M.TECH THESIS DEFENCE OFFSHORE WIND SPEED PREDICTION USING DEEP LEARNING MODELS Under the supervision of Prof. Pradip Swarnakar DEPARTMENT OF SUSTAINABLE ENERGY ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY (IIT) KANPUR, INDIA 1 Contents Introduction Methodology Results Conclusions References 2 Global Scenario for Renewable Energy Installed Capacity (2024): • Total: ~3500 GW (~30% of global electricity). • Solar PV: 1,200 GW | Wind: 950 GW | Hydropower: 1,200 GW. Top Players: • China: Leader in solar, wind, and hydropower. • USA: Rapid growth in wind, solar, and offshore wind. • EU: Aggressive Green Deal targets; offshore wind focus. • India: Fast-growing solar and wind capacity. 3 Global Scenario for Renewable Energy Investments: • $500B+ (2024) focusing on solar PV, wind, and green hydrogen. Future Outlook: • Renewables to contribute 70–80% of electricity by 2050. Challenges: • Grid integration, storage scalability, supply chain bottlenecks, and policy gaps. 4 Indian Scenario for Renewable Energy Installed Capacity: • Total renewable energy capacity: Over 125 GW (as of early 2025). • Solar energy: ~70 GW. • Wind energy: ~45 GW. • Biomass energy: ~10 GW. • Small hydro: ~5 GW. Global Standing: • India ranks 4th globally in wind power and 5th in solar energy. • Among the top renewable energy-producing countries worldwide. 5 Indian Scenario for Renewable Energy Future Prospects: 1. Target 2030: • Achieve 500 GW of non-fossil fuel energy capacity. • Generate 50% of electricity from renewables. 2. Solar Energy Growth: • Focus on large-scale solar parks and floating solar plants. • Expansion of rooftop solar programs to reach 40 GW target. 3. Wind Energy Opportunities: • Offshore wind projects: India’s first offshore wind farm is being planned in Gujarat and then in Tamil Nadu. 6 Wind Energy India is one of the global leaders in wind energy, leveraging its vast coastline and windy regions to meet renewable energy goals. Installed Capacity: • 45 GW of installed onshore wind capacity (as of 2024), making India the 4th largest wind energy producer globally. • Major contributing states: Tamil Nadu, Gujarat, Maharashtra, Karnataka, and Rajasthan. Wind Resource Potential: • Estimated potential of 302 GW at 100m hub height, primarily concentrated in the southern and western states. 7 Wind Energy Future Outlook: 1. 2030 Target: • Achieve 140 GW of wind energy capacity (onshore and offshore combined). • Offshore wind to contribute 30 GW. 2. Technology and Investment: • Increasing use of larger wind turbines and AI for predictive maintenance. • Investment from domestic and international players to scale up offshore projects. 3. Integration with Hydrogen Economy: • Wind energy to play a key role in producing green hydrogen, especially from offshore installations. 8 Offshore Wind Energy Emerging Sector: • India's offshore wind potential is estimated at 70 GW along the coasts of Gujarat and Tamil Nadu with vast coastline of about 7600 kms. Key Projects: • The First Offshore Wind Project (planned in Gujarat) will have a 1 GW capacity, under development by the Ministry of New and Renewable Energy (MNRE). This Photo by Unknown Author is licensed under CC BY-SA 9 Offshore Wind Energy Policy and Initiatives: • National Offshore Wind Energy Policy (2015): Provides guidelines for offshore wind development. • Collaborations with global entities like the International Renewable Energy Agency (IRENA) and European countries. Challenges: This Photo by Unknown Author is licensed under CC BY-SA • High upfront costs and need for advanced technologies. • Lack of infrastructure for offshore grid connectivity. 