Optimisation of Tidal energy Converter Arrays

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Assessing the effects of Tidal Energy Converter array size on hydrodynamics of Ria Formosa (Portugal)

Publication . G-Gorbeña, Eduardo; Pacheco, André; Plomaritis, Theocharis A.; Sequeira, Claudia

This paper investigates the effects of Tidal Energy Converter (TEC) array size at a tidal channel on flood/ebb discharges at multi-inlet coastal lagoon by applying numerical modelling. The paper presents a case study for the Faro-Olhão inlet in the Ria Formosa (Portugal), a potential site for tidal in-stream energy extraction. Arrays of up to 11 rows with 5 TECs each were studied to assess impacts on inlets discharges changes. For the particular cases assessed the results show that tidal energy extraction will have a greater impact on Ancão and Armona inlets discharges together with the Faro-Olhão inlet. Future work is directed to include impacts on sediment dynamics and optimise TEC array size as a function of multiple design variables subject to environmental constraints.

2017Journal article

Open Access

Deployment characterization of a floatable tidal energy converter on a tidal channel, Ria Formosa, Portugal

Publication . Pacheco, André; G-Gorbeña, Eduardo; Plomaritis, Haris; Garel, Erwan; Gonçalves, J. M. S.; Bentes, L.; Monteiro, P.; Afonso, Carlos; Oliveira, Frederico; Soares, C.; Zabel, F.; Sequeira, Claudia

This paper presents the results of a pilot experiment with an existing tidal energy converter (TEC), Evopod 1 kW floatable prototype, in a real test case scenario (Faro Channel, Ria Formosa, Portugal). A baseline marine geophysical, hydrodynamic and ecological study based on the experience collected on the test site is presented. The collected data was used to validate a hydro-morphodynamic model, allowing the selection of the installation area based on both operational and environmental constraints. Operational results related to the description of power generation capacity, energy capture area and proportion of energy flux are presented and discussed, including the failures occurring during the experimental setup. The data is now available to the scientific community and to TEC industry developers, enhancing the operational knowledge of TEC technology concerning efficiency, environmental effects, and interactions (i.e. device/environment). The results can be used by developers on the licensing process, on overcoming the commercial deployment barriers, on offering extra assurance and confidence to investors, who traditionally have seen environmental concerns as a barrier, and on providing the foundations whereupon similar deployment areas can be considered around the world for marine tidal energy extraction.

2018Journal article

Open Access

Assessing the effects of Tidal Energy Converter array size on hydrodynamics of Ria Formosa (Portugal)

Publication . González-Gorbeña, Eduardo; Pacheco, André; Plomaritis, Theocharis A.; Sequeira, Claudia

2017Conference object

Open Access

Cost-benefit analysis of tidal energy production in a coastal lagoon: the case of Ria Formosa – Portugal

Publication . Rodrigues, Nuno; Pintassilgo, Pedro; Calhau, Francisco; G-Gorbeña, Eduardo; Pacheco, André

The energy that can be extracted from tidal currents is one of the most promising renewable energy sources due to its high density/predictability. Within this paper this energy source is evaluated economically respecting sustainability principles. This evaluation contrasts from previous studies due to the application of a cost-benefit analysis based on a hydro-morphodynamic model, and moving away from the classic proxy of wind energy. It further includes, via the Monte Carlo method, a probabilistic underpinning to the project. The hydro-economic model was applied to a tidal energy project using an Evopod 1:4th scale prototype, based on a real deployment of an Evopod 1:10th scale device in the Ria Formosa, Algarve. The results show that, under the current costs and benefits, the project is not economically viable. However, there are admissible parameter ranges that make the project viable such as significant reduction of investment costs, increased capacity factors and favourable energy prices. This novel methodology has potential to be applied to other tidal energy projects on estuarine systems worldwide, and consists of a comprehensive modelling approach, including the technical, environmental, and socio-economic dimensions of the project, not only in a deterministic setting but also in a probabilistic one.

2021Journal article

Restricted

Estimating the optimum size of a tidal array at a multi-inlet system considering environmental and performance constraints

Publication . González-Gorbeña Eisenmann, Eduardo; Pacheco, André; Plomaritis, Theocharis; Ferreira, Oscar; Sequeira, Claudia

This paper investigates the optimum tidal energy converter array density at a tidal inlet by applying surrogate-based optimisation. The SBO procedure comprises problem formulation, design of experiments, numerical simulations, surrogate model construction and constrained optimisation. This study presents an example for the Faro-Olhão Inlet in the Ria Formosa (Portugal), a potential site for tidal in-stream energy extraction. A 35 kW Evopod™ floating tidal energy converter from Oceanflow Energy Ltd. has been used for array size calculations considering two design variables: (1) number of array rows, and (2) number of tidal energy converter per row. Arrays up to 13 rows with 6–11 tidal energy converters each are studied to assess their impacts on array performance, inlets discharges and bathymetry changes. The analysis identified the positive/negative feedbacks between the two design variables in real case complex flow fields under variable bathymetry and channel morphology. The non-uniformity of tidal currents along the array region causes the variability of the resource in each row, as well as makes it difficult to predict the resultant array configuration interactions. Four different multi-objective optimisation models are formulated subject to a set of performance and environmental constraints. Results from the optimisation models imply that the largest array size that meets the environmental constraints is made of 5 rows with 6 tidal energy converter each and an overall capacity factor of 11.6% resulting in an energy production of 1.01 GWh year−1. On the other hand, a higher energy production (1.20 GWh year−1) is achieved by an optimum array configuration, made of 3 rows with 10 tidal energy converters per row, which maximises power output satisfying environmental and performance restrictions. This optimal configuration permits a good level of energy extraction while having a reduced effect on the hydrodynamic functioning of the multi-inlet system. These results prove the suitability and the potential wide use of the surrogate-based optimisation method to define array characteristics that enhance power production and at the same time respect the environmental surrounding conditions.

2018Journal article

Open Access