| Title | Potential of High Enthalpy Geothermal Power Plants to Operate at Variable Load |
|---|---|
| Authors | Freyr Harðarson(), Kristinn Ingason |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Geothermal power plants in Iceland constitute about 30% of the electricity production with installed capacity of about 780 MW, utilizing high enthalpy geothermal fields. The plants are typically operated as baseload while hydro plants provide the necessary variable load. Wind power has been negligible in Iceland, but this is likely to change as the interest in their installation is increasing. Consequently, the demand for dispatchable power generation will increase. The geothermal power plant’s steam turbines can easily adjust the load to accommodate varying production of wind turbines. Variable extraction from the resource is however more difficult and most usually the geothermal fields are operated at a near fixed extraction and excess steam is exhausted to atmosphere when there is a need to decrease the load. Automatic regulation of the wells to reduce extraction induces the risk of increasing the strain on their casings, reducing the lifetime of wells, or that a well quenches. The paper addresses opportunities of variable extraction on the wells and describes efforts that have been done towards varying the extraction. This includes identifying wells with suitable characteristics for varying extraction, applying reduction on a group of wells and the possibility to increase heat production for CHP plants. The ability to vary the extraction rate of the geothermal field would probably be on a slower time scale than the variation in wind power but it would allow the plants to participate in maintaining stability of the electrical grid while limiting the waste of geothermal energy. |