10 Why Offshore? Higher Wind Speeds: •Offshore wind speeds are generally stronger and more consistent compared to onshore locations, resulting in higher energy generation potential. Large Resource Potential: •Offshore wind offers immense untapped potential, particularly in India, with an estimated capacity of 70 GW within shallow coastal waters. Reduced Land Constraints: •Offshore wind projects avoid the challenges of land acquisition and competing land use that are common with onshore wind farms. Proximity to High Demand Centers: •Coastal areas often have high population density and energy demand. Offshore wind farms can supply power directly to these regions, reducing transmission losses. 11 Why Offshore? Less Visual and Noise Impact: • Offshore installations are far from populated areas, minimizing aesthetic and noise concerns that often arise with onshore wind farms. Scalability: • Offshore projects allow for larger turbines and expansive arrays, which are not feasible onshore due to space and logistical constraints. Support for Energy Transition Goals: • Offshore wind aligns with global and national renewable energy targets, playing a critical role in reducing reliance on fossil fuels and achieving net-zero goals. 12 Facilitating Offshore Wind in India (FOWIND) • It is a project aimed at advancing India's offshore wind energy sector. • This project is funded by the European Union and implemented by a consortium led by the Global Wind Energy Council (GWEC), in collaboration with the Center for Study of Science, Technology and Policy (CSTEP), the World Institute of Sustainable Energy (WISE), DNV GL, and other partners. 13 Facilitating Offshore Wind in India (FOWIND) Key Objectives of FOWIND: 1. Capacity Building: Enhancing the technical and institutional capabilities of stakeholders to plan and implement offshore wind projects. 2. Mapping Offshore Wind Resources: Conducting feasibility studies and wind resource assessments to identify potential offshore wind energy sites. 3. Policy and Regulatory Frameworks: Providing recommendations to support the development of policies and regulations for offshore wind energy. 4. Industry Engagement: Facilitating dialogue and collaboration between Indian and international industry players to share expertise and best practices. 5. Roadmaps and Reports: Publishing roadmaps and technical reports that outline the steps needed to achieve India's offshore wind energy goals. 14 Facilitating Offshore Wind in India (FOWIND) FOWIND identified states are Gujarat and Tamil Nadu. Specifically the sites are near the: • Gulf of Khambhat, off the coast of Gujarat • Gulf of Mannar, off the coast of Tamil Nadu Source: https://gwec.net/members-area-market-intelligence/fowind/ Figure. 1. 15 Facilitating Offshore Wind in India (FOWIND) • This figure is among the zones identified by the First Offshore Wind (FOWIND) initiative. • This particular site, chosen for its potential in wind energy generation, is situated in the Gulf of Khambhat, near the Gujarat coast shown in this figure. • It is around 23 to 40 km seaward from the Pipavav port, showcasing its significant distance into the marine territory off the Gujarat Coast. • Accessibility to the site is primarily through Pipavav and Jaffrabad ports, facilitating the logistical aspect of wind energy exploration. Source: https://gwec.net/members-area-market-intelligence/fowind/ Figure. 2. 16 Facilitating Offshore Wind in India (FOWIND) The LiDAR sensor for offshore wind measurement in Tamil Nadu is located at: •Vembar, Gulf of Mannar, Tuticorin District, Tamil Nadu • Coordinates: Approximately 8°46' N latitude and 78°14' E longitude. This location was chosen based on its proximity to strong and consistent wind flows, shallow waters suitable for foundation installation, and strategic alignment with the proposed offshore wind energy zones. Source: https://gwec.net/members-area-market-intelligence/fowind/ Figure. 