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FOURTEEN years after the British government decided to invest in capturing
the energy of the waves, a gully on the island of Islay in the Inner Hebrides,
is the setting for Britain’s first small step in exploiting the motion of
the sea. A team of researchers from Queen’s University, Belfast, will install
a turbine in a ‘power station’ that is no bigger than a garden shed – the
generator will provide enough electricity to light just 360 living rooms.
This is a long way from the 2000-megawatt station envisaged when the Department
of Energy launched its pioneering programme for the development of wave
energy in April 1976.

Why is progress so slow? Trevor Whittaker, a reader in civil engineering
at Queen’s University and the person in charge of the Islay project, is
charitable. ‘It probably results from man’s fear of the awesome power of
the sea,’ he says. Other advocates of renewable energy blame the power and
influence of the nuclear and fossil fuel industries in getting their own
way, so much so that, in 1982, the government temporarily abandoned investment
in wave energy research altogether. One development over the past year,
however, offers renewed hope.

The government has quietly embarked on a new study of wave power, a
move that came as a complete surprise to advocates of renewable energy.
In October 1988, during the public inquiry into the construction of a nuclear
power station at Hinkley Point in Somerset, the government stated categorically
that it did ‘not intend to establish another review of wave power’. Just
five months later, in April 1989, Baroness Hooper, then a junior energy
minister, told the House of Lords that the government planned to do just
that.

Evidence from Norway that wave energy is economically viable, coupled
with persistent lobbying in Britain to re-evaluate its potential, helped
to bring about the change. What was particularly significant in Baroness
Hooper’s announcement was a reference to the potential of wave energy offshore.
She said: ‘I have asked that a study on wave energy including offshore technologies
should be made at an early stage.’ Advocates of renewable energy were taken
aback: nothing has changed in this area since the closure of the British
programme in 1982.

The decision to end funding for wave power projects followed a report
by the Energy Technology Support Unit, which oversees the government’s research
into renewable energy. The Department of Energy had told ETSU that it wanted
to invest only in renewable energy schemes that could generate electricity
for around 5 pence per kilowatt-hour, which was about the cost of power
from traditional sources. ETSU, in its report, Wave Energy ETSU R26, which
was not published until March 1985, decided that ‘there is only a low probability
of any design achieving a cost below 8 p/kWh in May 1982 money values’.
The Norwegian government, meanwhile, continued to fund the research and
development of wave energy and, by late 1985, two power stations on a cliff
near Bergen were generating electricity for between 4 and 5 p/kWh. By then,
ETSU’s 8 p/kWh had risen to around 10 p/kWh in real terms.

Chided by the experience and impressed with Whittaker’s proposal for
the Islay project, the government relented in July 1987 and provided Pounds
sterling 230,000 for the construction of the small power plant on Islay.
A few months later, in December 1987, following questions from members of
both houses of parliament, the House of Lords Select Committee on the European
Communities began an investigation of alternative energy sources. One witness
was Stephen Salter, professor of engineering design at the University of
Edinburgh and inventor of the ‘duck’, a wave power device that bobs up and
down in the sea. He gave evidence showing that the efficiency of his device,
heralded by advocates of renewable energy as one of the most promising inventions
for harnessing wave power, had been misrepresented during the government’s
reappraisal of wave energy in the early 1980s. His comments have since been
vindicated (This Week, 14 April).

The select committee report, published in June 1988, called for further
examination of wave power, a decision the government finally endorsed when,
nine months later, it commissioned the current study from ETSU. Tom Thorpe,
a member of the chief scientist’s group at ETSU, expects to complete the
study by August next year.

Proponents of wave energy welcome the review but they remain suspicious
of the government’s intentions. Only two months ago, the Department of Energy
became embroiled in a dispute with the renewable energy industry over its
decision to restrict the length of contracts for the supply of electricity
to eight years. This move would hamper the industry’s attempts to compete
for the contracts: many renewable energy schemes require a longer period
to recover the costs of establishing themselves (This Week, 31 March). The
department and the Treasury are now thought to be negotiating a method of
compensating the industry so that it can compete for the supply contracts.

