Avian Macro-Avoidance of an Offshore Wind Farm in the Taiwan Strait, Investigated Using Surveillance Radar

Taiwan Strait is one of the potential wind farm in the world. Cooperate with the development of national policies, thousands of offshore wind turbines will be installed in Taiwan Strait. In order to enable offshore wind turbine foundation to be erected in the ocean for a long time, the offshore structure facilities are protected by sacrificial anode or impressed current of today. This study utilized the MIKE21 numerical model, combined with ocean parameters such as sea waves and tidal current to simulate the change of the diffusion concentration and diffusion range of the materials released by the aluminum sacrificial anode blocks by the Changhua offshore wind farm located on Taiwan Strait in winter and summer, thus to evaluate the impact on the marine environment.

Wind is one of the cleanest renewable energy resources. Through the “Thousand Wind Turbines Project”, Taiwan is planning to increase the proportion of power generation from renewable energy and has set a target of 5.7 GW for offshore wind by 2025. The effects of future offshore wind farms (OWFs) over the Taiwan Strait on the atmospheric environment have not been evaluated. This study examined the potential effects of proposed OWFs on the atmospheric environment if the OWFs had existed during Tropical Storm Haitang (2017) by using Weather Research and Forecasting (WRF) model. A small set of ensemble simulations was conducted for studying the sensitivity of the ambient conditions in the region to the wind farm locations, the number and density of the turbines, and the initial time of simulations. Following the landfall and northward movement of Tropical Storm Haitang, a series of complex interactions between the typhoon circulation and the wind farm emerged, including small time slots of wake effect and mountain blocking effect. The combination of these rapidly changing OWFs-related effects contributed to a weak reduction in precipitation (− 1.08 mm) and hub-height wind speed (− 0.25 m s−1), as well as minimal warming near the surface (+ 0.13 °C) over southern Taiwan.

Offshore wind farm is a key item in green energy and sustainable development. The Taiwan strait owns the world-class wind farm with average wind speed of 12 m/s and a potential for 3000 hours/year of power generation. Compared to wind turbines on land, the offshore wind turbine provide more stable power and less obstacles as well as less power loss. The potential and advantages of offshore wind farm development in the Taiwan strait has become the aims of the Taiwan government policy from now to 2025. This research will collect the historical climate data (wind and wave) of the Taiwan offshore wind farm in the Chan-hwa county. Combined the productivity loss respected to the installation of wind turbine due to different wind speed effect, as well as the productivity loss respected to the construction of pile foundation due to different wave height effect, this study will build up a total project duration forecast system based on the historical climate data of the offshore wind farm. Even the literature views from the experienced projects in North Europe including UK, Netherland and Spain, the climate uncertainty still plays a significant factor of the total construction duration for offshore wind farm. The results of this research can provide a more scientific and reliable duration forecast for future offshore wind farms construction in Taiwan.

Offshore wind farms have recently emerged as a renewable energy solution. However, the long-term impacts of wind turbine noise on fish chorusing phenology are largely unknown. We deployed a hydrophone 10 m from a foremost turbine in Taiwan situated at the Miaoli offshore wind farm (Taiwan Strait) for two years to investigate sound levels and assess the potential influence of turbine noise on seasonal fish chorusing patterns during 2017 and 2018. Wind turbine noise (measured in the 20–250 Hz frequency band) was significantly higher in autumn and winter (mean SPL: 138–143 dB re 1 μPa) and was highly correlated with wind speed (r = 0.76, P < 0.001). During both years, fish chorusing exhibited a consistent trend, that is, beginning in spring, peaking in summer, decreasing in autumn, and absent in winter. Our results show the noise from a single turbine during the two-year monitoring period did not influence the seasonal fish chorusing (r = −0.17, P ≈ 1). Since the offshore wind farm installations are growing in magnitude and capacity across the Taiwan Strait, this study for the first time provides baseline operational sound levels and an understanding of the fish seasonal vocalization behavior at the foremost turbine of the first wind farm in Taiwan. The results presented here provide useful insights for policymakers and constitute a reference starting point for advancing knowledge on the possible effects of wind turbines on fish chorusing in the studied area.

