Mark Latham
Deputy Business Editor
New ways to slash the costs of offshore wind based on a two-year programme
of research by the Glasgow-based Offshore Renewable Energy Catapult (OREC)
are set to be unveiled in a report to be published later this month.
The report, which makes use of research data obtained from OREC’s testing
facility at Blyth, aims to identify the ways to jump-start the stalled
maritime wind sector, by cutting costs by a third, to £100 per megawatt
hour (MW/h).
While this would still be more than the £85 per MW/h average cost of
land-based equivalents, it would make the investment return for offshore
developments broadly similar to onshore given the fact that windier
conditions at sea make offshore turbines 50 per cent more efficient.
The offshore sector’s high costs have led to a number of promising
potential projects around UK being shelved in recent years, including the
planned £5.4 billion 300-turbine Argyll Array off the coast of Tiree,
abandoned as financially unviable by Scottish Power in 2013 after four
years of planning.
Stephen Wyatt, OREC’s strategy director, told the Sunday Herald that the
forthcoming study will “identify the blocks the industry is facing as it
aims to reduce capital costs by almost 50 per cent by 2020.”
Wyatt said he was hopeful that improvements in technology, growth in the
industry’s supply chain, reductions in the cost of finance and the
economies of scale associated with large developments would help the sector
achieve its government imposed cost reduction target over the next five years.
One of the main measures to be examined in the report will be increasing
the size of offshore turbine blades from a current average diameter of 49m
to as much as 100m. Such an increase could more than double the output from
each turbine from 3MW to 8MW.
Wyatt also believes that sizeable cost reductions can be achieved by
designing new types of foundations and substructures for offshore wind
turbines. Reducing the amount of steel used in the construction of subsea
jackets by reducing the number of cross beams could also deliver cost savings.
Another more radical solution to reducing costs, which has been trialled at
a number of test sites in the UK, the US, Portugal, Norway and France, is
to get rid of fixed foundations completely by using floating turbines which
are either completely free floating or tethered to the seabed using mooring
lines and stabilised using ballast. Loosely anchored semi-submersible
platforms as well as tension-leg platforms are other low-cost alternatives
being examined.
The high cost of pile-driving turbine foundations into the seabed has been
blamed for the cancellation of a number of proposed high-profile projects
including, last year, the Celtic Array off the north coast of Wales.
The project’s backers blamed the cost of laying foundations in challenging
ground conditions but the cancellation of the project also coincided with
the introduction of a less generous subsidy regime.
If the development of floating subsea structures is successful it would not
only slash the costs of building wind farms in deep water locations but
also allow the construction of offshore wind farms in areas of the sea
where conventional monopole or tripod foundations cannot be installed. It
would also allow the building of wind farms in deeper seas where fixed
foundations are not practicable.
The report will also examine how changes to electrical infrastructure could
reduce transmission costs by up to 30 per cent. Among the possibilities
being examined are moving from AC to DC for medium and high voltage
transmission, which could lead to less electricity being lost and allow
transmission systems to better cope with strong wind gusts.
Early next year will see a final decision being taken by Scottish and
Southern Energy on whether to press ahead with plans to build the
140-turbine Beatrice offshore wind farm, some 14 miles off the coast of
Caithness. SSE said in November that it would only give the go-ahead to the
project if it “provides the return on capital investment required to be
compatible with the risks involved”.
Last month Benj Sykes, the manager for DONG Energy’s UK wind power
business, told a conference in Aberdeen on offshore wind organised by
industry body Scottish Renewables, that cost reduction was key to growing
the industry. “If we get costs down quickly then the scale of deployment
will increase and if we do not it will slow,” he said.
Linda Holt of the Scotland Against Spin lobby group, which campaigns for
the reform of what it calls the Scottish Government’s “unsustainable” wind
energy policy, said that the group was in favour of any report which
identifies savings for the offshore sector as offshore generation in
Scotland has not so far shown itself to be economically feasible.
Apart from a small number of test turbines on the east coast only one major
offshore wind farm has so far been installed in Scottish waters: the 180 MW
Robin Rigg farm in the Solway Firth. By contrast, around 20 offshore wind
farms have been built around the English and Welsh coasts in recent years.
“Unfortunately, the huge amount of public money that has been made
available to the sector through subsidies has stifled innovation and
research,” Holt said
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