3 17 1. To Develop Accurate Wind Speed Forecasting Models: Implement advanced machine learning models, such as LSTM, Bi-LSTM, ConvLSTM, CNN-LSTM, GRU, and CNN, to accurately forecast offshore wind speeds for different hub heights from 80m to 200m. 2. To Reduce Forecasting Errors: Employ robust data preprocessing and feature engineering techniques to minimize uncertainty and variability in wind speed predictions. 3. To Evaluate Model Performance: Compare the performance of various deep learning techniques based on key metrics like R² and Mean Absolute Error (MAE) to determine the most effective approach. Objectives of the study? 4. To Analyze Seasonal and Temporal Patterns: To improve the accuracy of forecasting models, find and include seasonal and temporal trends in wind speed data. 5. To Enhance Data Predictability: By implementing advanced forecasting models and statistical validation techniques, ensuring reliable and accurate insights for decision-making. 6. To Provide Data-Driven Policy Support: Offer actionable recommendations for energy policy development and infrastructure planning based on accurate wind speed forecasts. 18 Methodology Figure. 4. 19 Data Collection • The data collection step for this thesis on offshore wind speed prediction is anchored in the procurement of particular and relevant datasets from the National Institute of Wind Energy (NIWE) website. • The LiDAR (Light Detection And Ranging) sensors are crucial for gathering accurate wind speed data, which is necessary for the development of offshore wind farms. • The dataset utilized encompasses the latest available LiDAR data, spanning from December 2017 to November 2019, thus providing two years worth of wind speed and other meteorological measurements crucial for this research. Offshore Wind LiDAR sensor data for Gujarat coast 20 Data Description • Total Data Points: 1,05,119 • Non-Null Values: 80,132 • Null Values: 105119-80132=24,987 • Time Interval: Data is recorded every 10 minutes, making it a time-series dataset. 21 Handling Missing Data with KNN •KNN Imputation Technique: The missing values were filled using the K-Nearest Neighbors (KNN) algorithm, which identifies the closest neighboring data points based on feature similarity and computes imputed values accordingly. •Feature Dependence: KNN imputation leverages correlations among features in the dataset, ensuring the imputed values align with the underlying patterns and trends. •Improved Data Integrity: By preserving relationships within the data, KNN imputation minimizes the risk of bias and supports robust analysis in the subsequent modeling and forecasting steps. 22 Handling Missing Data with KNN Data with imputation Data without imputation Figure. 5. 23 Data Analysis Observed Data Figure. 6. 24 Data Analysis Observed Data Figure. 7. 25 Data Analysis Average wind speed for different hub heights Figure. 8. Maximum wind speed for different hub heights Figure. 9. 26 Data Analysis Seasonal Decomposition Isolate Seasonal Patterns: It helps to separate the seasonal component from the trend and residuals, making it easier to analyze and understand periodic fluctuations in the data. This isolation allows for clearer insights into how certain events or cycles influence the time series. Improve Model Accuracy: By decomposing a time series into its trend, seasonal, and residual components, we can better capture the underlying structure of the data, leading to more accurate predictions. This is especially important when dealing with data that exhibits strong seasonal effects. Detect Anomalies and Irregularities: Decomposition helps in identifying any unusual patterns or irregularities in the residuals (the "noise" part of the data) that could indicate anomalies, outliers, or other issues that might require further attention or corrective actions. 27 Data Analysis Seasonal Decomposition Figure. 10. 