JNTU B.Tech IV WIND, SOLAR AND HYBRID ENERGY SYSTEMS Previous Question Paper (December - 2020 - R16)

Wind energy has emerged as a cornerstone of the global transition toward renewable energy, driven by technological advancements and policy support. The global and Indian scenarios are characterized by rapid capacity expansion and a shift toward larger, more efficient turbine technologies.

Global Scenario:

Globally, wind energy is one of the fastest-growing power generation sources. As of recent data, the total installed wind capacity exceeds 900 GW. The growth is dominated by key markets including China, the United States, Germany, India, and Spain. China leads the world in total installed capacity, accounting for nearly 40% of the global share, driven by aggressive government targets for carbon neutrality. The trend is shifting significantly toward offshore wind development, particularly in the North Sea and the Asia-Pacific region, due to higher capacity factors and the ability to install larger turbines (15 MW+).

Indian Scenario:

India holds the fourth-largest installed wind power capacity globally, with over 44 GW of installed capacity. The sector is primarily concentrated in the southern and western states, specifically Tamil Nadu, Gujarat, Maharashtra, Karnataka, and Rajasthan, which possess high wind power density. The Indian wind energy sector has evolved from a feed-in tariff regime to a competitive bidding mechanism, which has significantly reduced the cost of wind power generation.

Key Statistics and Trends:

• Capacity Growth: India has set an ambitious target of reaching 500 GW of non-fossil fuel capacity by 2030, with wind energy playing a vital role.
• Repowering Policy: A significant portion of India's early wind farms are aging. The government is actively promoting the repowering of older, low-capacity turbines with modern, high-capacity machines to maximize energy yield from existing sites.
• Hybrid Systems: There is a strategic move toward Wind-Solar Hybrid projects, which optimize land use and improve grid stability by balancing the complementary generation profiles of wind and solar resources.
• Offshore Potential: India has identified vast potential for offshore wind along the coastlines of Gujarat and Tamil Nadu, with initial projects currently in the planning and development stages to tap into the high-speed coastal winds.

In summary, while the global market is focused on scaling up offshore capacity and integrating large-scale storage, the Indian market is focused on repowering existing assets, scaling up hybrid systems, and initiating the offshore wind journey to meet its long-term energy security and climate goals.

The power available in wind is derived from the kinetic energy of the moving air mass. Consider a stream of air with density ρ (kg/m³) moving at a velocity v (m/s) through a cross-sectional area A (m²).

The mass flow rate of the air, ṁ, is defined as the product of density, area, and velocity:

The kinetic energy (KE) of this mass of air per unit time is equivalent to the power (P) available in the wind. The kinetic energy of a mass m is given by the formula:

Substituting the mass flow rate into the kinetic energy equation to find the power, we get:

From this final expression, it is evident that the power of the wind is directly proportional to the air density (ρ), the cross-sectional area (A), and the cube of the wind speed (v³). Specifically:

• Air Density (ρ): Power increases linearly with the density of the air.
• Cross-sectional Area (A): Power increases linearly with the area swept by the turbine blades.
• Wind Speed (v): Power is proportional to the cube of the wind velocity, meaning even small increases in wind speed result in significant increases in available power.