Page 60 - European Energy Innovation - Spring 2017 publication

60 Spring 2017 European Energy Innovation
WIND ENERGY
have been important to disseminate
results of various national projects and
creating synergies across the national
borders.
BETTER, FASTER AND MORE
EFFICIENT
Together with its partners, ECN has
been developing innovations to make
offshore wind more reliable and more
efficient. Breakthroughs have been
achieved at several levels, from blade
and rotor innovations, through to
wind farm control, optimising wind
farms and more efficient operation
and maintenance processes. Some
examples are provided below:
WIND FARM CONTROL
A characteristic of offshore wind farms
is the large number of turbines in
the wind farm. These turbines have a
negative impact on each other because
of the wakes behind the turbines.
This leads to performance losses and
additional maintenance costs. ECN has
developed patented technology called
Active Wake Control (AWC). This wind
farm controller has been demonstrated
to increases the energy production.
The reasons wind farm operators
and developers are looking into the
possibilities of AWC technology are:
• AWC increases the wind farm annual
power production (typically 0.5-2.5%
depending on farm configuration)
• AWC reduces fatigue loads on wind
turbines (about 1-3%), increasing the from that of onshore wind farms. The
lifetime by 4-20% while at the same
time reducing failure rates (O&M
costs saving)
• Implementing AWC on a 350MW
offshore wind farm could potentially
result in around 20 GWh of
additional power production and
an increase in yearly cash flows
of around 2 million euros for the
operator (fast return on investment)
• When used during the design phase
of the wind farm, AWC reduces
electrical infrastructure costs by
reducing the spacing between the
wind turbines.
Wind farm controllers are very relevant
for all offshore wind farms. Considering
that increasing annual energy
production is the single easiest way
to lower the cost of energy, ECN will
continue to work in bringing this to the
market on a large scale. At this moment
in time, ECN is participating in the EU
Demowind program on this topic.
LARGER CAPACITY FACTORS
Capacity factor refers to the
percentage of time when the wind farm
operates at its maximum efficiency.
To do this, the wind turbines should
harvest energy efficiently even at low
wind speeds and also have a very
low down time. ECN contributes
by developing larger rotors as
well as working on the design and
maintenance of support structures.
For larger rotors, ECN’s tool to calculate
the performance of airfoils (the wing
profiles of the blades) called RFOIL
needs to be improved with advanced
physics. In that way, the tool which has
been applied to design the majority
of all wind turbines is capable to
accurately design future large rotors.
The operation and maintenance of
offshore wind farms significantly differs
accessibility of the turbines is especially for a lower price, and become even
hampered when the wind is strong and
waves are high. This means turbines
must be robust and redundancy is
an important asset. ECN has been
working on the O&M optimiser that
collects the data within an offshore
wind farm. Using smart algorithms,
an operator can learn a lot from the
data and make intelligent decisions.
Which components have failed? Were
they too heavily loaded? To improve
accessibility, ECN and partners develop
and model access systems to allow for
easy and safe transport of personnel to
a wind farm.
OFFSHORE WIND CONDITIONS
Wind measurements at the North
Sea have been performed by ECN in
the Dutch part of the North Sea since
2000. First using a measurement mast
near IJmuiden, later a 100 metre-high
met mast was installed more than 80
kilometres from the coast. For several
years ECN has been operating remote
sensing LiDAR systems at several
locations in the North Sea aiming to
characterise the atmospheric boundary
layer up to 300m height. These data
are very important for the development
of the soon to be built wind farms at
Borssele and Hollandse Kust. Ultimately
a good understanding of wind
conditions and variability is the most
critical part of the business case for an
offshore wind farm.
NOT JUST ONE SOLUTION
The development and implementation
of offshore wind power is a multi-
disciplinary effort. This article
highlighted several R&D developments
that already have contributed or will
contribute to cost-effective offshore
wind power. The fact that the Dutch
government, as well as the European
Union is assisting with cohesive R&D
programmes helps a great deal.
Turbines will need to become even
more effective, produce more energy
more reliable. This is a balancing act
which requires innovative technology,
brought quickly to the market. l
For more information on the R&D
programme and innovations of
ECN in the field of wind energy,
please visit our website
www.ecn.nl/expertise/wind-energy/
www.europeanenergyinnovation.eu