f Green field evaluation approach for geothermal energy

“Geothermal resource assessment for green fields” is the evaluation of the expected<br>potential of supplied geothermal electricity that might become available for exploitation of a<br>given reservoir.<br>The standard technique described (“stored heat method”) takes into account only the heat<br>reserves of the inferred geothermal field, without any consideration of the number of wells<br>and economical feasibility: the permeability of the system is simply not used.<br>This approach could be considered as “step zero”, for obtaining a first, rough approximation<br>of what it is possible to install on a given field, when the available information are very poor<br>and speculative. We will discuss the physical and mathematical basis of the method, and we<br>will present some application at two real cases. We are restricting our analysis only for water<br>dominated systems, both high enthalpy (flash plant) and medium enthalpy (binary<br>plant). Some examples have been chosen as a benchmark of the technique.<br>With the introduction of an high (realistic) value of the abandon temperature, the correction<br>for the cooling effect specific consumption degradation and the effective flash technology a<br>value significantly lower than the standard approach is obtained. We believe this result as a<br>better estimation of the effective industrial capacity that can be supported by a realistic<br>approach in a geothermal project. More detailed benchmarks will be conducted in the future,<br>with a comparison from the effective geothermal field performances and the estimated<br>capacity.