Development of geothermal energy use

Geothermal energy has been used for thousands of years in many civilisations. It reached a high degree of sophistication in the Roman world. Combined with the formidable water engineering experience of the Romans, it was used extensively for heating and thermal baths. Many of these thermal baths are still in existence, and some are even still in use. The world’s first geothermal power plant was built on a site used by the Romans for thermal bathing over two thousand years ago, and before them by the Etruscans, nearly three thousand years ago.

Modern commercial use of geothermal energy started in the early part of the 19th Century. Geothermal fluids were already being exploited for their energy content. A chemical industry was set up in the zone known today as Larderello in Italy to extract boric acid from the hot waters issuing naturally or from shallow boreholes. The boric acid was obtained by evaporating the hot fluids in iron boilers, using wood from nearby forests as fuel. In 1827, Francesco Larderel, founder of this industry, developed a system for using the heat of the boric fluids in the evaporation process, rather than burning wood from the rapidly depleting forests. Exploitation of the natural steam for its mechanical energy began at the same time. The geothermal steam was used to raise liquids in primitive gas lifts and later in reciprocating and centrifugal pumps and winches, which were used in drilling activity or in the local boric acid industry. The first successful commercial project for generating electricity from geothermal steam was completed in Larderello, Italy in 1904. A 250 kW geothermal power plant began operating there in 1913, and commercial delivery of geothermal electricity to nearby cities started in 1914. By 1942, installed geo-electric capacity had reached 127 MW. The first commercial geothermal power plant using a liquid dominated, hot water reservoir started operation in 1958 in Wairakei, New Zealand. Geothermal electricity production in the United States started in 1960. Today, the US leads the world in geothermal power with over 3 GW of installed capacity.