Electricity History

Topics

  • History of Electricity and Magnetism
  • Introduction to electrical models

Learning objectives

  • Appreciate electricity as a modern technology
  • Differentiate between a model and a physical object

Guiding questions

  • What technologies enable our electricity infrastructure?
  • What technologies are available to deliver the services we want?
  • How do we estimate electricity usage and impacts?

First observations of charge

  • Ancient Greeks
  • Rubbed amber and fur
  • Noticed the attraction of lightweight particles

First observations of magnetism

  • Lodestone observations in Greece, India, China.

Electrons

  • What is an electron?
  • We have different models of electrons

Bohr model of the atom

Atomic Orbital Model of the atom

Conductors and Insulators

  • Conductors have electrons that are mobile
  • Insulators have tightly bound electrons

What is magnetism?

Compass

  • Observed as early as 200BC by the Chinese
  • Navigational use in China about 1000 AD

Capacitor

  • Capacitors are capable of storing electric charge
  • Leyden jar invented in 1744 by Ewald Georg von Kleist

Battery

  • Battery can provide current at a steady voltage
  • Demonstrated by Alessandro Volta in 1800 using alternating plates of copper and zinc

Electromagnetism

Electromagnetism

  • The discovery of the relationship between electric current and magnetic fields enabled our modern electricity system.
  • Motion can be transformed into electric currents
  • Electric currents can be transformed into motion

Compass Needle Deflection

  • Observed by Hans Christian Oersted in 1819
  • Realized that electric current flowing through a wire creates a magnetic field around the wire

Ampere’s Law

  • Quantified the relationship between this circulating magnetic field and the current in the wire
  • Andre-Marie Ampere, 1820
  • \oint B \cdot dl = \mu_0 I_{enc}

Electromagnetic Rotation

  • Michael Faraday, 1821

Ohms Law

  • 1827
  • Georg Ohm
  • Ohm’s Law
  • The current through a conductor is directly proportional to the potential difference across the two points.
  • V=IR
  • This will be a model we use frequently

DC Electric Motor

  • Anyos Jedlik
  • 1828
  • commutator

Lenz’s Law

  • 1833
  • An induced electromotive force always gives rise to a current whose magnetic field opposes the original change in magnetic flux

Maxwell’s Laws - 1861

  • \nabla\cdot E = \rho/\epsilon_0
    • Electric field lines begin on charges
  • \nabla\cdot B = 0
    • No magnetic charges
  • \nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}} {\partial t}
    • Changing magnetic field generates an electric field
  • \nabla \times \mathbf{B} = \mu_0\left(\mathbf{J} + \varepsilon_0\frac{\partial \mathbf{E}} {\partial t} \right)
    • Electric current creates a magnetic field

Remnant DC system

  • San Francisco has DC grid to power old elevators

AC Electric Motor

  • Ferraris
  • Nikola Tesla
  • 1885

First Electric Vehicle

Flocken Elektrowagen, First Electric Vehicle, 1888

Pearl Street Station

  • Operated by Edison Electric in 1882 in Manhattan
  • Used a DC Generator and steam engines

AC vs DC current

  • DC championed by Thomas Edison
  • AC championed by George Westinghouse

Transformer

  • 1884 ZBD Transformers

Transition to Widespread Electrification

  • By 1930, 70% of households were electrified
  • Rural Electrification Administration established in 1935

Transistor

  • 1947
  • Bardeen, Brattain, Shockley
  • Enabled the electronics and computer revolution

Lighting

  • 1880’s sees the first commercialization of incandescent light bulbs after years of research
  • Title III of the Energy Independence and Security Act of 2007 effectively bans the use of incandescent light bulbs

Deregulation

  • Electricity monopolies were dismantled
  • California Electricity Crisis 2000-2001

Renewable Portfolio Standards

  • California Assembly Bill 32
  • Mandates reductions in greenhouse gas emissions

Electricity Contribution Environmental Problems

  • Acid Rain
  • Climate Change

Financing Innovations

  • Property Assessed Clean Energy (PACE), 2008
  • Sonoma County had first county-wide program in the nation
  • Solar Lease, Power Purchase Agreement