Geothermal - European Renewable Energy Council

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Geothermal CO 2 Geothermal systems are located in areas exhibiting high CO 2 fluxes inherent to the geology of geothermal host structures. In volcanic environments much higher CO 2 fluxes are the rule. Natural generation of CO 2 in geothermal systems For instance, in Italy, in the Central West Tyrrhenian region, large amounts of CO 2 are produced at depth as a consequence of marine carbonate rock metamorphism. During their ascent, gases get trapped in deep seated structures including permeable mesozoic limestones overlain by impervious capping terrains, which become sources of high CO 2 upward flows. For this reason, deep ground waters are enriched in dissolved CO 2 . Metamorphic processes affecting carbonate phyllites can also contribute to CO 2 production from shallow crustal levels at ca 8 km depths and 400-500°C temperatures, higher than those (3-4 km; 200-300°C) of the overlying geothermal reservoir. Larderello Noteworthy is that natural CO 2 production is independent from geothermal exploitation. Actually, surface manifestations, characterised by hot water and steam discharges from springs and fractures, can create an environment hostile to human settlements (Larderello, Yellowstone). Thanks to industrial geothermal exploitation, deep, eventually toxic, geothermal fluids could be channelled, via geothermal wells and collecting lines, to power plants concentrating on a single point (the plant chimney) natural emissions which would otherwise contaminate the surrounding soils and atmosphere over much larger areas. Summing up, geothermal CO 2 emissions are not generated by the industrial exploitation process. CO 2 emission in electricity production Geothermal, natural emission 122 Natural Gas 315 Oil 760 Coal 915 0 100 200 300 400 500 600 700 800 900 1000 CO 2 emission g/kWh 8 EGEC | Geothermal Electricity and Combined Heat & Power
First experiment to produce geothermal power, done in Italy in 1904 by prince Ginori Conti Geothermal electricity history In the early 1900’s, geothermal fluids were already exploited for their energy content. A chemical industry was set up in Italy during that period, in the area known now as Larderello, to extract boric acid from natural hot water outlets or from purposely drilled shallow boreholes. From years 1910 to 1940 the low pressure steam, in that area of Central Tuscany, was utilised to heat industrial and residential buildings and greenhouses. In 1928, Iceland, another pioneer in the utilisation of geothermal energy, began exploiting its abundant geothermal resources (mainly hot waters) for domestic heating. This application, exemplified by Italy, was followed by several countries. In Japan, the first geothermal wells were drilled in 1919 and in 1929 at The Geysers, California, in the USA. In 1958, a small geothermal power plant started operating in New Zealand, in 1959 in Mexico, in 1960 in the USA, and in many other countries the following years. The first attempt to generate electricity from geothermal steam dates back to 1904 at Larderello. The success of this experiment (see illustration) proved the industrial value of geothermal energy and marked the beginning of an exploitation route that was developed significantly since then. Actually, electricity generation at Larderello was a commercial success. By 1942 the installed geothermoelectric capacity had reached 128 MWe. Geothermal Book - Italy. Panorama Larderello - Today EGEC | Geothermal Electricity and Combined Heat & Power 9
Page 1 and 2: European Geothermal Energy Council
Page 3 and 4: Introduction Geothermal manifestati
Page 5 and 6: Dry steam and Flash power plants Dr
Page 7: 10 MW e Ribeira Grande binary unit
Page 11 and 12: Larderello, Italy Larderello, Italy
Page 13 and 14: Svartsengi Power Plant aerial view
Page 15 and 16: Blumau CHP mic attribute, offer att

Geothermal - European Renewable Energy Council

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