Comparison of Free Vortex Wake and BEM Structural Results Against Large Eddy Simulations Results for Highly Flexible Turbines Under Challenging Inflow Conditions

Throughout wind energy development, there has been a push to increase wind turbine size due to the substantial economic benefits. However, increasing turbine size presents several challenges, both physically and computationally. Modeling large, highly flexible wind turbines requires highly accurate models to capture the complicated aerodynamic response due to large deflections and nonstraight blade geometries. Additionally, development of floating offshore wind turbines requires modeling techniques that can predict large rotor and tower motion. Free vortex wake (FVW) methods model such complex physics while remaining computationally tractable to perform the many simulations necessary for the turbine design process. Recently, a FVW model—cOnvecting LAgrangian Filaments (OLAF)—was added to the National Renewable Energy Laboratory engineering tool OpenFAST to allow for the aerodynamic modeling of highly flexible turbines along with the aerohydro- servo-elastic response capabilities of OpenFAST. In this work, FVW and low-fidelity blade-element momentum (BEM) structural results are compared to high-fidelity simulation results for a highly-flexibly downwind turbine for varying TI, shear exponent, and yaw misalignment conditions. Through these comparisons, it was found that for all considered quantities of interest, SOWFA, OLAF, and BEM results compare well for steady inflow conditions with no yaw misalignment. For OLAF results, this strong agreement was consistent for all yaw misalignment values. The BEM results, however, deviated significantly more from SOWFA results with increasing absolute yaw misalignment. Differences between OLAF and BEM results were dominated by yaw misalignment angle, with varying shear exponent and TI leading to more subtle differences. Overall, OLAF results were more consistent than BEM results when compared to SOWFA results under challenging inflow conditions.

THE POTENTIAL OF OFFSHORE WIND ENERGY IN THE EAST COAST OF PENINSULAR MALAYSIA, TERENGGANU

A detailed understanding of wind characteristics is very important for offshore wind energy development. A 26 years of wind speed data (1993-2018) were retrieved using Radar Altimeter Database System (RADS) to assess the potentiality of offshore wind energy in Terengganu waters. Seasonal assessment and wind energy density derivation was carried out to choose the potential location for wind energy development. This study highlights the multi-criteria site suitability analysis using Analytical Hierarchy Process (AHP) and is supported by the geographical information system (GIS) by developing a suitability map. The site suitability analysis considered a few criteria, such as seasonal assessment, physical, environmental, and wind resources. Theoretically, the Terengganu area possessed strong wind during the Northeast monsoon with an average of 3.46m/s and experienced up to 6 m/s during this monsoon. For offshore areas, which is more than 50km from the coastline, Terengganu waters experienced a maximum of wind speed more than 5m/s and the average wind power density varied from 40W/m2 to 60W/m2. While Tenggol Island possessed a maximum wind speed between 3m/s to 5m/s and produce up to 40W/m2 of average wind energy density. From the suitability analysis, a few areas are identified as the potential location with an optimum resource of wind energy. Even though, Malaysia is located at low wind area, this research will help organisation or governments to plan suitable technology and policy for harvesting wind energy.

Geoscience Solutions for Sustainable Offshore Wind Development

Low carbon energy infrastructure, such as wind and solar farms, are crucial for reducing greenhouse gas emissions and limiting global temperature rise to 1.5°C. During 2020, 5.2 GW of offshore wind capacity went into operation worldwide, taking the total operational capacity of global offshore wind to 32.5 GW from 162 offshore windfarms, and over 200 GW of new capacity is planned by 2030. To meet net-zero targets, growth of offshore wind generation is expected, which raises new challenges, including integration of offshore wind into the natural environment and the wider energy system, throughout the wind farm lifecycle. This review examines the role of geosciences in addressing these challenges; technical sustainability challenges and opportunities are reviewed, filtered according to global governance priorities, and assessed according to the role that geoscience can play in providing solutions. We find that geoscience solutions play key roles in sustainable offshore wind energy development through two broad themes: 1) windfarm and infrastructure site conditions, and 2) infrastructure for transmission, conversion and energy storage. To conclude, we recommend priorities and approaches that will support geoscience contributions to offshore wind, and ultimately enable sustainable offshore wind development. Recommendations include industry collaboration and systems for effective data sharing and archiving, as well as further research, education and skills.