The first data set of seasonal marine environment and euphotic zone integrated primary production (IP) variations in the Taiwan Strait was reported. The measured annual IP was 123±86 gC m-2 y-1 (338±235 mgC m-2 d-1), and its seasonal variations can be described with a left-skewed normal distribution curve. The average seasonal IP values from the highest to the lowest were summer (664±270 mgC m-2 d-1), autumn (350±118 mgC m-2 d-1), spring (202±110 mgC m-2 d-1) and winter (137±68 mgC m-2 d-1). The lowest IP was during the nutrient-rich winter because it had a short insolation duration, low incident photosynthetic active radiation (PAR) and low light transmission (shallow euphotic zone depth) due to strong vertical mixing. In contrast to the winter, the highest IP was during the nutrient-depleted summer, which had a long insolation duration, high incident PAR and high light transmission (deeper euphotic zone depth). In addition, the heterotrophic nutrients from upwelling in the south might also support the highest IP in summer. As three primary water masses exist in the Taiwan Strait and three of them have different characteristics, different mixing ratios of water masses may cause different chemical and hydrographic conditions, which leads to different levels of Chl a concentrations and primary production. It is worth to mention that offshore wind farm (OWF) construction in the Changyun Rise (CYR) of the Taiwan Strait is on-going. As primary production is the foundation for a marine ecosystem and supports the food web and fish stock, the results of this research can not only be used as the baseline for evaluating the OWF impact on the marine ecosystem but also be used for assessing their influence on fishery resources.

Gao, C.; Zheng, C.W.; Zhang, G.; Han, Y.; Tian, F.; Liu, X.; Wang, L.; Zhang, D., and Xiao, Z., 2020. Long-term projection of wind potential in the China seas. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 396–403. Coconut Creek (Florida), ISSN 0749-0208.This study conducts the mid-long term predictions and assesses the multi-year average offshore wind energy in the China seas for the next five years based on CMIP5 wind data, in hope of providing reference for the long term prediction of wind energy. Results show that (1) large areas with multi-year average wind power densities (WPD) greater than 350 W/m2 are mainly found throughout the Ryukyu Islands and the Taiwan and Luzon Straits in the southeastern area of the Indo-China Peninsula. (2) From 2015-2019, the WPD in the Bohai Sea, Taiwan Strait and Beibu Gulf will be lower than the multi-year average level and thus will be similar to the multi-year average in the Yellow Sea and Gulf of Thailand but greater than the multi-year average in the East China Sea and South China Sea. (3) The predicted occurrences of exploitable wind speeds of the East China Sea and South China Sea are promising for the next five years, exceeding 60%. A value above 40% is predicted for the Yellow Sea, and a lower value is anticipated for the Bohai Sea. (4) The predicted occurrences of WPD > 50 W/m2 are more promising for the next five years.

The Taiwan Strait, to the west of Taiwan, is rich in wind energy resources and has the greatest offshore wind power potential in the world. Therefore, Taiwan has been actively expanding its offshore wind power industry in this area in recent years and expects to achieve the total installed capacity to 15.6 GW by 2035. Due to the large vessel traffic flow in Western Taiwan’s sea area, wind farms will inevitably reduce the navigable space and shadow some existing marine aids to navigation, thus worsening navigation safety. An approach using a fault tree analysis was used to carry out analysis of collision risk between ship-to-ship and ship-to-turbine. The vessel density distribution and traffic flow within the open sea of offshore wind farms would further increase to curtail the available navigable space. The shadowing effects along navigation channels would thereafter be worsened to raise the probability of collision risks in the sea. The results of the fault tree analysis revealed that if the ship is out of control, the time allowed to provide assistance is rather short, leading to the increase of collision risk extent between ships and wind turbines. Moreover, the study also found that unfit functions of the Vessel Traffic Service System and navigation aids and frequently and arbitrarily crossing the navigation channel of fishery vessels are the main causes of ship collisions. In order to effectively improve the navigation safety, competitive strategies for navigation safety are investigated and evaluated in this study. These strategies include making a complete plan for utilizing the whole sea, integrating the offshore vessel traffic service and management system, providing remote pilotage services, and building salvage vessels. The above promising strategies would enhance the navigation safety within the open sea. Collision risk might occur once marine accident occurs and no salvage vessel is available.

