APPENDIX 5: VISIT TO SCROBY SANDS OFFSHORE
WIND FARM—9 MAY 2008
The Members of the Committee that visited Scroby
Sands were Lord Freeman (Chairman), Lord James of Blackheath,
Lord Powell of Bayswater, Lord Walpole.
Scroby Sands is a wind farm owned and managed by
E.ON. It was opened in 2005 and is sited 2.5km off the coast of
Caister, near Great Yarmouth. It has a generating capacity of
60MW, supplying energy for 41,000 homes.
The Committee were met by Dave Rogers, UK Regional
Director of E.ON Climate and Renewables, Adrian Chatterton, Head
of Construction and John Beresford, Asset Leader for the wind
farm.
Dave Rogers gave the Committee an overview of E.ON
Climate and Renewables, a business within E.ON set up in 2007
to manage and develop E.ON's renewable energy portfolio. E.ON
has 1353MW of renewable generation installed in Europe and the
USA. 245MW of this is sited in the UK spread across 20 generation
sites. These sites include 2 offshore wind farms, 1 biomass plant
and 17 onshore wind farms. The Scroby Sands installation is the
largest of these. Currently under construction is a third offshore
wind farm in the Solway Firth. This wind farm, Robin Rigg, will
have a generating capacity of 180MW.
Adrian Chatterton then gave a presentation describing
the construction of the Scroby Sands site. The choice of the site
on the relatively shallow waters of Scroby Sands had benefits
and problems. The shallow waters mean that the 7.4km2
site is located away from shipping lanes. This was a problem during
construction because it required the use of suitably shallow draught
construction vessels and construction could not be carried out
a low tide. The Scroby Sands site does, however, benefit from
good port facilities at Great Yarmouth and Lowestoft.
The power generated from the wind farm is cabled
back to shore and connected at an existing substation to the distribution
network. This meant that the project bypassed any potential problems
with connection to the transmission grid.
During his presentation Mr. Chatterton identified
some of the constraints on developing this kind of wind farm.
There are the practical difficulties of matching the construction
plan to suitable weather and tidal conditions. More importantly
there are supply chain constraints. All energy generators will
be affected by rises in copper and steel prices but there are
particular supply chain problems for renewable energy. For example,
during the construction of Scroby Sands E.ON used turbine piles
made by two different manufacturers. These firms no longer exist
and Robin Rigg will use parts made by only one company. Similarly,
specialist vessels needed for offshore construction are in short
supply. The uncertainty created by these conditions can be seen
in the price for construction. Whilst Scroby Sands cost around
£1.2m per MW, future projects will cost at least £2.4m
per MW.
In order to stimulate the necessary industrial infrastructure
clear and stable policy signals are required from Government.
All three of the representatives welcomed the proposed re-banding
of the Renewables Obligation (RO) scheme to provide 1.5 RO Certificates
per MW for offshore wind and stated that without this change the
construction of offshore wind farms would not be possible.
John Beresford then gave a presentation discussing
some of the practicalities of keeping the wind farm operational.
The turbines can generate power with wind speeds as low as 4 m/s
and will generate at their full potential at speeds of 14-25 m/s.
Above this point the blades are turned from the wind to avoid
damage. For around 90% of the time the turbines will be generating
at an overall load factor of around 30%.
As with the construction of the wind farm, maintenance
is affected by weather conditions and lack of specialised vessels.
Maintenance is not possible for around 120 days a year due to
weather conditions and the two existing vessels suitable for large
scale maintenance work are frequently in demand for other projects.
This increases the cost of the running of the wind farm in comparison
to an onshore installation.
The Committee then took a boat out to the wind farm.
During discussions on the boat the current state of offshore farm
development was characterised as needing to evolve from a "cottage
industry" to a full industrial size. This move is apparent
in the difference in generating capacity of Scroby Sands (60MW)
and Robin Rigg (180MW). It was noted, however, that the gas-fired
power station in Great Yarmouth can generate around 400MW with
a higher load factor than wind farms. Another issue related to
this increase in scale was that the operation of Scroby Sands
has provided lessons in matters relating to offshore wind farms.
For example, some of the original gears in the Scroby Sands turbines
were found to be too fragile despite being tried and tested over
some years on onshore wind farms. The Robin Rigg site is now being
built with more hard wearing gear boxes.
The issue of planning was also discussed. Whilst
no specific planning problems were discussed in relation to the
Scroby Sands site, it was suggested that to facilitate the planning
system a target for renewable generation should be set for local
authorities (as exists for waste recycling) rather than simply
encouraging them to work towards a national target.
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