| Title | The Þeistareykir Geothermal Power Station: Improved Efficiency for Electricity Generation with the Addition of a Topping Unit |
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| Authors | Guðmundsson, S.Ó., Einarsson, H.M., Knútsson, V., Gíslason, K.S., Hjartarson, H., Vésteinsdóttir, H |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Landsvirkjun, operates Þeistareykir geothermal power plant, which has two 45 MWe condensing steam turbines. The power plant currently utilizes steam from 12 wells. Due to high silica concentrations in the geothermal fluid, many wells are operated at well-head pressures significantly higher than what the existing steam gathering system, separators, and turbines are designed for. This excess pressure is simply dissipated using orifice plates. The Topping Unit project was established to recover this unused energy and improve overall plant efficiency without increasing steam extraction, thereby making better use of the existing geothermal resources in the area. The concept introduces a high-pressure steam gathering network, a large separator, and a back-pressure turbine in a dedicated powerhouse. The exhaust steam from the Topping Unit feeds directly into the existing system, allowing seamless integration with the condensing units. In the initial design phase, it was estimated that the topping Unit could increase generating capacity by up to 25 MWe without impacting current turbine output. Since it utilizes existing steam, the project requires no new wells and has minimal environmental impact. The unit is also being designed with black-start and island-mode capabilities, enhancing regional grid resilience. The project exemplifies Landsvirkjun’s commitment to maximizing efficiency, reducing emissions, and optimizing the area already used for power production and other infrastructure. It is also an innovative way of better usage of natural resources at site. It is part of a broader development strategy at Þeistareykir, where the plan is to expand the power plant at Þeistareykir even further. |