Influence of increasing noise at the offshore wind farm area on fish vocalization phenology: A long-term marine acoustical monitoring off the foremost offshore wind farm in Taiwan

Because of the potential of offshore wind energy in the Taiwan Strait, the development of offshore wind farm is feasible and cost-effective. With the global trends in green energy, Taiwan are actively promoting the “Thousand Wind Turbines” Project from 2012. Up to now, there are three met masts in different offshore demonstration wind farms established in 2015 and two mono-pile foundations completed in 2016. The objective is to install about 800 offshore wind turbines, and 450 onshore wind turbines prior to the year of 20-0. However, the planned location for potential offshore wind farms is close to the habitat of the Sousa chinensis (also called Indo-Pacific Humpback Dolphin or Chinese White Dolphin). Pile driving noise or operation noise have shown to cause behavioural disturbance or auditory damage to marine mammals. At a distance that is considered safe from PTS and TTS, noises from impact or vibratory pile driver are still high enough to disturb the behavior of marine mammals. In this study, underwater ambient noise measurements are shown to enhance the understanding of the soundscapes of the planned location for potential offshore wind farms. In the meantime, pile-driving noise measurements of two mono-pile foundations are made in 2016. For noise impact assessment, Range-dependent Acoustic Model (RAM-PE) is applied to calculate the range of noise impact zone with the sound speed profiles produced by POM-based Taiwan Coastal Ocean Nowcast/Forecast System (TCONFS). This work is supported by Ministry of Science and Technology of Taiwan, Taiwan Generations Corporation and Swancor Ind. Co., Ltd.

Taiwan is located on the Pacific seismic belt, and the soil conditions of Taiwan’s offshore wind farms are softer than those in Europe. To ensure safety and stability of the offshore wind turbine supporting structures, it is important to assess the offshore wind farms seismic forces reasonably. In this paper, the relevant seismic and geological data are obtained for Chang-Bin offshore wind farm in Taiwan Strait, the probabilistic seismic hazard analysis (PSHA) is carried out, and the first uniform hazard response spectrum for Chang-Bin offshore wind farm is achieved. Compared with existing design response spectrum in the local regulation, this site-specific seismic hazard analysis has influence on the seismic force considered in the design of supporting structures and therefore affects the cost of the supporting structures. The results show that a site-specific seismic hazard analysis is required for high seismic area. The paper highlights the importance of seismic hazard analysis to assess the offshore wind farms seismic forces. The follow-up recommendations and research directions are given for Taiwan’s offshore wind turbine supporting structures under seismic force considerations.

This paper introduces the development status of Offshore Wind Farms (OWFs) in the Taiwan Strait. We review some typical conflict cases between OWFs and maritime shipping in the Strait, the reasons why and how these conflicts occur when new OWF are ready to be built close the principal fairway passage through the strait.

Evaluating constraints on offshore wind farm installation across the Taiwan Strait by exploring the influence of El Niño-Southern Oscillation on weather window assessment

