Sources of Electricity and Batteries

Sources of Electricity

  • Biomass
  • Wind
  • Hydroelectric
  • Nuclear
  • Solar
  • Natural Gas

Week Objectives

  • Explain how electricity can be produced or acquired.
  • Explain how conventional batteries operate.
  • Explain various types of batteries available in the market.
  • Explain how other sources of electricity can be obtained (fossil, solar, hydro, biomass).

Basic Sources of Electricity

  • Chemical Action: Via batteries.
  • Light: Harnessed from solar energy.
  • Heat: Generated from coal, natural gas, and nuclear sources.
  • Pressure: Resulting from hydro and wind energy.
  • Magnetism: Used in dynamo systems.

Battery History

  • Luigi Galvani (1790): Discovered that frog legs twitched when exposed to electric current.
  • Alessandro Volta: Invented the electric cell by using chemical reactions between different metals to generate electricity.

Types of Batteries

Primary Battery
  • Converts chemical energy directly to electrical energy.
  • Cannot be recharged after the energy is depleted.
Secondary Battery
  • Can be recharged after delivering its energy.
  • Commonly known as storage batteries.

The Electric Battery

  • Components:
    • Electrodes: Two different metals (e.g., zinc and carbon).
    • Electrolyte: A solution, often diluted acid (e.g., sulfuric acid).
  • A simple battery creates a chemical reaction that leads to electron flow, generating electricity.

Carbon-Zinc Dry Cell

  • A low-cost primary cell type.
  • Known as Leclanche cell.
  • Designed for operation at 70°F.

AA Alkaline Cell

  • Anode: Manganese Dioxide
  • Cathode: Zinc Powder
  • Electrolyte: Caustic Alkali
  • Provides extended service compared to other types.

Mercury Cell

  • Common in miniature applications.
  • More expensive and generates higher current.

Lithium Cell

  • Known for high output voltage and long shelf life.
  • Provides approximately 3 V output.

Silver Oxide Cell

  • Uses amalgamated zinc anode and silver oxide cathode.
  • Commonly used in watches.

Secondary Cells

  • Can be recharged, making them reversible in chemical action.
  • The lead-acid cell is the most common type.

Electricity from Fossil Fuels

  • Produced by heating water, creating steam that spins turbines.
  • Example: Kingston Fossil Plant generates 10 billion kWh annually.

Solar Power

  • Involves various methods to harness sunlight for energy.
  • Photovoltaic (PV) cells convert light directly into electricity.
    • Basic Process of PV cells:
      • Light absorption frees electrons.
      • Flow of these electrons creates current.

Hydroelectric Power

  • Utilizes water's gravitational force to generate electricity.
  • Key components of a hydropower plant:
    • Dam: Raises water level, controls flow.
    • Turbine: Converts kinetic energy of water to mechanical energy.
    • Generator: Converts mechanical to electrical energy.
    • Transmission lines: Deliver electricity to end users.

Biomass Energy

  • Biomass refers to organic matter that captures energy through photosynthesis.
  • Common biomass fuels include wood, agricultural residues, and municipal waste.
  • Generally considered carbon-neutral as biomass emissions are part of a natural cycle.

Methods to Convert Biomass to Energy

  • Thermal: Burning biomass to generate steam for electricity.
  • Thermochemical: Heating biomass to produce fuel gases.
  • Biochemical: Fermenting biomass to create alcohol or methane.

Benefits of Biomass

  • Carbon lean, locally sourced, environmentally friendly.
  • Supports rural economies and offers opportunities for local businesses.