Sustainable Utilisation

Geothermal energy is a renewable energy source that can be utilised in a sustainable or excessive manner. Excessive production from a geothermal field can only be maintained for a relatively short time, and can indicate over investment in wells and power plant equipment. After a period of prolonged overuse, a field operator is forced to reduce the production to the level of maximum sustainable use. To avoid excessive production, “Stepwise de- velopment” is initiated.

Stepwise development of geothermal resour- ces is a methodology that takes into con- sideration the individual conditions of each geothermal system, and minimizes the long-term production cost. The cost of drilling is a substantial component both in the ex- ploration and the development of geothermal fields. With the stepwise development method, production from the field is initiated shortly after the first, successful wells have been drilled. The production and response history of the reservoir during the first de- velopment step is used to estimate the size of the next development step. In this way, favorable conditions are achieved for the timing of the investment in relation to the timing of revenue, resulting in lower long-term production costs than could be achieved by developing the field in one step. Merging the stepwise development method, with the concept of sustainable development of geothermal resources, results in an attractive and economical way to utilise geothermal energy resources.

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