Various offshore wind farms have been proposed in the Taiwan strait with a long-term target of installing 4.2 gigawatts by 2030. The proposed projects will be in areas with various known faults and areal seismic sources which should be accounted for in design. A reliable prediction of site response for soil deposits is crucial for seismic loading evaluation of existing energy structures and for design of new structures including offshore wind farms in seismically active regions. This paper presents generic results of 1-D site response analyses based on work performed for an offshore wind power plant development site in the Taiwan strait. The deposits in the project area generally consist of layered deposits with liquefiable layers. The site response analyses were initially performed using two different open-source tools, DEEPSOIL and Cyclic 1D. Both equivalent linear and non-linear approaches were adopted for the analyses and additional evaluations were subsequently performed using PLAXIS 2D for comparison with the results from the open source tools. The results from the different tools were systematically compared and provided useful insight on peak ground (seabed) acceleration, acceleration time histories and shear strains at specific depths and design response spectra. The paper includes a discussion of the sensitivity of the outputs to various input parameters for each of the tools utilized in the analyses and the suitability and limitations of each approach for assessing liquefaction potential are also discussed.

Offshore wind farming is a growing presence in the renewable energy landscape but these ambitious projects rely on precise assessments of the hard to observe underwater landscape they will occupy before construction can even begin.<br/>Many governments around the world are moving toward renewable energy sources to meet their countries energy demands. The reasons behind this are many, ranging from reducing emissions to the safety of nuclear reactors and waste. For countries lying on or near fault lines, such as Taiwan, the latter becomes an even greater concern. When the earth shakes nuclear power plants, in particular, are highly sensitive and susceptible pieces of infrastructure. To avoid potential catastrophe and achieve greener energy sources the current government in Taiwan is aiming to phase out nuclear power in the coming years and they have chosen wind power as the technology to replace a large portion of the energy supply.<br/> In Taiwan the plan to phase of nuclear power and replace it with wind power has one extra challenge. The plan is not to build on land, like the majority of wind turbine projects, but rather to head out to sea. Offshore wind farms (OWF) are becoming a larger part of the wind power market and European countries have mostly been the early adopters. The waters off Taiwan, in the Taiwan Strait, are attractive for offshore wind farming development due to the favourable wind patterns that occur there. This has drawn major interest from European companies and others around the world to place bids on the growing number of wind farming projects. However, before any of these projects can take place an extensive effort to understand more about the environments below the surface must first be completed.<br/>Fortunately for those individuals who are curious as to the make-up and appearance of the ocean floor, such as engineers who plan to construct permanent structures in the depths, many techniques to map the seabed have been developed. Dr Gwo-Shyh Song, from The Institute of Oceanography at The National Taiwan University, in Taipei, is one local researcher who is very familiar with these methods. "I have been working on seafloor mapping around the Taiwan Island for last 20 years," points out Song. "This includes geophysical surveys, reservoir siltation surveys, cable and pipeline route surveys using a variety of techniques like multi-beam sounders and side-scan sonar as well as chirp sub-bottom profilers." When the offshore wind farming initiative needed experienced local researchers, he was one of a few people with the prerequisite expertise and technical skill required. "In 2012, when the OWF project was set into action and promoted by the Taiwanese Government, myself and my graduated students now employed within Global Aqua Survey Ltd started to become involved with many related investigatory projects," he explains.

The meteorological mast (met mast) for the Taiwan Power Company’s offshore wind farm is located in Taiwan Strait near Changhua County. The p–y curve method recommended in the current offshore foundation design codes does not account for the local scour around the pile foundation; it overestimates the lateral pile deformation and underestimates the foundation stiffness. This paper presents a method to correct the initial modulus of subgrade reaction and modify the ultimate lateral resistance caused by the local scour. The natural frequency of the met mast structure is also determined by a numerical model and verified with the measured data in situ. A comprehensive parameter study is performed to analyze the effect of scour on the dynamic responses of the met mast. Two types of foundation model, a coupled-springs foundation model and a distributed-springs foundation model, are considered in the dynamic analysis of the met mast. The results demonstrate that using a distributed-springs foundation model provides a relatively accurate estimate of the natural frequencies of the met mast structure. Furthermore, the scour exerted significant effects on certain modes of the vibration responses. The natural frequencies of the met mast structure can be reduced by approximately 14% due to scour, particularly in the horizontal bending modes. This paper also provides a preliminary strategy for structural monitoring and analysis to detect scour damage on offshore wind turbines with monopile foundations.