28 Data Analysis Stationary Data Why its important? • Ensures Reliable Modeling: Stationary data has constant statistical properties (mean, variance, and autocorrelation) over time, which are critical for the validity of many time series models. Nonstationary data can lead to unreliable parameter estimates and poor forecasting accuracy. • Prevents Spurious Results: Stationarity eliminates the risk of spurious relationships in time series analysis, ensuring that the results and insights are meaningful and not driven by trends or seasonality inherent in non-stationary data. Figure. 11. Figure. 12. 29 Data Analysis Stationarity Test The Augmented Dickey-Fuller (ADF) test is a statistical test used to check the stationarity of a time series. Specifically, it tests the null hypothesis (H0) that a unit root is present in the data, meaning the series is non-stationary. The alternative hypothesis (Ha) is that the data does not have a unit root and is therefore stationary. Interpreting the ADF Test Results: 1.ADF Statistic: • If the ADF test statistic is a large negative value (more negative than the critical value), you reject the null hypothesis, indicating the series is stationary. • If the ADF statistic is less negative or closer to zero, you fail to reject the null hypothesis, meaning the series is non-stationary. 2.Critical Values: • The test provides critical values at different significance levels (e.g., 1%, 5%, 10%). • For example, at the 1% significance level, if the ADF statistic is below the critical value (e.g., -3.5), the series is stationary at that confidence level. 30 Data Analysis Stationarity Test Heights ADF statistics 80m -18.69892043 100m -18.75923105 120m -23.41153468 140m -22.42263589 160m -23.74581069 180m -23.88461172 Table. 1. The large negative ADF values consistently from 80m to 200m strongly indicate that the 200m observed for heights -23.90481139 wind speed data at these heights is stationary, meaning its statistical properties (mean, variance, and autocorrelation) remain constant over time, making it suitable for reliable modeling and analysis. 31 Deep Learning Models A total of 7 deep learning models were applied. Figure. 13. 32 Deep Learning Models Models Architecture LSTM LSTM layer: 50, Dense layer: 1, epochs = 5, loss = mse BiLSTM Bidirectional layers: 50, Dense layer: 1, epochs = 5, loss = mse GRU GRU Units: 50, Dense layer: 1, epochs = 5, loss = mse Stacked LSTM First layer: 50, Second layer: 50, Dense layer: 1, epochs = 5, loss = mse CNN LSTM Conv1D filters = 64,Max pooling = 2, LSTM = 50, Second Dense layer: 1, epochs = 5, loss = mse ConvLSTM filters = 64, Dense layer: 1, epochs = 5, loss = mse CNN Conv1D filters = 64,Max pooling = 2, First Dense layer = 50, Second Dense layer: 1, epochs = 5, loss = mse Table. 2. Model Architecture 33 Performance Metrics Five distinct performance indicators were employed to examine the accuracy of the applied models. These consist of the R2 value, root mean square error (RMSE), mean square error (MSE), mean absolute percentage error(MAPE) and mean absolute error (MAE). For a dataset with n data points, where yi represents the actual value and yⅈ represents the model’s predicted value. Mean Absolute Error (MAE) = 1 n Σ y − yⅈ n ⅈ=1 ⅈ Mean Squared Error (MSE) = 1 n n Σⅈ=1 yⅈ − yⅈ 2 Root Mean Squared Error (RMSE) = MSE = 1 n Σ y − yⅈ 2 n ⅈ=1 ⅈ Mean Absolute Percentage Error (MAPE) = 1 𝑛 𝑦𝑖 −𝑦𝑖 𝛴 × 100 ⅈ=1 𝑛 𝑦 𝑖 R2 (Coefficient of determination) = 2 Σn ⅈ=1 yⅈ −yⅈ 1-Σn y −y 2 ⅈ ⅈ=1 ⅈ 34 Results For 80m hub height. Height 80m MAE RMSE MAPE R2 LSTM 0.3827 0.5933 10.3933% 0.9479 BiLSTM 0.3144 0.5469 6.9528% 0.9557 GRU 0.3384 0.5598 7.8832% 0.9536 Stacked LSTM 0.2405 0.5176 5.8705% 0.9603 Conv LSTM 0.287 0.5379 6.1254% 0.9572 CNN LSTM 0.5085 0.6864 11.2262% 0.9302 CNN 0.2822 0.5506 6.5395% 0.9551 Models For 80m hub height the Stacked LSTM model performed best amongst all as highlighted above. Table. 3. 35 Results For 80m hub height. Stacked LSTM model Figure. 