One of the sceptical proponents of wave energy is David Evans, professor
of mathematics at the University of Bristol and inventor of the Bristol
Cylinder. This is a wave power device that rotates under the surface of
the water, driving hydraulic pumps as it rises and falls in the underspin
of the waves. In November last year, at an international conference on wave
energy devices organised by the British section of the International Solar
Energy Society, he asked ETSU representatives: ‘What are you going to discover
about offshore wave energy that you did not know in 1982?’ Evans says the
study will largely cover known facts: there is nothing new to learn.

Meanwhile on Islay, Whittaker prepares to generate electricity from
his device, Gully One, which he has developed from two ideas that originated
in Norway and in Japan. Norwegian engineers invented the Tapchan, from the
English words tapered channel. This is a concrete slope leading to a reservoir
three metres above sea level. The waves enter the channel and run uphill,
pushed forward by the waves behind and upwards by the tapering walls, into
the reservoir. From the reservoir, the water runs out through a standard
Kaplan turbine, back to the sea through a pipe. Japanese engineers devised
the Oscillating Water Column (OWC), which looks like a chimney standing
in the sea and is open at its base. As the waves rise in the sea outside,
the column of water inside the chimney also rises, forcing a pocket of air
up through a turbine. As the wave level falls, air is sucked back in from
the atmosphere, which spins the turbine again. A team of researchers at
Queen’s University, headed by Alan Wells, a professor of civil engineering,
now retired, invented the turbine for wave energy devices. The blades of
the Wells Turbine, as it is called, spin in the same direction irrespective
of the direction of the inflowing air. Whittaker has added a flywheel to
the turbine to smooth its output of electricity: during calm weather the
momentum of the wheel keeps the turbine spinning.

Calm weather has not so far been one of the team’s problems, however.
Waves have been so ferocious that Whittaker had to build an artificial barrier
across the entrance to the natural gully to protect the construction site.
If there are more projects, he plans to use what he terms ‘designer gullies’,
which will be made of concrete in a dry place, a few metres back from the
sea. When the work is finished, he will blast a gap in the cliff and take
the gully to the water.

While Whittaker awaits delivery of the turbine for Gulley One, whose
structure is now complete, he is recording the power of the sea by measuring
the flow of water and air pressure in the OWC. The power ranges from a peak
of 700 kilowatts per metre, for brief periods in very heavy seas, to less
than 36 kW/m, which researchers calculate is the average. The waves off
the west coast of Scotland contain 70 kW/m of power, which drops to 10 kW/m
in shallow water inshore where the waves break and lose energy as turbulence
and friction on the seabed. In the gully, where the narrowing sidewalls
squeeze the water into a climbing torrent, the power increases to between
20 and 30 kW/m. This is just as researchers predicted when they forecast
that power from the sea could be cheaper than that from traditional fuels.

Meanwhile Whittaker must cope with the practical problems of building
a pioneering power station. The roof of Gulley One’s OWC stands nearly 9
metres above mean water level and yet Atlantic rollers can climb half a
metre above it. The entire peninsula on which the power station is built
disappears under water in a storm. The project is then virtually inaccessible,
says Whittaker, but this does not matter as long as the waves are not destructive.
They were in Norway: the OWC at Bergen was ripped off the cliff face in
exceptional storms in December 1988. This caused the OWC’s owner, Kvaerner,
to abandon wave energy. But another Norwegian company, Norwave, continues
to market the Tapchan device.

Even Mehlum, Norwave’s managing director, is offering to provide Tapchan
power stations around the world for free. The only catch, according to Mehlum,
is that Norwave must own and operate the station until the company has earned
a profit. He says the first one will go to Tasmania, where he is currently
negotiating an agreement with the Hydro-Electric Commission to build a 1.5-megawatt
station on King Island in the Bass Strait. Mehlum estimates that the station
will generate electricity at a rate of 4 p/kWh, which is cheaper than power
from traditional power plants. He expects to make his profit within four
years. In Indonesia, he hopes to sell up to 400 power stations over the
next two decades.

