Challenges in the Geothermal Industry
Geothermal resources are naturally aggressive environments due to inherent high temperature conditions and scaling effects of the geothermal fluids, posing a major threat to the integrity of various components of power plants. The geothermal fluids often contain high proportions of components like carbonates, silicates, sulphates and chlorides, causing extensive surface damage via corrosion, erosion and scaling mechanisms. These damage mechanisms can vary widely based on the thermomechanical properties of the geothermal fluid as well as on the design of the plant components including material selection and dimensions.
Solutions to materials challenges in geothermal
Conscious material selection to minimise the damage mechanism can therefore help in enhancing the reliability of geothermal power plants — increasing the production efficiency, longevity and reduced downtime through failures and/or maintenance and inspection.
“Materials science has a big role to play in addressing some of the challenges, in the geothermal industry. New coatings and materials selection can help addressing the challenges associated in energy production and lowering of overall cost”, says Henry Begg, Section manager, Materials and Surface Engineering, at a recent stakeholder workshop on ‘Geothermal: challenges and opportunities’ hosted at TWI.
“Within the Geo-Coat project, we are aiming at developing novel high-entropy alloys and cermet materials, deposited in coating form to enhance the lifetime of geothermal power plant components suffering from different forms of damage”, says Francesco Fanicchia, Senior Project Leader and coordinator of project Geo-Coat. “The developed coatings show remarkable improvements in terms of lab-based corrosion, erosion and cost performance compared to state-of-the-art alloys and we are currently testing the coatings in-situ within geothermal power plants in order to prove their efficiency further. We expect the project to provide new materials to help geothermal power plant operators to reduce both operational and capital investment through initial material cost reduction and reduced production downtime.”