The History of Alternating Current:

The History of Electrification

The power grid started with long distance transmission and soon led to interconnected systems, these are some of the landmark early power generation sites.

1.) Background
2.) List of important early power sites
3.) Sites by geography (interactive maps)

The power grid as we know it began with isolated power generation systems across the world starting in the 1870s. The growth and unification of the systems into an interconnected AC power 'grid' helped raise the quality of life of people from all classes.

Long-Legged Mary Ann type early DC dynamo created and sold by Thomas Edison.

Electric power first saw commercial use in the 1870s. DC systems dominated from the 1870s-1891. The 1891 Electro-Technical Exposition in Frankfurt marked the end of the DC era.


Illustration of a maiden providing electric power from a distance, International Electrical Exhibition Frankfurt 1891

Direct Current Beginnings:

DC power systems dominated in the 1870's and 1880s. "Small" systems were sold to factories around the world, both in urban areas, and remote undeveloped areas for industrial/mining use. Thomas Edison, Charles Brush, and Werner von Siemens lead the industry in DC systems. DC systems powered factories and small downtown areas but did not reach 95% of residents. Electric lighting was a luxury found only in hotels and other businesses as well as in the mansions of people like George Westinghouse and J.P. Morgan.

The first methods used to power both DC and AC generation plants were coal-fired steam engines and hydroelectric power. Since most industrial cities were already located at waterfall/rapids, utilizing traditional mill power it was natural to convert to hydroelectric power. Learn more about methods of power generation on our page here.

Since coal was costly, early business people envisioned sending great power over distance from dams to cities not already blessed with reliable hydro power. To send DC power over distance one needed to use high voltage:

HVDC Power - This was the first method of transmitting electric power over distance. HVDC is the oldest and "newest" method of distance transmission, today it has reemerged in an advanced form to possibly replace major AC high-voltage routes.

Alternating Current

AC Power provided the solution to distance transmission. AC also provided a solution to interconnect generation sites. The development of the 3-phase AC power system in the late 1880s proved the effectiveness of the system and electrification of entire cities and regions began in the 1890s.

More on Alternating Current History >
More on Three Phase Power >

2.) List of important early power stations

Click on the power plants to learn more about them. Some of the pages are Edison Tech Center pages which have photos and videos.


1879: Dolgeville Dynamo This power station built at the Dolgeville Mill in Dolgeville, NY supplied power for industrial purposes.


1881: Niagara Falls, New York -A small dynamo supplied a few stores in in Niagara Falls with power for lighting. AC power came to this area 14 years later.


1882: Appleton Wisconsin, US DC power, 12.5 kW. This was the first Edison hydroelectric station. It powered Van Depoele's early electric trolleys later in 1886.


1882: Miesbach to Munich, Germany- longest DC transmission to this date: 1400 volts 57 km distance built by Marcel Deprez. HVDC
Transmission length: 57 km (37 miles)

1882: New York City- Edison Illuminating Company builds New York's first power plant at the Pearl Street Station. The DC station lit up to 400 lights and served 85 customers at first. The plant grew consistently over the next few years.
Transmission length: several blocks downtown


1884: England - Gaulard and Gibbs build an AC power plant using a rudimentary transformer which allows for voltage to stay constant despite additional lights(load) being added.
Transmission length: unknown


1884: Lanzo Torinese to Turino, Italy- 2000 volt experimental transmission line built for the International Electricity Exhibition. This transmission line uses a Gaulard and Gibbs transformer.
Transmission length: 40 km (25 miles)

1886: Great Barrington, Massachusetts The first full feature AC power distribution system using transformers is built in the small city of Great Barrington. It used a Siemens generator and Edison's incandescent lights. 500 volts.
Transmission length: 4000 ft (1.2 km)

1886: Pittsburgh, PA Oliver Shallenberger, the main engineer of AC power technology at Westinghouse constructs an AC system for Union Switch and Signal Company Works. George Westinghouse was pleased and began to sell this system. It operated at 1000 volts.
Transmission length 3 miles

1887: Buffalo, NY Oliver Shallenberger and William Stanley build the first commercial AC power plant for Westinghouse for Buffalo Electric Company. Single phase. Voltage ?.
Transmission length unknown

1887: Greater London Sebastian de Ferranti builds the largest AC power station to date (10,000 Volts). After business and other problems the Deptford Power Station is forced to delay opening until 1891. The station eventually supplies central London.
Transmission length unknown

1889: Oregon City Falls, Oregon, USA Longest DC transmission of power in North America is established south of Portland at Station A.
Transmission length 14 miles (DC Power)

1890: Oregon City Falls, Oregon, USA Experimental, 2 phase AC generators installed by Westinghouse at Powerhouse A, it sent power to Portland. It was 5 years later before regular commercial AC power was established in Powerhouse B.
Transmission length 14 miles (AC power)