So what is the cost of energy from the sea? Advocates of wave energy
claim that ETSU’s economists do not give enough credit to the major commercial
advantages of their schemes. Although the schemes are more expensive to
create than traditional ones, they are much cheaper to run, their fuel is
free and they survive longer, for 120 years or more compared with 25 to
30 years for a nuclear power station, for instance. The Severn Tidal Power
Group outlines the problems in its latest report, Energy Paper 57, which
was published in October last year. According to the group, electricity
generated by a tidal barrage that was designed to operate for only 60 years
would cost 6.1 p/kWh on the basis of official calculations. The trouble
is that even if the barrage were designed to last for 120 years, ETSU economists
would say that the electricity it generated would still cost about the same
amount, 6.01 p/kWh. Official calculations do not acknowledge the advantage
of having electricity flowing for an extra 60 years without the expense
of building a new power station.

Whittaker cannot see the logic of the system: ‘You can’t tell me that
if I pay for my house in 25 years, it will cost as much to knock the house
down and build a new one as it will to keep the old one for another 25 years.’
He condemns the power of accountants: ‘The strides that you make in engineering
are insignificant compared with the increase in costs that you get just
by doing the sums in a different way.’

These issues are outside the brief of Tom Thorpe, who is visiting the
major centres of wave energy research in Britain to draw up his report for
ETSU. He has already been to Edinburgh to see Salter’s Duck and to the National
Engineering Laboratory at East Kilbride that wants to build an OWC standing
on the seabed off the island of Lewis in the Outer Hebrides. He has seen
Coventry Polytechnic’s Clam, a device in which waves squeeze air between
compartments in a reinforced-rubber bag shaped like a lifebuoy.

Wave energy, and other forms of renewable energy, must be considered
as alternative methods of generating electricity following the government’s
decision to abandon plans for the construction of new nuclear power stations
in Britain for at least five years. But will it need another oil crisis,
war in the Middle East or Chernobyl accident before there is serious investment
in capturing the restless motion of the sea?

* * *

THE POTENTIAL OF TIDAL POWER . . . STILL ALL AT SEA

THE DEVELOPMENT of wave power may be too slow for advocates of renewable
energy but it is rapid compared with the progress in harnessing tidal power,
first exploited by the Romans.

In Britain, re-evaluation of the potential of tidal power began in 1925,
when the government first considered building a barrage across the River
Severn. This would trap an incoming high tide and then pass the water through
turbines to generate electricity, before letting it wash out to sea at low
tide. The potential of the scheme is enormous – the barrage could generate
8000 megawatts. The cost of the project, however, has proved overwhelming.
Last October, the Severn Tidal Power Group, the consortium of private companies
that wants to build the barrage with financial support from the government,
estimated the cost of the scheme to be Pounds sterling 8280 million. The
government is not interested.

As a result, advocates of tidal power in Britain have focused their
attention on a more modest proposal to build a barrage across the River
Mersey. The attraction of this scheme, which would generate 700 megawatts
and cost around Pounds sterling 880 million to build, is the interest of
private investors in financing the work. Peter Wood, the project’s development
manager, is raising support among local companies, from Littlewoods, the
firm that makes its money from popular gambling on football results, to
the Merseyside and North Wales Electricity Board, which is due to be privatised
later this year.

The backers of the Mersey barrage hope that their project will encourage
development of the bigger scheme at Severn, though some experts question
how much practical guidance it can provide. According to Reg Clare, chairman
of the Severn Tidal Power Group, tidal power projects are unique. Unlike
wave energy devices, which can be used in a broad range of sea conditions
and can be transferred from one site to another, tidal power projects must
be designed for a specific site. In Brittany in 1965, French engineers completed
a tidal barrage across the River Rance that was intended to be the forerunner
of a much bigger project, a 12,000-megawatt barrage in the Bay of Saint
Michel. But the French government got cold feet and decided instead to press
ahead with an energy programme based on nuclear power.

Despite the opportunities that exist around the world to exploit tidal
power, from the single 6400-megawatt scheme proposed for Canada’s Bay of
Fundy to the 500 potential sites in China that could generate 110 000 megawatts,
no major construction work is under way. According to Eric Wilson, former
professor of hydraulic engineering at the University of Salford and a leading
expert on tidal power, only one project is being seriously considered –
in the Tugursky Gulf on the Okhotsk Sea in Siberia. He says that this scheme
was approved because of the Chernobyl accident and the opposition to nuclear
power in the Soviet Union.

Wilson blames the shortsightedness of investors. A tidal power scheme
may be expensive to build, he says, but it is cheap to run: ‘After a time,
it is a gold mine.’

David Ross is a freelance writer who specialises in renewable energy.