Unit2

Introduction

  • Established under Section 2(f) of the UGC Act, 1956.

  • Approved by AICTE, COA, and BCI, New Delhi.

  • Focus on Electrical Power Generation and Transmission.

History of Hydro Power Generation

  • 1831: Invention of the first electric generator by Michael Faraday.

  • 1878: Learning to generate electricity using hydropower.

  • 1882: The first hydroelectric power plant began generating electricity in Appleton, Wisconsin, with an output of 12.5 kW.

  • Rapid development of hydro plants occurred in the late 19th century.

  • 1936: Opening of Hoover Dam, producing 1345 MW (later increased to 2080 MW) from the Colorado River.

  • India ranks as the 7th largest producer of hydroelectric power with a capacity of 46,000 MW (12.3% of its total power generation) as of March 31, 2020.

  • Early plants in India: Darjeeling (1898) and Shivanasamudra (1902).

Site Selection for Hydro Power Plants

Key Considerations

  1. Availability of Water: Assess rainfall and runoff data.

  2. Water Storage Capacity & Hydraulic Head: Ensure adequate water storage and pressure for consistent power generation.

  3. Site Access: Sites should be accessible by road and transport.

  4. Distance from Load Center: Minimize maintenance costs by situating near demand areas.

  5. Environmental Effects: Consider local ecosystem impacts and measures to mitigate pollution.

  6. Social Impact: Account for local communities affected by reservoirs; provide for rehabilitation if necessary.

General Arrangement & Operation of Hydro Power Plants

Major Components

  1. Dam/Reservoir: Stores significant quantities of water to generate hydraulic head.

    • Types of Dams:

      • Solid Gravity Dam: Uses weight to resist water pressure.

      • Arch Dam: Suited for high structures with less foundation area.

      • Earth Dam: Economical to construct, but prone to erosion.

  2. Penstock: Steel conduit that carries water to turbines, varies in pressure and thickness.

  3. Surge Tank: Absorbs sudden pressure changes, minimizing water hammer effects.

  4. Power House: Contains turbine, generator, and control gear.

  5. Tail Race: Area where water exits after passing through the turbine.

Operation

  • Water flows under pressure through the penstock, turning the turbine to generate electricity, which is then converted to AC power for transmission.

  • Surge tanks mitigate pressure fluctuations to ensure smooth operation.

Classification of Hydroelectric Power Stations

  1. Run-off River Plants without Pondage: Direct use of river water, low firm capacity.

  2. Run-off River Plants with Pondage: Improved firm capacity with some storage.

  3. Reservoir Plants: Water held behind dams, allowing year-round generation.

  4. Base Load Plants: Operate regularly under consistent demand.

  5. Peak Load Plants: Function during peak demand; can utilize reservoir plants or run-off river plants with pondage.

  6. Pumped Storage Plants: Use off-peak energy to pump water to a higher reservoir for later power generation.

Small Hydro Plants

  • Focus on local community needs, typically with a capacity of 1 to 20 MW.

  • Less than 10-30 MW globally; mini hydro (100-1000 kW) and micro hydro (5-100 kW) definitions vary.

  • Lower environmental impact than large plants.

Merits & Demerits of Hydro Power

Merits

  1. Established technology with low operating costs.

  2. Non-polluting energy source.

  3. Capable of bulk power generation.

  4. Cost-effective electricity production.

Demerits

  1. Requires significant land areas.

  2. Large-scale displacement of communities.

  3. Disruption to aquatic ecosystems.

  4. Environmental disturbance surrounding construction sites.

Introduction to Wind Power Technology

  • Wind is generated by uneven solar heating of the Earth's surface.

  • Wind farms consist of interconnected turbines, with onshore being cheaper and offshore being more stable.

  • China, US, Germany, India, and Spain lead global wind power generation.

General Arrangement & Operation of Wind Power Systems

Major Components

  1. Turbine: Converts wind energy into mechanical energy.

  2. Gearing System: Translates mechanical energy to generator.

  3. Generator: Creates electrical energy from mechanical input.

  4. Control System: Manages turbine orientation and performance.

Wind Power Characteristics

  • Maximum output at wind speeds of 5-12 m/s; safety measures activate at cut-out speeds.

Site Selection for Wind Farms

  • Avoid obstructions, seek elevated locations, ensure soil supports heavy equipment, and maintain good road access for maintenance.

Advantages and Disadvantages of Wind Power

Advantages

  1. No fuel costs.

  2. Potential for decentralized generation.

  3. No direct pollution.

  4. Low electricity generation cost.

Disadvantages

  1. Intermittent energy source reliant on wind availability.

Introduction to Solar Energy

  • The sun produces energy via nuclear fusion, emitting in the visible and infrared ranges.

  • Technologies harness solar energy through photovoltaic (PV) systems, converting sunlight directly to electricity.

Solar PV Cell Technology

  • Photovoltaic Effect: Light energy excites electrons in solar cells, producing voltage.

  • Cells are grouped into modules and panels for greater capacity.

  • Materials include silicon, germanium, and cadmium telluride, among others.

Types of Photovoltaic Cells

  1. Monocrystalline Cells: Highest efficiency (15-20%), expensive, and space-efficient.

  2. Polycrystalline Cells: Cost-effective but lower efficiency (13-16%).

  3. Thin-Film Cells: Less efficient, generally not suitable for residential use.

Solar Energy Systems Overview

  • Off-grid, grid-connected, and hybrid solar systems exist with various advantages and disadvantages.

Thermal Power Generation Overview

  • Dominant power source in India using coal as primary fuel.

  • Components include handling, pulverizing plants, and various boiler types.

Working Principle

  • Water heats to steam in boilers, driving turbines connected to generators for electricity generation.

Major Components of Thermal Power Plants

  • Coal handling, pulverizing, boiler systems, steam turbines, condensers, and cooling towers all play critical roles.

Waste Management

  • Ash handling and water management systems are integral to operational efficiency and environmental impact control.