes it move. As the water moves, it forms small ripples. Ironically, these ripples do not travel exactly in the direction of the wind but as two sets of parallel ripples, at angles 70-80º to the wind direction. The wind that passes over the sea exerts a tangential stress on the water’s surface which in the end creates the large waves as the waves get only bigger and bigger.

Middle

Time

Date

Air temp

(°C)

Dew point

(°C)

Pressure

(hPa)

Wind speed

(kt)

Wind dir

Sea temp

(°C)

Wave height

(m)

09:00

27/09/07

14.4

8.0

1025.8

4.1

E

16.6

2.0

10:00

26/09/07

14.9

8.8

1030.6

8.0

NE

16.5

3.4

Looking at the Moored buoys at K2 and K1 they were giving readings at 3.4m at a high tide and 2.0 at a low tide. Using these figures we can do calculations.

When the wave height is 3.4m:

G=9.8

Therefore T= 1.476

When the height is 2m the wave period is:

Therefore T= 1.132

Using these figures we can put it into the earlier equation

Therefore P= 663015 KW

Using T = 1.132

P= 175955 KW

We must look at when we got high tides and low tides as this way we can accurately work out how much energy can be obtained during the day. Roughly the tides are split evenly so we can assume twelve hours for a high tide and twelve hours for a low tide. So when there is a low tide only 17.3KW is produced roughly per wave and when there is a high tide 65.1KW per wave is generated. I have obtained figures from the met office using the MAWS system indicating the time so how long it takes waves pass the certain point and the average time taken is 7.674419s so there is roughly 8 waves per minute this is equal to 470 waves per hour. Using this we can than work out that in half a day there is 5640 waves. So we can use this to work how much energy can be obtained:

High Tide:

5640*663015 = 3739405433KW

Low Tide:

5640*175955= 992385137KW

## So in a day 4.

Conclusion

( http://www.rise.org.au/info/Tech/wave/index.html )

The potential energy in waves can be found using the formulae P.E=mgh. First we need to work out the mass of the wave. This is done by working out the volume of the wave and then multiplying it by the density of water.

If the height of the wave is 2m and the base of the wave is 2m and the width of the wave is 5 metres then we get a volume of 10m3 this means we have a total mass of 10300kg as it is 1.03 x 103 Kgm-3.Now we can work out the potential energy in the waves. In the TAPCHAN system the waves, the waves go up 5m and the gravitational pull is 9.8 ms-2 so now we can work it out.

P.E= 10300 x 5 x 9.8

P.E= 403760J

Now we have to assume that this all happens in 5 seconds as then we are able to convert the joules into watts and from the conversion we get 80.75 kW. However we get the same problem with that a Kaplan Turbine is not a hundred percent efficient, it is around 80% efficient which means that only 64.6 kW is produced per wave. Which means in a day 558144 kW is produced. Which is converted to 23256 kWhr. This still isn’t sufficient enough energy for Britain which means that another method has to be discovered. Another method of exploiting the potential energy is with Wave Dragon where it is done off shore and does exactly the same thing but the potential is greater as waves further out at sea have a higher amplitude.

This student written piece of work is one of many that can be found in our GCSE Waves section.

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