1891: Telluride Colorado- Ames Hydroelectric Plant: 3000V, 133 Hz, single phase. It sent power to mining operations in the mountains near Telluride. It was a Westinghouse experimental project.
Transmission length: 2.5 miles

1891: Lauffen-Frankfurt Germany - A MAJOR STEP FORWARD: The first long-distance and 3-phase alternating current demonstration. This proved that three phase power worked the best for a power grid. This project was developed by Oskar von Miller and engineered by the founder of 3 phase AC power Mikhail Dolivo-Dobrovolsky.
Transmission length 175 km (109 miles)

1893: Redlands Mill Creek 1 powerhouse Redlands, CA 1893
The first 3-phase AC commercial power plant in the world. This used C.P. Steinmetz's improved 3-phase system.
Transmission line length: 7 miles


1893: Hellsjon - Grangesberg, Sweden: developed by Ernst Danielson, he also was involved in the Mill Creek Plant at Redlands, California in the same year. General Electric Company.
Transmission line length: 10 km


1895: Pelzer Hydroelectric Plant, South Carolina This plant provided AC 3-phase power to the Pelzer Manufacturing Plant. 3300 V (no transformers were used on transmission)
Transmission line length: 2.75 miles

1895: Folsom Powerhouse, Folsom California Built near a reservoir that catches water from the Sierra Nevada outside of Sacramento.
Transmission line length: 22 miles

*The Folsom Prison opened a small AC powerhouse in 1893 as part of the same hydro system

1895: Oregon City Falls, Oregon, USA. Powerhouse B is built on the Willamette River and supplies commercial AC power to Portland 14 miles away.
Transmission line length: 14 miles

1895: Niagara Falls AC Power Plants Westinghouse won the contract to build this power plant. GE won the contract for power transmission to Buffalo. The opening of the power plants was trumpeted in the international press more than any other hydro plant before, or possibly since. For this reason it is mistakenly believed to be the first. Nonetheless it was the largest hydro power plant till that date.
Transmission line length: 25 miles (1896)

1897: Mechanicville Power Station, Mechanicville, New York
This power station was built as an experiment of C.P. Steinmetz and commercial operation. Transmission line length: 17 miles
- Also the site of Albert W. Hull's HVDC experiments in 1932 read more about it.


1908: Schaghticoke Power Station Schaghticoke, NY

Site of an experimental monocyclic power transmission 1908. This was a project by AC Pioneer Charles. P. Steinmetz. Various power stations like this became testing grounds for new transmission technologies.

1915: Cohoes Power Plant Cohoes, NY

This plant was a part of the wide scale electric power development going on across the US and Europe at the time. The power grid begins to form as clusters of powerplants begin to interconnect.

After 1900 the number of power stations exploded. All across the world from Argentina to Singapore AC 3 phase power became established as the best way to supply populations with electric power.

3.) Sites by geography

Below: Sites of engineering significance, some of which are early electric power stations.

First transformers and early AC power Advanced mathematics - CP Steinmetz First Induction Coil First battery? Static electricity, first historical mention of electricity Aerospace and automatic control engineering Aerospace and defense technology center The Arc: First Capacitor? Early AC power Supergrid - HVDC from Saharan powerhouse Induction motor and AC power technologies First Battery First HVDC line First long distance AC transmission First powerful dynamo Lighting Technology Neon Lamp Geothermal Power

Connected Pioneers:

Ernst F.W. Alexanderson
- pioneer in wireless and TV transmission

Ernst Julius Berg
- developed two way wireless audio communication. Worked on AC power.

Charles F. Brush
- pioneered Generators, lamps, trolleys and an early profitable industry.

Mikhail O. Dolivo-Dobrovolsky
- pioneer of 3 phase AC power systems

Galileo Ferraris
- Early AC power pioneer. Inventor of the polyphase AC motor.

Oskar von Miller
- early pioneer of AC and HVDC power in Germany

Edwin W. Rice, Jr
- AC power systems pioneer. Leader of the electrical industry.

William Stanley
- inventor of the first modern transformer, heart of the AC power system.

Charles P. Steinmetz
- pioneer of AC power systems, first person to understand AC power mathematically.

Nikola Tesla
- improved upon many technologies, most notably AC power.

Elihu Thomson
- improved DC and AC power systems, arc lights

George Westinghouse
- innovator in many technologies, business leader.

Related Topics:


AC Power History

High Voltage DC Transmission

Power Transmission

Lightning and Surge Arrestors

More Stuff

For a list of sources see each of the individual pages above.
Click on the sites above and they will take you to a source.
The Hawkins Electrical Guide. 1915
The General Electric Story. Hall of History Publications. 2000
Willamette Falls - Where the Future Began. 2013
Alternating Current Development in America. by William Stanley. 1912

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