AC/DC

 

In 1891 during the International Electrotechnical Exhibition in Frankfurt am Mein he put into operation a 175 km line transmitting 20 kV current with a then unusual efficiency of 75%! Energy transmitted from the hydroelectric power plant in Lauffen (also designed by a Pole) supplied 1000 bulbs, a water pump operating a 20 ft (6 m) tall fountain – an artificial waterfall and the world’s largest electric motor of that time with 100 horsepower.

 

The success of exhibiting the possible applications of alternating current put an end to the nearly ten-year-long dispute between supporters of direct current and protagonists of alternating current, which is historically known as the War of the Currents. According to some commentators, Edison’s failure was due to his insufficient mathematical knowledge. He was certainly an efficient organizer and manager – under his command Menlo Park “produced” more than 1000 patents – but he was not able to manage the complex number calculations that were necessary to understand the theory of construction of an AC generator. Currently – at the beginning of the 21st century – Tesla’s victory is symbolized by  the decline of a classic light bulb – being the flagship invention of Edison – whereas, nearly every electrical device makes use of a patent by Tesla. Considering that there were nearly ten times fewer than Edison’s, it proves the genius of their author.

 

 

On 15 April 1900 the opening of the World Fair – Exposition Universelle – was celebrated in France to commemorate the beginning of a new century. The exposition attracted over 76 thousand exhibitors and more than 50 million visitors. The exhibition grounds covered an area of 1.12 km2 in the Champ de Mars in the centre of Paris and many buildings – now landmarks of the capital city of France – were left over.

 

The 20th century world was already powered with new energy – electric current! Thanks to discoveries and inventions made in the past two centuries electricity could have versatile applications. Hydroelectric and coal-fired power plants, transmission and distribution systems and factories mass-producing electrical equipment had successfully operated for more than a decade. The age of great discoveries in the field of electricity was nearly over – the following years brought far-reaching developments. Outstanding inventors were replaced by engineers – craftsmen working to popularise and improve electrical receivers and power engineering infrastructure.

 

As early as the 19th century, there was a trend to reduce the size of electric motors, which made it possible to design small, convenient to use equipment (e.g. a fan patented by Westinghouse Company), and the previous discoveries by Tesla, Hertz and Marconi resulted in the prototypes of radio communication equipment.

 

In the 1930s electricity was already extensively used in cities. It was worse in rural areas but the governments undertook efforts towards universal electrification. Regardless of the political orientation – be it the “Communism = the power of the soviets + electrification” in the Soviet Union or the Rural Electrification Act in the United States – the result should be similar: universal access to electricity and related benefits. The electrical power engineering industry had to keep pace with the growing consumer market – new solutions were put into use, and more and more power was generated and transmitted. The maximum voltage of a transmission line was 60 kV in 1900. In 1914, it was already 150 kV, and in 1936 a 428-kilometre-long 287 kV line was put into operation to transmit power generated by the first three generators on the Hoover Dam (Boulder). 

 

The world needs more and more power and in the face of climatic changes we cannot afford to increase the number of conventional coal-fired power plants. Experts are in agreement about the directions for the development of the power industry: increasing the share of renewable energy sources in power generation, reducing CO2 emissions and looking for new, “clean” technologies. The world of power engineering has never been short of brilliant minds and it is perhaps they who, aided by resources available in the 21st century, will soon present new solutions that will ensure a sufficient energy supply enabling us to maintain our current living standards while minimizing the negative impact on the natural environment.