The PERFORM study has prepared a new Best Practice guide, with the objective to minimize scaling and corrosion in geothermal plants. The best practice reviews the typical plant designs and materials for geothermal plants, and then introduces possible scaling and corrosion types that can occur in the saline geothermal water (brine). The best practice manual is supplemented with an interactive toolbox that enables geothermal operators and stakeholders to plan future operations, mitigate obstructions, and optimize production/injection procedures in order to ensure maximum energy production. This easy-to-use toolbox is designed for interactive well check, and it is accessible from the Website via a link/app.
Scaling mitigations involves e.g. strict control of dissolved gasses, use of inhibitors or installation of filters. In general, corrosion is a pronounced operational challenge, since most plants are made from non-coated steel with the potential for corroding materials and release of rust debris etc. Such particles will lead to clogging and subsequent pressure build-up in the wells, and the clogging may only be removed by costly work-over operations. It is thus recommended to strictly control corrosion processes and to select corrosion-resistant materials for casing and top-site facilities. Apart from corrosion, the main challenges in operating geothermal plants are (1): failures related to the Electrical Submersible Pump (ESP) and (2): chemistry changes in the geothermal brine composition and accordingly, guidelines to water sampling procedures are presented. Suggestions for translating these chemistry changes into operational actions are also given. The advice about the operational phases includes start-up, operation, shutdown, standstill and well-head and heat exchanger services. For further details on best practice and lessons learned from operations etc., reference is made to the PERFORM WP4 Study Report: ‘Best practice for geothermal plants to minimize scaling and corrosion’. The report is accessible from the menu bar ‘Publications’ on the Website.