Of the bacterial isolates found in the Arctic that are able to degrade PCBs, none used compounds such as 2-chlorobiphenyl, 3-chlorobiphenyl, camphor, citronellol, cymene, dehydroabietic acid, limonene, methanol, n-hexadecane, pentachlorophenol, phenol, or pinene as primary growth substrates (Master and Mohn 1998).
In the 20th century, demand for electricity led to the consideration of geothermal power as a generating source. Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904, at the same Larderello dry steam field where geothermal acid extraction began. It successfully lit four light bulbs. Later, in 1911, the world's first commercial geothermal power plant was built there.
In 1800, Italian inventor Alessandro Volta developed the first practical method of generating electricity, the voltaic pile. Made of alternating discs of zinc and copper â interspersed with layers of cardboards soaked in salt water â the pile conducted electricity when a copper wire was connected at either end.