Tidal Turbine Testing (TTT) - Phase 1 to 3
Free stream tidal turbine technology has great potential to be a significant renewable energy resource in many coastal regions. The aim of the Invest-NI funded CASE project is to accelerate the commercialisation of this technology by stemming the gap between laboratory scale tank testing and field scale deployments (TRL levels 4-6).
The research group spanning three phases of the project investigated many areas; some of these are highlighted below:
Tandem turbine testing – interactions between devices
The interaction between the two turbines is investigated by pushing test in a calm water lake. Investigation of both in-plane and in-line configurations for the two turbines was undertaken. The research found no discernible interaction between the device when In-plane. For in-line spacing, at close proximity, two turbine diameter (2D) spacing between upstream and downstream devices resulted in a 63% reduction in performance of the downstream turbine. At 6D separation the performance of the second turbine remains poor at 59% reduction. It was identified however that a 1.5D lateral and 3D downstream displacement resulted in no noticeable interaction with the downstream device. These results are significant for developers with limited footprint seeking to maximise power output.
Control system – Speed control
The research highlights the importance of a tidal turbines control, which has a significant impact on performance characteristics when challenged with nonideal conditions. The research showed a 13.7% higher peak performance when closed-loop control was used in the tidal environment. This has significant implications for developers transitioning between simple lab experiments and field deployments.
Uncertainties in flow characteristics
By developing an alternative methodology for the use Acoustic Doppler Profiler (ADP) measurements for tidal energy resource characterisation, existing international standards have been challenged to reduce the error from ADP measurements in calculating the Mean Representative Velocity (MRV). This initial investigation has led to further challenges of the IEC TC114:62600-200 standard which will be issuing a second edition. The benefit of reducing the error in the MRV is critical due to its cubic relation to Annual Energy Prediction, a key metric used in tidal energy project developments, globally.
Impact of Research
This industry-led research has benefitted the partners to the project with a reported £200k of actual and potential contracts for industry. It has also resulted in the establishment of the QUB tidal test site in Strangford Narrows as part of the EU H2020 Marinet2 Transnational Access Programme.
Further impact has been established in challenging existing and recommending methodologies for the development of future international standards, for example the IEC TC114:62600.
Major grants and funding
Invest-NI funded research through the CASE competency centre.
Jeffcoate, P., Whittaker, T., Boake, C., Elsaesser, B., 2016. Field tests of multiple 1/10 scale tidal turbines in steady flows. Renew. Energy 87, 240–252. https://doi.org/https://doi.org/10.1016/j.renene.2015.10.004
Frost, C., Benson, I., Jeffcoate, P., Elsäßer, B., Whittaker, T., 2018. The Effect of Control Strategy on Tidal Stream Turbine Performance in Laboratory and Field Experiments. Energies 11, 1533. https://doi.org/10.3390/en11061533
Rathnayake, U., Folley, M., Gunawardane, S.D.G.S.P., Frost, C., 2020. Investigation of the Error of Mean Representative Current Velocity Based on the Method of Bins for Tidal Turbines Using ADP Data. J. Mar. Sci. Eng. 8, 390. https://doi.org/10.3390/jmse8060390
Jeffcoate, P., Elsaesser, B., Whittaker, T., Boake, C., 2014. Testing Tidal Turbines - Part 1: Steady Towing Tests Vs Tidal Mooring Tests, in: International Conference on Offshore Renewable Energy. pp. 55–87.
Frost, C., Benson, I., Elsäßer, B., Starzmann, R., Whittaker, T., 2017. Mitigating Uncertainty in Tidal Turbine Performance Characteristics from Experimental Testing, in: European Wave & Tidal Energy Conference. Cork.
Torrens-Spence, H., Schmitt, P., Frost, C., Benson, I., Mackinnon, P., Whittaker, T., 2017. Assessment of the Flow Characteristics at Two Locations in an Energetic Tidal Channel, in: European Wave & Tidal Energy Conference. Cork.
This research involves a collaboration between Queen's University Belfast and the following partners:
ARR Ltd - http://www.arrltd.co.uk/wp/
Sustainable Marine Energy & Schottel Hydro - https://www.sustainablemarine.com/
Ocean Flow Energy - http://www.oceanflowenergy.com/
CNR-INM - http://www.inm.cnr.it/
McLaughlin & Harvey - https://www.mclh.co.uk/
QED Naval - https://qednaval.co.uk/
ORE Catapult - https://ore.catapult.org.uk/
Sustainable Development Goals
The Tidal Turbine Testing (TTT) projects align with the following sustainable energy goals:
#7 – affordable and clean energy
#11 – sustainable cities and communities
#13 - climate action
#14 – life below water
Find out more
- Dr Carwyn Frost
School of Natural and Built Environment,
Queen’s University Belfast
Early Career Researchers who worked on the project:
Dr Penny Jeffcoate – https://www.linkedin.com/in/penny-jeffcoate-3990573a/
Dr Carwyn Frost - https://www.linkedin.com/in/carwyn-frost-950a5b75/
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VIDEO OF TIDAL TURBINE TESTING ON STRANGFORD LOUGH