Ocean Renewable Energy Potential, Technology, and Deployments: A Case Study of Brazil

Review of the marine energy environment-a combination of traditional, bibliometric and PESTEL analysis

Marine renewable energy is regarded as a nascent renewable energy resource that is less utilized due to a number of challenges in the sector. This paper focused on using both traditional and bibliometric analysis approaches to review the marine energy industry. It also assessed the various opportunities and challenges in the sector beyond technological challenges using PESTEL analysis. The results from the study identified the availability of renewable energy targets, international and national greenhouse gas (GHG) emissions reduction targets, job creation, skill transfer from offshore industries, renewable support, and low GHG emissions as the major opportunities for the sector. The challenges in the sector include the lack of commonality in device designs, high initial capital costs, lack of appropriate legal and regulatory frameworks, lack of funding, fragmentations in regulatory institutions, bad macro-economic indicators in some countries, environmental challenges, the survivability of the various technologies in the harsh oceanic environment, and strong competition from other renewable energy sources. The outcome of the bibliometric analysis spanning from 2013 to 2023 shows that tidal power is the focus of research in the field, and most studies are either focused on ways to improve its efficiency in terms of technology or on the identification of resource potentials for the siting of the various marine renewable power systems. Recommendations such as strong cooperation between the government and private sector, increased public education, collaboration with existing players in the marine sector, and increased research and development, among others, were proposed for the development of the sector.

Modular Morphing Lattices for Large-Scale Underwater Continuum Robotic Structures

In this study, we present a method to construct meter-scale deformable structures for underwater robotic applications by discretely assembling mechanical metamaterials. We address the challenge of scaling up nature-like deformable structures while remaining structurally efficient by combining rigid and compliant facets to form custom unit cells that assemble into lattices. The unit cells generate controlled local anisotropies that architect the global deformation of the robotic structure. The resulting flexibility allows better unsteady flow control that enables highly efficient propulsion and optimized force profile manipulations. We demonstrate the utility of this approach in two models. The first is a morphing beam snake-like robot that can generate thrust at specific anguilliform swimming parameters. The second is a morphing surface hydrofoil that, when compared with a rigid wing at the same angles of attack (AoAs), can increase the lift coefficient up to 0.6. In addition, in lower AoAs, the L ∕ D ratio improves by 5 times, whereas in higher angles it improves by 1.25 times. The resulting hydrodynamic performance demonstrates the potential to achieve accessible, scalable, and simple to design and assemble morphing structures for more efficient and effective future ocean exploration and exploitation.

Remote Monitoring and Fault Diagnosis of Ocean Current Energy Hydraulic Transmission and Control Power Generation System

The development of clean and environmentally friendly energy is necessary to address significant energy challenges, and abundant sea current energy, which plays a key role in the decarbonization of our energy systems and has attracted increasing attention among researchers. In the present study, a remote monitoring and diagnosis system was designed in accordance with the requirements of a 50 kW hydraulic transmission and control power generation system. Hardware selection and software function requirement analysis were then performed. The causes of system faults were analyzed, the output fault types of the improved model were determined, and effective monitoring parameters were selected. The accuracy of traditional spectra in diagnosing faults is poor; however, the generalization capability of support vector machines (SVM) is robust. Thus, an improved particle swarm algorithm optimized SVM fault diagnosis model for the hydraulic transmission control power generation system was proposed to rapidly and effectively determine the key parameters. Remote monitoring software for the hydraulic transmission and control power generation system was also developed. The results of remote monitoring and diagnostic tests showed that the software was able to satisfy the functional requirements of the hydraulic transmission control power generation remote monitoring system, and the operation effect was consistent with expectations. By comparing the test accuracy of different diagnostic models, the improved PSVM model has the highest test accuracy with a classification accuracy of 99.4% in the case of normal operation, accumulator failure, relief valve failure and motor failure. In addition, the proposed diagnostic method was effective, thereby ensuring safe and reliable operation of the hydraulic transmission control power generation system.

Breaking-Down and Parameterising Wave Energy Converter Costs Using the CapEx and Similitude Methods

Wave energy converters (WECs) can play a significant role in the transition towards a more renewable-based energy mix as stable and unlimited energy resources. Financial analysis of these projects requires WECs cost and WEC capital expenditure (CapEx) information. However, (i) cost information is often limited due to confidentiality and (ii) the wave energy field lacks flexible methods for cost breakdown and parameterisation, whereas they are needed for rapid and optimised WEC configuration and worldwide site pairing. This study takes advantage of the information provided by Wavepiston to compare different costing methods. The work assesses the Froude-Law-similarities-based “Similitude method” for cost-scaling and introduces the more flexible and generic “CapEx method” divided into three steps: (1) distinguishing WEC’s elements from the wave energy farm (WEF)’s; (2) defining the parameters characterising the WECs, WEFs, and site locations; and (3) estimating elements that affect WEC and WEF elements’ cost and translate them into factors using the parameters defined in step (2). After validation from Wavepiston manual estimations, the CapEx method showed that the factors could represent up to 30% of the cost. The Similitude method provided slight cost-overestimations compared to the CapEx method for low WEC up-scaling, increasing exponentially with the scaling.

Where Renewable Energy Sources Funds are Invested? Spatial Analysis of Energy Production Potential and Public Support

Energy transition in the European Union (EU) is strongly related to public support from structural funds which enable member states to create new and renovate existing renewable energy source (RES) installations. However, in order to maximize benefits of these investments it is crucial to consider where RES funds are allocated, how it corresponds with RES potential in specific locations, and how future implementation of energy policies can be improved. In this study, RES development projects supported by EU funds, implemented in the period 2004–2019 in Poland, were analyzed in relation to solar, wind and biomass energy potential. The study was conducted with the use of agglomeration method and k-mean method to define clusters of local administrative units characterized by similar features of RES funds absorption and renewable energy production potential. The results obtained show that in the case of all energy sources there is no correlation between high RES funds absorption and energy production potential. The final conclusion of the research is that in order to boost energy transformation into more sustainable solutions, renewable energy production potential should be considered as a factor to allocate public financial support for future energy policy implementation.

Self-Adaptive Global-Best Harmony Search Algorithm-Based Airflow Control of a Wells-Turbine-Based Oscillating-Water Column

The Harmony Search algorithm has attracted a lot of interest in the past years because of its simplicity and efficiency. This led many scientists to develop various variants for many applications. In this paper, four variants of the Harmony search algorithm were implemented and tested to optimize the control design of the Proportional-Integral-derivative (PID) controller in a proposed airflow control scheme. The airflow control strategy has been proposed to deal with the undesired stalling phenomenon of the Wells turbine in an Oscillating Water Column (OWC). To showcase the effectiveness of the Self-Adaptive Global Harmony Search (SGHS) algorithm over traditional tuning methods, a comparative study has been carried out between the optimized PID, the traditionally tuned PID and the uncontrolled OWC system. The results of optimization showed that the Self-Adaptive Global Harmony Search (SGHS) algorithm adapted the best to the problem of the airflow control within the wave energy converter. Moreover, the OWC performance is superior when using the SGHS-tuned PID.