Sustainable Energy Technologies - Concise Summary

Objectives

  • Understand various sustainable energies:
    • Geothermal Energy
    • Biomass
    • Ocean Energy
    • Hydrogen Fuel Cells

Fuel Cells

  • Production: Generates electricity via chemical reaction without combustion, using hydrogen to produce electricity, water, and heat.
  • Structure: Consists of two electrodes - an anode (negative) and cathode (positive) with an electrolyte in between.
  • Principle: Functions like a battery but does not need recharging; hydrogen ions move from anode to cathode creating electricity.
Advantages of Fuel Cells
  • No moving parts and produces no harmful emissions.
  • Requires little maintenance.
Types of Fuel Cells
  • Proton Exchange Membrane Fuel Cell (PEMFC)
  • Solid Oxide Fuel Cell (SOFC)
  • Molten Carbonate Fuel Cell (MCFC)
  • Phosphoric Acid Fuel Cell (PAFC)
  • Direct Methanol Fuel Cell (DMFC)
Applications of Fuel Cells
  • Used in vehicles (buses, cars), trains, ships, and stationary power generation (100KW – 400KW range).

Geothermal Energy

  • Source: Heat from beneath Earth's surface.
  • Methods:
    1. Heating water in a boiler to make steam for power generation.
    2. Direct heating for buildings.
Disadvantages
  • Risks of water depletion, earthquakes, and heat depletion in geothermal areas.

Marine Energy

  • Development through devices such as:
    • Wave power converters
    • Tidal turbines
    • In-stream turbines in rivers
    • Ocean current turbines
    • Ocean Thermal Energy Converters (OTEC)
Wave Power Converter
  • Harnesses energy from wind-generated waves and tides.
  • Can bend waves into channels to increase power for electricity generation.
Tidal Turbines
  • Generates electricity as tide flows in and out, spinning turbines.
In-stream Turbines
  • Utilizes kinetic energy from moving water to generate electricity.
Ocean Current Turbines
  • Exploits movement of ocean water; estimated to generate 8,000 to 80,000 TWh yearly.
Ocean Thermal Energy Converter (OTEC)
  • Utilizes temperature differences between warm surface water and cold deep water to generate electricity and desalinate water.

Biomass

  • Definition: Organic material from living organisms (plants and animals).
  • Energy Source: Derived from sunlight via photosynthesis, transforming carbon dioxide and water into energy.
Utilization
  • Can be burned for heat, converted into electricity, or processed into biofuels.
  • Provides direct and indirect means of transforming energy for use.