14. 36 Results For 100m hub height. Height Models MAE RMSE MAPE R2 100m BiLSTM 0.2962 0.5343 6.1817% 0.9587 GRU 0.2657 0.5163 6.6416% 0.9615 Stacked LSTM 0.3267 0.5468 8.5328% 0.9568 Conv LSTM 0.2283 0.5049 5.5282% 0.9631 CNN LSTM 0.2721 0.5395 6.6313% 0.9579 CNN 0.3072 0.5517 6.6746% 0.9560 For 100m hub height the Conv LSTM model performed best amongst all as highlighted above. Table. 4. 37 Results For 100m hub height. Conv LSTM model Figure. 15. 38 Results For 120m hub height. Height Models MAE RMSE MAPE R2 120m LSTM 0.3275 0.5458 6.7361% 0.9581 BiLSTM 0.3359 0.5542 6.3079% 0.9568 GRU 0.2667 0.5183 5.7818% 0.9622 Stacked LSTM 0.2317 0.5150 5.0496% 0.9627 Conv LSTM 0.2345 0.5060 5.5518% 0.9640 CNN LSTM 0.278 0.5469 7.1564% 0.9579 CNN 0.2824 0.5467 6.4987% 0.9580 For 120m hub height the Conv LSTM model performed best amongst all as highlighted above. Table. 5. 39 Results For 120m hub height. Conv LSTM model Figure. 16. 40 Results For 140m hub height. Height Models MAE RMSE MAPE R2 140m LSTM 0.2857 0.5487 6.5994% 0.9584 BiLSTM 0.2444 0.5367 5.4492% 0.9602 GRU 0.2989 0.5513 6.2145% 0.9580 Stacked LSTM 0.2368 0.5372 5.5120% 0.9601 Conv LSTM 0.2925 0.5486 6.5110% 0.9584 CNN LSTM 0.3128 0.5852 8.8687% 0.9527 CNN 0.2744 0.5679 7.0406% 0.9555 For 140m hub height the BiLSTM model performed best amongst all as highlighted above. Table. 6. 41 Results For 140m hub height. BiLSTM model Figure. 17. 42 Results For 160m hub height. Height Models MAE RMSE MAPE R2 160m LSTM 0.2498 0.5358 5.6138% 0.9612 BiLSTM 0.2488 0.5332 5.6189% 0.9616 GRU 0.306 0.5558 5.9047% 0.9583 Stacked LSTM 0.3406 0.5707 7.7336% 0.9560 Conv LSTM 0.257 0.5382 6.1428% 0.9609 CNN LSTM 0.4006 0.6233 7.8882% 0.9475 CNN 0.2904 0.5822 7.9967% 0.9542 For 160m hub height the BiLSTM model performed best amongst all as highlighted above. Table. 7. 43 Results For 160m hub height. BiLSTM model Figure. 18. 44 Results For 180m hub height. Height Models MAE RMSE MAPE R2 180m LSTM 0.3132 0.6184 7.0050% 0.9491 BiLSTM 0.2611 0.6021 5.9011% 0.9517 GRU 0.3249 0.6253 7.0092% 0.9479 Stacked LSTM 0.3011 0.6206 8.1384% 0.9487 Conv LSTM 0.2803 0.6101 6.1625% 0.9504 CNN LSTM 0.4102 0.6728 8.9017% 0.9397 CNN 0.3407 0.6415 9.1412% 0.9452 For 180m hub height the BiLSTM model performed best amongst all as highlighted above. 45 Results For 180m hub height. BiLSTM model Figure. 19. 46 Results For 200m hub height. Height Models MAE RMSE MAPE R2 200m LSTM 0.2807 0.6828 6.3882% 0.9373 BiLSTM 0.2793 0.6835 6.4155% 0.9372 GRU 0.3205 0.6851 7.2951% 0.9369 Stacked LSTM 0.3252 0.7100 7.0801% 0.9322 Conv LSTM 0.3654 0.7099 8.2730% 0.9322 CNN LSTM 0.3468 0.7080 8.3953% 0.9326 CNN 0.3678 0.7258 7.6748% 0.9292 For 200m hub height the LSTM model performed best amongst all as highlighted above. Table. 8. 47 Results For 200m hub height. LSTM model Figure. 20. 48 Conclusions • Forecasting models in offshore wind speed prediction are critical for structural health monitoring of wind turbines, ensuring their durability, optimizing performance, and maintaining the reliability of renewable energy contributions to the grid. • Models such as Stacked LSTM and ConvLSTM demonstrated high accuracy at hub heights between 80m and 120m, with MAPEs ranging from 5.52% to 5.87%, showcasing their ability to effectively capture spatial-temporal wind patterns. • The Bidirectional LSTM model proved robust in handling long-term wind data dependencies, achieving MAPEs between 5.45% and 5.9% at hub heights of 140m, 160m, and 180m. • The LSTM model recorded a relatively higher MAPE of 6.39% at 200m, indicating opportunities for model refinement, potentially through the inclusion of additional atmospheric variables like pressure and temperature. 