Economic calculation is the main subject have to be concerned after resource evaluation. Many aspects are calculated in order to provide wether a geothermal prospeck area is promising to be developed. Once a plant is operating it can generate electricity for 25 years or longer if the field is engineered and maintained sustainably. There are some aspects will be calculate such as financial evaluation and operation revenue. While sensitivity analysis is also calculated in order to provide some parameter that effect to geothermal project. All this parameter is following the regulation from government included the unit price that maybe different in Indonesia area.
Financial evaluation could be asses using project cash flow which includes capital expenditure cost, operating revenues, and operating expenses. The operating expense includes maintenance cost, make up well drilling, overhaul, depreciation, and income tax.
Operating revenue includes revenue of power sales, right of exploration/exploitation, production royalty, and production bonus. Operating expense which include fixed and variable maintenance costs, make-up well drilling, and overhauls as well as depreciation and income tax.
Sensitivity analysis is carried out on several parameters that affect the value of the project (in the form of NPV) with a Low and High parameter value.