Jawaharlal Nehru Technological University Hyderabad B.Tech IV Year WIND, SOLAR AND HYBRID ENERGY SYSTEMS Previous Question Paper (September - 2020 - R16)

The Weibull distribution is the most widely used statistical model for representing wind speed data because it provides a flexible fit for the skewed, non-normal nature of wind velocity variations over time. It is defined by two primary parameters: the shape parameter (k) and the scale parameter (c).

The probability density function (PDF) of the Weibull distribution is given by:

Where:

• v is the wind speed (m/s).
• k (dimensionless) is the shape parameter, which indicates the breadth of the wind speed distribution. A low k value (e.g., 1.5–2.0) represents highly variable wind, while a high k value (e.g., 3.0) indicates more constant wind speeds.
• c (m/s) is the scale parameter, which is related to the mean wind speed of the site. It indicates the wind speed magnitude; a higher c value suggests a windier site.

The cumulative distribution function (CDF), which represents the probability that the wind speed is less than or equal to a specific value v, is expressed as:

In practice, wind speed data collected from anemometers at a specific site are analyzed to determine these parameters using methods such as the graphical method, maximum likelihood estimation, or the standard deviation method. The resulting Weibull curve is then superimposed over the actual histogram of observed wind speeds. This model is critical for wind energy assessment because it allows engineers to calculate the potential energy output of a wind turbine by integrating the turbine's power curve with the probability density function of the site's wind speeds. By accurately modeling the wind speed distribution, developers can estimate the capacity factor and annual energy production (AEP) of a wind farm with high reliability.

Wind energy has emerged as a significant contributor to the global and Indian energy mix, driven by the need for sustainable, carbon-neutral power generation. The growth trajectory is characterized by rapid technological advancements and supportive policy frameworks.

Global Scenario: Globally, wind energy is one of the fastest-growing renewable energy sources. Key trends include:

• Installed Capacity: The global cumulative wind power capacity has crossed the 900 GW milestone, with major contributions from China, the United States, Germany, India, and Spain.
• Offshore Expansion: There is a significant shift toward offshore wind projects, particularly in Europe and East Asia, due to higher wind speeds and larger turbine capacities compared to onshore sites.
• Technological Evolution: Modern turbines have increased in size, with individual capacities reaching 15 MW or more, leading to improved capacity factors and reduced levelized cost of energy (LCOE).
• Market Dominance: China currently leads the world in terms of total installed capacity, followed by the United States, reflecting massive investments in grid infrastructure and manufacturing supply chains.

Indian Scenario: India has established itself as a major player in the wind energy sector, ranking fourth globally in terms of installed capacity.

• Capacity Growth: India has an installed wind power capacity exceeding 44 GW. The development is primarily concentrated in states with high wind potential, such as Tamil Nadu, Gujarat, Maharashtra, Rajasthan, and Karnataka.
• Policy and Incentives: The transition from feed-in tariffs to competitive bidding (reverse auctions) has been a major driver in lowering costs, though it has also introduced challenges regarding project margins and timelines.
• National Targets: The government has set ambitious targets to reach 500 GW of non-fossil fuel capacity by 2030, with wind energy playing a critical role in balancing the intermittency of solar power through hybrid projects.
• Manufacturing Hub: India possesses a robust domestic manufacturing ecosystem, with several global OEMs establishing production facilities for blades, nacelles, and towers, making the country a net exporter of wind turbine components.
• Future Outlook: The focus is now shifting toward repowering older, less efficient wind farms with modern, high-capacity turbines and the development of the first offshore wind projects off the coasts of Gujarat and Tamil Nadu.

In summary, while the global market is focusing on scaling up offshore capacity and grid integration, India is leveraging its strong manufacturing base and favorable wind corridors to meet its long-term decarbonization goals.