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The
Powerplants
The powerplants
were built in 1985 to demonstrate how to convert wave energy into
electrical energy. Two different principles where tested –
Oscillating Water Column and Tapered Channel. The first one was
built by Kv?rner Brug and the latter one was built by Norwave – a
company that no longer exist.
Oscillating Water
Column
 The Osillating Water Column powerplant was built
on the north side of the funnel leading into the reservoir –
on the island Toftestallen. If you wonder why the bridge (that
has almost completely collapsed) over the funnel was built, it
was to give access to the Oscillating Water Column powerplant.
Toftestallen is now connected to Kval?yni after the sea has
washed enormous amounts of rock into the reservoir between the
two islands.
In an
oscillating water column a part of the ocean surface is trapped
inside a chamber which is open to the sea below the water line.
When the internal water surface moves up and down in response to
incident waves outside the chamber, the air in the chamber is
pressed and sucked through a turbine due to the generated
overpressure and underpressure.
The OWC plant at
Toftestallen was a 17,5m tall steel cylinder on top of a 3,5m tall
concrete foundation. It was built partly into the rock surface. An
air turbine and a generator on the top of the cylinder produced 500
kW that were fed into the local electricity network.
Besides
producing electricity the OWC plant also produced an annoying loud
whizzling sound that was audible several km away – almost like a
foghorn.
The OWC plant
was operational for 3 years. In 1988 it was hit by a ?100 year
wave? and the whole construction was washed into the sea. As far as
I know no attempts were done to rescue it.
The only visible
remains of it is the concrete foundation and the recess in the rock
surface that is still present on the north side of the tapered
channel.
The Tapered
Channel
 The tapered channel is a horizontal
funnel which is wide towards the sea where the waves enter and
gradually narrows towards a reservoir at the other side. As
the waves pass through the funnel, water is lifted over the
channel wall and into the reservoir due to the shortage of
space which occur as the funnel gets narrower.
The tapered
channel power plant at Kval?yni was built where a natural cleft has
focused the waves in between the two islands. The cleft has been
modified and a concrete funnel has been built to make the waves
spill water into an artificial reservoir with surface 3 metres
above sea level. A low pressure water turbine and generator in a
turbine house (in the upper right corner of the picture) on the
eastern side of the island produced 350 kW that were fed into the
local electricity network.
While
operational it was a continous problem that the sea washed rocks
into the funnel and blocked it. It became standard procedure to
remove these rocks after a period of bad weather. There was a
tragic incident where a professional diver was killed while
drilling holes in a large rock that blocked the funnel. A previous
attempt on blasting the rock had not gone completely well and while
drilling more holes he accidentally set off the remaining dynamite
and killed himself.
I am not
completely sure if the tapered channel plant was abandoned after
this incident, but it seems like the funnel was completely
destroyed and the reservoir was filled with rocks during
winterstorms in 1989 and 1991.
Today you may
see the funnel filled with rocks, but even on calm days it may
produce occational spray of water on the inside – enough to make
you wet if you dare stand at the end. You may also hear a scary
swooshing sound as the sea builds up inside the funnel before
splashing out at the end. |