49 Policy Implications Accurate wind speed forecasting facilitates the identification of high-potential offshore wind sites, enabling optimal resource allocation and enhancing the efficiency of offshore wind energy projects. This aligns with India’s ambitious target of achieving 30 GW offshore wind capacity by 2030. Reliable time series forecasting supports better grid integration, addressing the variability challenges associated with renewable energy sources and ensuring grid stability. The study's results hold the potential to guide investment decisions by reducing risks and uncertainties, thereby encouraging private sector participation. Policymakers can utilize these insights to refine energy planning strategies, reducing reliance on fossil fuels and advancing the nation’s commitment to achieving net-zero emissions by 2070. 50 Policy Implications Moreover, the implications extend to fostering local manufacturing hubs and job creation in coastal regions, strengthening the economic fabric of the country. This research contributes to designing resilient energy systems, capable of adapting to the impacts of climate change, such as shifting wind patterns and rising sea levels. Lastly, the study provides a robust data-driven foundation for refining and implementing policies like the National Offshore Wind Energy Policy, thereby bolstering India’s renewable energy ecosystem. These findings underscore the role of advanced forecasting techniques in shaping a sustainable and energy-secure future for the nation. 51 Limitations of the Study Dependence on Data Quality and Availability: One primary challenge lies in the dependence of the predictive models on the quality and availability of historical wind speed data. In regions where data is sparse, inconsistent, or collected at low resolution, the accuracy and reliability of these models may be compromised. This limitation underscores the importance of robust data collection frameworks and highlights the need for enhanced efforts to fill data gaps in underrepresented regions. Computational Complexity: Another limitation stems from the computational complexity of deep learning models like BiLSTM, ConvLSTM, and CNN-LSTM. These models, while effective, require substantial computational resources, which can pose challenges for real-time applications or deployment in resource-constrained environments. Future research should optimize these models for efficiency without sacrificing accuracy, ensuring they remain scalable and accessible for broader applications, including operational forecasting and policy planning. 52 References [1]“Emissions Gap Report 2023: Broken Record,” Emissions Gap Report 2023: Broken Record. Accessed: Mar. 13, 2024. [Online]. Available: https://www.unep.org/interactives/emissions-gap-report/2023/ [2]“Executive summary – Renewables 2023 – Analysis,” IEA. Accessed: Mar. 13, 2024. [Online]. Available: https://www.iea.org/reports/renewables-2023/executive-summary [3]“Electricity – Renewables 2023 – Analysis,” IEA. Accessed: Mar. 13, 2024. 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Moaveni, “Regularized hidden Markov modeling with applications to wind speed predictions in offshore wind,” Mech. Syst. Signal Process., vol. 211, p. 111229, Apr. 2024, doi: 10.1016/j.ymssp.2024.111229. [10]M. Martinez-Luengo, A. Kolios, and L. Wang, “Structural health monitoring of offshore wind turbines: A review through the Statistical Pattern Recognition Paradigm,” Renew. Sustain. Energy Rev., vol. 64, pp. 91–105, Oct. 2016, doi: 10.1016/j.rser.2016.05.085. [11]“Energies | Free Full-Text | Can LiDARs Replace Meteorological Masts in Wind Energy?” Accessed: Mar. 18, 2024. [Online]. Available: https://www.mdpi.com/1996-1073/12/19/3680 [12]C. B. Hasager et al., “Offshore wind climatology based on synergetic use of Envisat ASAR, ASCAT and QuikSCAT,” Remote Sens. Environ., vol. 156, pp. 247–263, Jan. 2015, doi: 10.1016/j.rse.2014.09.030. 54 THANK YOU!!! 55 56
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