STUDY ON THE EXPLOITATION POSSIBILITY OF THE THERMA-NIGRITA GEOTHERMAL FIELD (PREFECTURE OF SERRES)

Résumé

The aim of this study is to evaluate the potential of Therma Nigrita low-enthalpy geothermal field and to examine the possibility of exploitation. Six geothermal fluid samples and two cold-water samples were obtained from eight boreholes situated in the Therma field of Nigrita. Field measurements, as well as laboratory determinations using classic and modern methods of analyses were carried out. The temperature of the geothermal fluids ranges from 38,5 up to 62,5°C; the discharge rates of the boreholes range from 40 up to 70 m3/h. These data lead to the conclusion that the field is exploitable. Due to high As and Li contents and in order to avoid environmental impacts, it is essential to reinject the waste geothermal fluids into the geothermal reservoir. For the exploitation of the geothermal field, the applications of district heating and cooling of a part of Nigrita Municipality using heat pumps, in combination with greenhouse applications, are proposed. In order to save energy and reduce the capital cost, the above applications have to be placed in cascade. The energy production cost, including also the capital amortisation cost, of the above application amounts to 0.0226 €/kWh. The proposed geothermal applications have a significant economic advantage over the use of fossil fuels. Additionally, there is an important environmental benefit from avoiding the emission of severe quantities of CO2 (>8,000 tons annually), which would be emitted in case of oil use.