1.2        Short History

Milestones

Hot springs were in use since ancient times for medical, household and recreational purposes. For example the first Polynesian settlers of New Zealand, living undisturbed from the influence of Europeans until the 18^th century, used to harness steam captured from hot springs for cooking, bathing, washing and curing. As a matter of fact the first written records regarding the purposeful use of geothermal energy go back to the Romans. In addition to curing eye and skin diseases, they also utilized hot springs for heating buildings and the thermal water facilities of bath resorts. It is well exemplified by Pompei or the Roman resorts of the British Province, where hot springs were directly exploited through a well-constructed system of pipelines, supplying bath resorts or households with hot water.

The first records of industrial use date back to the 18^th century, when fumaroles - flows of steam from the ground – were observed in Larderello, Toscana. The precipitated steam - cooling in the gorges - formed lagoons from which valuable minerals (sulphur, boron, ion etc.) could be retrieved through distillation. Steam – at the same time being used as a cheap fuel - was driven into a still, enabling manufacturers to extract the minerals at a low cost.

As the spouting fluid was the most important source of boron, geothermal energy in Toscana was used in its natural form to produce boron and ammonia. The presence of heat energy was only of secondary importance, mainly used for heating the stills. The spread of stills however symbolized a significant step in the development of geothermal energy utilization, as it raised the question of how to bring steam to the surface artificially.

Geothermal energy exploited for electricity generation commenced in 1904, when Prince Piero Conti established the first geothermal power plant in Landerello. By 1913 the plant reached a capacity of 250 kW. It is worth mentioning that the plant operates even today. Its current capacity exceeds 400 MW, which is to be further increased with the help of a development program to 880 MW.

Technical developments brought about by the 19^th century and the early part of the 20^th century, as well as the scientific works of such researchers as Kõnigsberger, Bullard, Krige and Benfield allowed for the investigation of hydrothermal potential stored in the deeper strata. Accordingly the exploration of geothermal reservoirs commenced. These early and ambitious investigations were soon to be supported and further intensified by using Rotary drills. Despite the fact that drilling was originally adapted from the oil industry, today it is the most widespread technology used not only for the exploration of oil, but also that of geothermal reservoirs.

As a direct consequence of reservoir discoveries, geothermal energy utilization has experienced high-speed progress right from the beginning of the 1950’s, particularly the reservoirs of the Wairakei region in New Zealand and the Geyser fields of North California. The latter started to produce in 1960 and was soon claimed to be the most dynamically developing region, with a capacity of 2800 MW.