Wave Power Stations
Monday, 20 November, 2000, 11:40 GMT
From the BBC ©
As
the climate change conference continues in The Hague, it
is perhaps fitting that the world's first commercial
wave power station is going into action in Scotland.
The power station, on the island of
Islay, is the product of years of research into how to
effectively harvest energy from the world's oceans.
The UK was one of the world's leaders
in developing wave power until a series of setbacks
coupled with a lack of funding scuppered promising
projects following initial enthusiasm in the late 1970s.
But supporters of the wave power
project believe that with climate change in the
headlines, the timing could not be better.
How it works
The Islay wave power generator was
designed and built by Wavegen and researchers from
Queen's University in Belfast and has financial backing
from the European Union.
Known as Limpet 500 (Land Installed
Marine Powered Energy Transformer), it will feed 500
kilowatts of electricity into the island's grid.
Limpet was born out of a 10-year
research project on the island where the team had built
a demonstration plant capable of generating 75 Kilowatts
of electricity.
The power generator consists of two
basic elements:
-
A wave energy collector
- A generator to turn this into
electricity
The energy collector comprises a
sloping reinforced shell built into the rock face on
the shoreline with an inlet big enough to allow
seawater to freely enter and leave a central chamber.
As waves enter the shell chamber,
the level of water rises, compressing the air in the
top of the chamber.
This air is then forced through a
"blowhole" and into the "Wells
Turbine", designed by Professor Alan Wells of
Queen's University.
The turbine has been designed to
continue turning the same way irrespective of the
direction of the airflow.
As the water inside the chamber
recedes as the waves outside draw back, the air is
sucked back under pressure into the chamber, keeping
the turbine moving.
This constant stream of air in both
directions, created by the oscillating water column,
produces enough movement in the turbine to drive a
generator which converts the energy into electricity.
But is it viable?
Wavegen says that there could be
sufficient recoverable wave power around the UK to
generate enough power to exceed domestic electricity
demands.
Furthermore, renewable energy
supporters say some research suggests that less than
0.1% of the renewable energy within the world's oceans
could supply more than five times the global demand
for energy - if it could be economically harvested.
That would probably involve
large-scale wave plants in near-shore or off-shore
environments, a technology still being developed.
However, large-scale on-shore wave
power generating stations could face similar problems
to those encountered by some windfarm projects, where
opposition has focused on the aesthetic and noise
impact of the machinery on the environment.
Wave power supporters say that the
answer lies not in huge plants but in a combination of
on-shore generation and near-shore generation (using a
different technology) focused on meeting local or
regional needs.
On-shore or near-shore plants, they
argue, could also be designed as part of harbor walls
or water-breaks, performing a dual role for a
community.
