Quotient

Quantification, Optimisation, and Environmental Impacts of Marine Renewable Energy

Cluster Leader: Dr Simon Neill, Bangor University

The UK Government has a target to produce 30% of its electricity from renewable sources by 2020. Waves and tides contain vast amounts of energy, and the UK has a significant share of this resource. The northwest European shelf seas harbour an estimated 27 GW of tidal and wave energy, but only 7MW has been installed to date. Reduction in the cost of offshore wind for example has led to increased UK government investments in this area, with little support for commercialisation of tidal energy. As a result, UK tidal energy companies are looking at markets further afield (France, SE Asia), and at niche markets. This shift has also led to prioritising research into tidal energy cost reduction. In addition, tidal and wave resources are incorporated in increasingly joined-up thinking about Offshore Renewable Energy (ORE) research opportunities, e.g. for shared infrastructure, foundations and grid connections, with aims to benefit from the rising popularity and low cost of offshore wind energy.

The nature and interactions of marine renewable resources, however, are not yet fully understood, nor is how these resources will evolve as a result of sea-level rise and future changes in weather patterns. It is still uncertain how best to optimise marine energy installations so that these variable resources can provide a firm source of power with minimal environmental impacts.

Quotient aimed to improve understanding of the role of marine renewables in the future energy mix, specifically looking at resource assessment and optimisation, and interactions between renewable energy devices and the environment.

Aims:

The Cluster addressed the following research themes:

  • Resource assessment.
  • Optimisation.
  • Impacts of renewable energy devices on the environment.
  • Impacts of the environment on renewable energy devices.

Research activities:

  • Investigating feedbacks between renewable energy devices and the environment.
  • Assessing the effects of tides and waves on turbulence and on turbine performance and resilience.
  • Using supercomputing to conduct high-resolution 3D modelling across a range of spatial and temporal scales, validated and parameterised by field observations and laboratory experiments:
  • On a shelf-sea scale, the Cluster looked at oceanographic conditions through hydrodynamic modelling and assessed the capacity and optimal locations for wave and tidal arrays.
  • On a regional scale, the Cluster characterised turbulence variation in space and time and the optimal configuration of devices on the seabed. 
  • Forging international collaborations to:
  • Characterise tidal stream resources in France and the Gulf of California.
  • Assess the feasibility of utilising marine energy resources for Australia’s future energy mix.
  • Develop the tidal energy potential of the Lombok Strait, working towards unlocking 150 MW of capacity and the establishment of an Indonesian/South Korean Marine Energy Centre of Excellence.

Key findings:

  • Floating tidal devices are becoming more popular as they may be more cost-effective than submerged devices. Quotient research used computer modelling and direct measurements to characterise how these systems differ in performance under varying conditions.
  • Wakes generated by tidal turbines depend on both the intensity and length scale of ambient turbulence in the flowfield. Micro-siting and optimisation are critical therefore for the development of  smaller energy projects, with local conditions needing to be taken into account when planning array layouts.
  • The Cluster developed realistic velocity profiles of UK currents, and subsequently identified optimal sites for installation of multiple arrays. In collaboration with industry partners, the Cluster consistently led the research agenda in a move towards using realistic site conditions rather than idealised experiments.
  • The Cluster improved realistic flow and turbulence simulation models for individual devices at tidal array sites, with direct relevance for industries looking to install capacity with minimal interaction between devices.
  • When compared with field data, ocean models accurately predicted the strength of turbulence at tidal energy sites over long time periods. However, waves may affect the reliability of tidal energy devices as much as turbulence does. Therefore, models that include wave-current interaction are required for accurate resource assessment, particularly in exposed locations.

Publication highlights:

  • Neill, S, Angeloudis, A, Robins, P, Walkington, I, Ward, S, Masters, I, Lewis, M, Piano, M, Avdis, A, Piggott, M, Aggidis, G, Evans, P, Adcock, T, Zidonis, A, Ahmadian, R & Falconer, R (2018) Tidal range energy resource and optimization – past perspectives and future challenges. Renewable Energy 127: 763-778. https://doi.org/10.1016/j.renene.2018.05.007
  • Lewis, M.J., Palmer, T., Hashemi, R., Robins, P., Saulter, A., Brown, J., Lewis, H., Neill, S. (2019) Wave-tide interaction modulates nearshore wave height. Ocean Dynamics 69: 367. https://doi.org/10.1007/s10236-018-01245-z
  • Zangiabadi, E., Masters, I., Williams, A.J., Croft, T.N., Malki, R., Edmunds, M., Mason-Jones, A., and Horsfall, I. (2016). Computational prediction of pressure change in the vicinity of tidal stream turbines and the consequences for fish survival rate. Renewable Energy 101: 1141-1156. http://dx.doi.org/10.1016/j.renene.2016.09.063

The NRN-LCEE produced the following briefing on the policy implications of Multi-Land's research:

The role of marine renewable energy in a low carbon future

The Quotient researchers included:

Bangor University

  • Simon Neill                     
  • Matt Lewis                      
  • Peter Robins          

Cardiff University

  • Tim O'Doherty               
  • Sunqi Pan                      
  • Tim Ebdon     

Swansea University

  • Ian Masters                    
  • Michael Togneri           

           

Please see the ‘NRN-LCEE Final Overview 2013-2019’  for further details of the Cluster’s research.