Saudi Arabia of Renewable Energy' Off Scotland's
Jun 23, 2007 - The Scotsman
It has been described as the "greatest
untapped source of energy Scotland has ever had",
capable of generating enough electricity for every
home and business in the country several times over.
But while the Pentland Firth has been
too deep and too dangerous to exploit, the race
is now on to develop machines that will harness
this "underwater hurricane" and fundamentally change
Not only could it provide endless
supplies of electricity for Scotland and beyond,
but spare energy could be used to convert rubbish
into environmentally friendly biofuel for cars,
trains and airplanes, slashing greenhouse gas emissions
and ridding the country of landfill sites.
In August, the world's largest tidal-current
generator will be installed on Northern Ireland's
Strangford Lough and, next year, ScottishPower will
start testing an underwater turbine in the Pentland
ScottishPower believes its system
could generate up to a gigawatt (GW) of electricity
- equivalent to all of Scotland's wind farms put
together, or the power produced by the Hunterston
B nuclear power station.
But Professor Stephen Salter, who
wrote an energy review for the SNP extolling the
potential of the Pentland Firth, believes the actual
amount of energy could be as high as ten to 20GW.
He was turned down by the previous Scottish Executive
for funding to investigate the potential of installing
a tidal machine at depths previously considered
out of reach, but believes the SNP government could
be more receptive.
He said: "If we could do this, we
could get twice the electricity Scotland uses at
peak demand - it's absolutely enormous. The Pentland
Firth is the Saudi Arabia of marine energy. But,
if you are in London, energy from the Pentland Firth
is a long way away and there's no cable to get it
to your voters."
Prof Salter, of Edinburgh University,
has developed a form of cylindrical turbine which
he believes would be able to go deeper than ever
before, where the Pentland Firth's most powerful
currents are found.
The water in the fastest- moving channels
is about 70 metres deep. His machines operate down
to 50m, while seabed-based turbines could be used
in the bottom 20m.
The Firth would generate energy in
four regular tidal pulses a day, often generating
large amounts of power in the middle of the night.
Fuel cells or large industrial batteries could be
used to store spare electricity, but Prof Salter
said it could be used for a process which can turn
waste into gas or liquid fuel.
Martin Wright, managing director of
Marine Current Technologies, said the Pentland Firth
was the "Mount Everest" for the industry. He added:
"There's no doubt it is a stupendously energetic
area and the technology will have to be appropriate.
"The big prize is the very fast-moving
water in 60m to 70m of water. You are putting units
in the equivalent of an underwater hurricane there.
"It's all a question of will. I think
we could have done this in half the time if the
only challenges were technical."
What was needed, Mr Wright said, was
a strong statement of commitment from the Executive
to developing at least half a GW of energy from
the Firth, which would attract major global engineering
Duncan McLaren, of Friends of the
Earth Scotland, backed the potential of the Firth,
but cautioned against fast-tracking energy schemes
without assessing their environmental impact or
Grasping the Thistle, a book co-authored
by Mike Russell, now Scotland's environment minister,
hailed the Pentland Firth as "the greatest untapped
source of energy Scotland has ever had". Asked how
seriously the Scottish Executive viewed the potential
of the Pentland Firth, Jim Mather, the energy minister,
said its strategy "will have renewable energy at
Questions of power and the Pentland
How powerful is the Pentland Firth?
The flow of water from the Atlantic
to the North Sea and back again can reach speeds
of up to 12 knots.
About 2.5 million cubic metres of
water - 1,000 Olympic pools - will pass through
a line drawn across the Firth every second at peak
times. According to Professor Stephen Salter, this
could generate up to 10 to 20 gigawatts of power.
Hunterston and Torness nuclear power stations can
produce up to 2.5GW.
How can we harness this energy?
ScottishPower and Bristol-based firm
Marine Current Technology (MCT) have developed underwater
turbines which work in a similar way to wind turbines.
Prof Salter has designed a spinning cylindrical
turbine which he believes will be able to capture
the energy of the Pentland Firth. Seabed-based turbines
could be used with his system.
Where would the power go?
Bigger cables than currently exist
would be needed to take power down the east coast
to Aberdeen, Scotland's central belt, northern England
and possibly London.
The capacity of proposed upgraded
Beauly to Denny power line, currently being considered
by a public inquiry, will already be used by wind
farms in the pipeline.
How could we use the excess power?
Electricity can be stored in large
industrial batteries or used to split water, H2O,
into hydrogen and oxygen. Hydrogen can be used in
fuel cells to power vehicles or turned back into
electricity when needed.
It could be used to pump upwards into
hydro-electric reservoirs, which can provide electricity
at short notice to cope with sudden peaks in demand.
A cryogenic process can turn almost
any waste into gas or "super- clean diesel" for
vehicles and aircraft. (c) 2007 Scotsman, The. Provided
by ProQuest Information and Learning. All rights