WorldWide Drilling Resource

43 JULY 2021 WorldWide Drilling Resource ® Larderello~Modern Geothermal Power from Ancient Sources Compiled by Editorial Staff, WorldWide Drilling Resource ® Geothermic activity in Italy dates back to ancient times. A third century Roma n military map identifies the Aquas Volaternas, Aque Populanie, and a circular lake , which probably represents the area of numerous hot boric water lakes. Geotherma l activity in the southern Tuscany region was created by the collision of edges of tw o of the earth’s tectonic plates, the European and the African. It is reasonably certai n the greater Larderello region was characterized by massive thermal discharge dat - ing back at least 2300 years, and probably much longer. Larderello, Italy, is a small town built around an industrial park, born to bes t exploit the area’s geothermal energy. It was founded by the Frenchman Francesc o de Larderel, the first person to be interested in using geothermal energy for indus - trial use. He started the first drilling activities in 1832. In 1838, the engineer Manter i drilled a well of ten Tuscan Arm’s Length (about 23 feet) deep and four inche s wide. In 1904, emerging steam was used to turn a small turbine, which, in turn , powered five light bulbs - the first ever demonstration of geothermal electricity gen - eration. In 1911, the Valle del Diavolo (Devil’s Valley) was chosen as the site of wha t would remain the world’s only geothermal power station for almost half a century . The first generation used reciprocating steam engines, which soon failed due t o corrosion problems, after which clean steam was generated in heat exchangers . Development of new technology and materials enabled the heat exchanger to b e dispensed with, and a 250 kWe (kilowatt-electric) power station was put into oper - ation in 1913. By 1940,130 MWe (megawatt electric) was feeding the Italian railwa y system. A tutorial well was drilled in 1956, 2427 feet deep and almost ten inche s wide. It produced about ten tons of fluid per hour at a temperature of 356º F (180ºC). The fluid was 96% steam and 4% incondensable gases. Until 1958, Ital y was the only country where natural steam was used for power generation on a n industrial scale. To create electricity, cold water is pumped down to super hot granite rocks . High-pressure steam, at temperatures over 392ºF (200ºC), is returned, which turns turbines and generates electricity. Larderello is surrounded by dozens of metal pipes used for the transportation of steam to the power station, where it is trans- formed into electric energy. These pipes have slowly become a part of the landscape. Currently, around one million homes are powered by geothermal electricity from Larderello - almost 5000 GWh (gigawatt hours) per year, or 10% of the world’s total geothermal electricity production. Declining steam pressures during the 1970s and 1980s were largely controlled by reinjection of the steam condensate back into the reservoir and also by deeper exploration programs. Deeper exploration for the greater Larderello geothermal field yielded 3D reflection seismic surveys. Small explosive charges, about seven pounds of TNT (explosive trinitrotoluene), were detonated in shallow holes about 39 feet deep; the reflected waves were picked up by a large array of geophones. The returns from several lines of receivers were processed into 3D plots, identifying the most promising deep well targets. The most important finding revealed the reservoir unified at depth with an enormous extent existing below 9842 feet, feeding the entire region of about 248 square miles. Today, with a total explored area of roughly 155 square miles, Larderello con- tains180 wells. There are 32 geothermal power plants with 34 turbines, producing 5 bil- lion kWh (kilowatt-hour) per year, providing about 27% of the energy needs of Tuscany. More deep drilling is planned for outlying areas where no thermal manifestations are seen and in areas characterized by poor thermal gradients caused by the surface infil- tration of cold water. Drilling may lead to an expansion of the geothermal power capacity of the Larderello area. Larderello geothermal power plant. GEO New & Used Tricones PDCs Drag & Claw Bits Drill Collars Bit Tipping Subs & Stabilizers HDD Bits & Reamers DTH Hammer & Bits Custom Fabrication Junk Mills / Fishing Tools Rod Henderson 661-201-6259 Eran Henderson 661-330-0790