Introduction
The late 19th century was an exciting time for electricity and power transmission. On one side, Thomas Edison championed direct current (DC) as the ideal way to distribute electricity. On the other side, Nikola Tesla advocated for alternating current (AC). This battle for establishing the primary method of transmitting electricity became known as the war of currents.
Edison and his Edison Electric Light Company had built the first DC power station in New York City in 1882. At the time, DC was the established method of power transmission. But Tesla believed that AC had key advantages over DC that would make it the superior technology in the long run. This turned out to be true, as AC eventually triumphed over DC.
Edison's Direct Current System
Thomas Edison is often credited with inventing the first commercial power station and electricity distribution system. In the 1870s and 1880s, Edison focused intently on developing a complete DC electrical system, including generators, transmission lines, light bulbs, and motors.
Key components of Edison's DC system included:
- DC generators to produce direct current electricity
- Distribution wires to deliver DC power
- DC motors to convert electric power into mechanical energy
- Incandescent light bulbs that ran on DC
- Fuses and switches for safety and control
In his Pearl Street Station in New York City, Edison demonstrated the first electrical power station that could deliver electricity to paying customers. His DC system worked well for small distances of around one mile from the generating station.
Advantages of direct current:
- Simple and established technology at the time
- Could be directly used with Edison's existing inventions, including light bulbs
Disadvantages of direct current:
- DC voltages can not be increased for long distance transmission without large losses due to resistance of wires
- Required power stations every mile due to low transmission capability
- Dangerous high DC voltages required for long distances
Tesla's Alternating Current Breakthrough
Nikola Tesla was one of Edison's brightest employees and worked closely with him during the early 1880s. However, Tesla dreamed of finding an alternative to Edison's DC system. He focused intently on AC as a solution, carrying out experiments and receiving key patents for AC devices.
Tesla's AC system relied on:
- AC generators to produce alternating current
- Transformers to increase or decrease AC voltages
- Transmission lines for delivering AC electricity
- Motors, lights, and equipment designed for AC
In a brilliant advance, Tesla developed the polyphase AC system that could deliver massive amounts of power efficiently over long distances by using multiple AC currents slightly out of phase from each other. This allowed him to leapfrog Edison's DC system.
Advantages of alternating current:
- AC voltages can be easily increased or decreased using transformers, minimizing power losses across long distances
- Allowed electricity transmission for hundreds of miles from generating station
- Polyphase AC provided an elegant solution for transmitting huge amounts of power
Disadvantages of alternating current:
- Seen as a new, experimental technology compared to established DC at the time
- Required adoption of unfamiliar AC motors, lights, and equipment
Battling for Market Dominance
Edison and Tesla now went head-to-head in the "war of currents" to determine which system would dominate the future of electric power in America. Their business interests became bitter rivals.
Edison's Smear Campaign
Edison launched a smear campaign against the dangers of AC power. He demonstrated its lethal potential by publicly electrocuting animals using AC. He even promoted the development of the electric chair using AC current as a scare tactic against "the dangers of alternating current."
Tesla's Technical Savvy
Tesla won key projects using his polyphase AC system that outmatched DC technology. His Niagara Falls hydroelectric project in 1895 proved AC's viability for massive, efficient power transmission over long distances. Along with demonstration projects showcasing AC motors, lights, and equipment, Tesla gained technical credibility.
Westinghouse Backs AC
The Westinghouse Corporation, led by George Westinghouse, saw the superiority of Tesla's AC approach and acquired his patents. Westinghouse threw his company's resources behind AC, allowing it to go head-to-head with Edison's DC system nationwide.
AC Wins the War of Currents
In the end, AC proved superior for efficient, long distance transmission of bulk electric power. Advantages of Tesla and Westinghouse's polyphase AC system include:
- Transformers allowing extreme voltage increases with minimal power losses
- Capability to transmit electricity hundreds of miles from generating plants
- Scalability to deliver massive amounts of electricity
- Improved motors, lights, appliances running directly on AC power
TheNiagara Falls project marked AC's transition from promising technology to established winner. Within years, AC became the standard for generating stations, transmission infrastructure, and electricity distribution across homes and businesses.
Although DC systems persisted in some urban areas for years, AC became the clear victor by the late 1890s. Edison's smear campaign failed in the face of AC's proven technical and economic superiority.
Legacy of the War of Currents
The war of currents between Edison's DC system and Tesla's polyphase AC ultimately determined how power grids operate around the world. Some key legacies include:
- AC power systems became the universal standard for efficient, large-scale electricity transmission
- AC enabled nationwide electrification and modern electric utilities
- Polyphase AC allowed construction of massive hydroelectric dams
- AC motors drove productivity gains in factories of the early 20th century
- Alternating current still powers homes, businesses, and industries worldwide
Although AC won the 19th century battle of currents, modern high voltage DC transmission still fills an important role in specialized projects. Nevertheless, Tesla's polyphase AC invention remains core to all modern electric grids transmitting vast amounts of power nationwide.
The war of currents shaped the path of electrification and productivity gains worldwide. Both inventors helped usher in the electric age, but Tesla's AC proved most transformational for delivering unlimited energy anywhere.