Application note no. 05- Signature1000

Optimizing the performanceof renewable-energy turbines
in the Netherlands

Challenge

Tocardo, designer and producer of tidal and free-flow water turbines, needed to measurewater speed through the rotor of the turbines. This was necessary to further verify andoptimize the turbines’ production of energy.

Solution

Installing the Signature1000 current profiler on Tocardo’s turbines, using its 16 Hz capacity
to measure the velocity through the turbine rotor.

End user value“Even though we use the Signature1000 in a challenging environment,this instrument provides us accurate data to confirm the performanceof our turbines. We also discovered that by looking at the [data] we could
check the correct orientation of the blades.”- Aymeric Buatois
Systems Engineer, Tocardo InternationalThe background story

Contributing to sustainable energy production
from tidal turbines
Replacing fossil fuels with sustainable
alternatives is both necessary andchallenging. Meanwhile, tidal and riverenergy are among the key sources ofrenewable energy available.

something you want to keep track of, since it reduces
the efficiency of the turbine’s performance and willcause fatigue on your turbine. Turbulence may be
defined as the velocity variation around its presentmean.
The Signature1000 is the only instrument able tocollect current profile data with a 16 Hz sampling
rate, which is a significant increase compared tothe older 4 Hz models. As the blades have amaximum turn rate of two revolutions per second,
the Signature1000 makes it possible to collectsufficient data, even though it’s mounted behind theturning blades. It gathers important data to be
used to define the mean velocity and its turbulence
intensity. Another important aspect is the need forhigh-precision timing on the data transmission.
With the use of Ethernet communication, Tocardo
was able to achieve tight network synchronization
with the blades or other sensors.

How does Tocardo use the Signature1000
current profiler in its work to harvest cleanand sustainable tidal energy?
Renewable energy company Tocardo is on a mission
to contribute to clean, sustainable and predictableenergy. It does this by designing turbines that canharvest power from tidal flows and rivers.
To reach its goals, Tocardo has decided to use theSignature1000 to optimize the operational performanceof its tidal turbines.

Monitoring the impact of water velocity andturbulence

Verifying turbine performance
What challenges has the Signature1000 helped
Tocardo resolve?

“We chose the Signature1000 since it could measurewater velocity at high sampling frequency. This
instrument was also selected due to its ability tomeasure water speed through the rotor of the turbineswith a single beam,” says Aymeric Buatois, Systems
Engineer at Tocardo.

“We use the Signature1000 to verify the performanceof the turbines. Mainly to check the Cp/Lambdacurve. [The Cp/Lambda curve is used to determine
the rotor power for any combination of water androtor speed.] We also discovered that by looking at
the profile of the amplitude, we could check thecorrect orientation of the blades,” says Buatois.

The Signature1000 also helps define the amount ofturbulence in fast tidal currents. And turbulence isTocardo International uses the Signature1000 to verify the performance of their turbines. The data from the instrument
also helps Tocardo check the correct orientation of the blades.

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Application note no. 05

The background story

The Signature1000 is mounted on turbines that are installed in three different locations in the Netherlands: the TTC test
facility in Den Oever, in the Eastern Scheldt storm surge barrier, and on the BlueTEC floating tidal energy platform Texel.

The amplitude data contains information about thereturned echo of the transmitted acoustic signal.
The blades act as a strong reflector and can berecognized during the validation of the data. Thereflection also differs depending on the orientationof the blades.

The velocity is important to determine the performance of the turbine. The amplitude and correlation
are also useful to check the validity of the data,”
says Aymeric Buatois.
“Even if we use the Signature1000 in a challenging
environment, it provides us accurate data to confirm
the performance of our turbines. Next to watervelocity, shear profile and turbulence measurements
are also important, but not yet used a lot,” Buatois
says.

The Signature1000 is mounted on a turbine that is
installed in Den Oever, a tidal testing center that
operates in the Afsluitdijk tidal barrage, one of themost prestigious civil structures built in the 20thcentury. The 33 km long dam was built in the 1930’s
to protect the Netherlands from flooding.

Buatois appreciates that the Signature1000 has
helped Tocardo produce complete documentation.

“One Signature1000 is mounted on top of one turbine
and it measures the velocity through the rotor withthe fifth beam of this ADCP. Another one is mounted
in the tail of the turbine, also measuring with thefifth beam of this instrument,” explains Buatois.

“It allows us to acquire data in real time with ourown software to have the water velocity a part ofour complete data acquisition system.”
The data have been useful in other ways: theSignature1000 has contributed to the calibrationand further improvements of the CFD softwaremodel, and provided further design improvements
relevant for performance and reliability. Additionally,it has helped provide accurate energy yield predictions
for individual devices, and it has helped optimize
array layouts.

The Signature1000 instruments are mounted horizontally. Thus, the fifth beam of the instrumentdoes horizontal measurements.
At present Tocardo is working towards commercial
application of in-shore projects such as demonstrated
at the Afsluitdijk and the Oosterschelde stormbarrier. Just recently the company announced theapplication of the first 1 MW offshore tidal arraywith four turbines on a Universal Floating Structure(UFS) in Canada’s Bay of Fundy.

Laying the foundation for future upscaling
Nortek has played an active role in setting up
functional solutions for Tocardo’s projects. By
cooperating closely, Tocardo and Nortek succeededin overcoming the initial EMC problems.

Providing vital data
This turbine facility will produce vital data and provide
valuable experience with turbine installations(arrays).
“We mainly get velocity data from the Signature1000.
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Application note no. 05

The background story
Why was solving the EMC issue of importance?

power. This installation in the Eastern Scheldt is thelargest tidal energy project in the Netherlands aswell as the world’s largest commercial tidal installationof five turbines in an array. This commercial installationconsists of a 1.2 MW array of five turbines. The special
design of this installation enables the turbines togenerate electricity during ebb and flood.

EMC, or Electromagnetic Compatibility, refers toelectronic noise. Each turbine creates an EMC noisespectrum. This is picked up by the communicationand power line and adds noise to the electronics of
the instrument. This caused a high level of signal
noise and a decreased measurement range.

As the world’s only turbine manufacturer capable ofinstalling this type of multi-turbine installation, Tocardo
can now monitor the array in turbulent waters andsee how the turbines interact. This information isnecessary for future upscaling and the commercial
rollout of such tidal projects.

“The support provided by Nortek is excellent, bothin quality and reactivity,” reports Buatois. “The way
Nortek solved the EMC issue with the ADCP wasreally valuable. Nortek modified the internal filterof the power supply to enable the 20 m range of theSignature1000.”

Special care was given to the environmental challenges
around this operation as the Eastern Scheldt is a
protected area. Monitoring will therefore be an importantpart of the project.

Nortek analyzed the present noise spectrum andcreated a filter to reduce the EMC noise that interferedwith the instrument. This is useful because theSignature can achieve a longer range when there isno added EMC noise onto the internal electronics.

Producing energy from a floating tidal 1 MW
system in Canada’s Bay of Fundy

Tocardo also asked Nortek to electrically disconnect
the grounding titanium plate on the back of theSignature to prevent cathodic erosion.

Tocardo has announced a collaboration with Minas
Energy and International Marine Energy Inc (IME). In
late 2017, these partners will deploy four 250 kW
rated T2 bi-directional turbines in the Minas Passage,
Bay of Fundy, Canada. The turbines will be attachedto Tocardo’s patented semi-submersible Universal
Floating Platform Structure to form a 1 MW systemheld in place by catenary mooring systems.

Providing renewable energy as sea levels
rise
In a greater societal context, this technology iscontributing to help solve the world’s energy needs
in a sustainable manner. It is an uncomfortable fact,
but rising sea levels will actually make tidal energy
even more relevant as the effects of climate change
become a reality.

In this new collaboration, Tocardo’s technology will
be tested at the Fundy Ocean Resource Centre forEnergy (FORCE) in the Minas Passage.

Tidal energy has several advantages: the amount ofenergy that can be produced is extremely predictable– the tide appears every day. Also, the turbines are
installed in the water and are not in sight, somethingthat has been a controversial issue in connection
with wind turbines.

Preparing for future upscaling and thecommercial rollout
In addition to the TTC test facility in Den Oever, Tocardo
now successfully uses the Signature instrumentson two additional locations in the Netherlands: theEastern Scheldt storm surge barrier and on a floating
tidal energy platform in the Waddenzee.
The Eastern Scheldt storm surge barrier is part of
the famous Dutch Delta Works. These barriers havebeen put in place to protect the Netherlands fromflooding from the North Sea. The system that has
now been set up in this location demonstrates how
future water defenses can also provide hydroelectric

Tocardo International chose the Signature1000 since it could
measure water speed through the rotor of the turbines. TheSignature1000 can be mounted on top of one turbine andmeasure the velocity through the rotor with the fifth beam ofthis instrument. Another Signature1000 can be mounted in
the tail of the turbine.
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Application note no. 05

Technology background

Explaining thetechnology
The Signature1000 provides an ideal platform for
turbulence studies, while also fulfilling standard
current profiling needs.
Built on the advanced AD2CP platform, theSignature1000 is designed for unprecedented
performance in high-energy turbulent environments,
while also giving users the freedom to employ twoor more measurement schemes at one time.
This system offers users the convenience of:
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Smaller physical size and lighter weight
Two or more simultaneous measurement modes
True broadband processing, implementing themost appropriate scheme
Tight time synchronization of multiple instruments
over Ethernet
Ethernet interface for direct network connection
to instrument and 20 Mbit data download
Continuous rapid sampling in burst mode(up to 16 Hz)

Nortek’s Signature1000

www.nortekgroup.com