REFLECT: Redefining geothermal fluid properties at extreme conditions to optimize future geothermal energy extraction

The Enterprise Expert Advice of the Ukrainian Association of Geologists as a Linked Third Party was involved in the three-year project«REFLECT: Redefining geothermal fluid properties at extreme conditions to optimize future geothermal energy extraction».

This project has received funding from the European Union`s Horizon 2020 research and innovation programme under grant agreement no H2020 850626.

Grant agreement ID: : H2020 850626

Starting date of the project: 01.01.2020

Finish of the project: 31.01.2023

Project Description

Creating a common and public Fluid Atlas

The Fluid Atlas will provide information on geothermal fluid properties across Europe. It will be public and available to all geothermal operators and stakeholders.

Reducing maintenance costs

REFLECT will improve predictions of chemical reactions to help operators find solutions for the design of power plants and avoid typical problems causing maintenance costs and downtimes.

Reducing environmental impact

By improving knowledge of free gas formation during fluid production (e.g. greenhouse gas), the destruction of plant materials by corrosion and the formation of radioactive deposits can be avoided.

About the project


The efficiency of geothermal utilisation depends on the behaviour of fluids that transfer heat between the geosphere and the engineered components of a power plant. REFLECT aims to prevent problems related to fluid chemistry rather than treat them. The physical and chemical fluid properties are often poorly defined, as in situ sampling and measurements at extreme conditions are difficult to date. Therefore, large uncertainties in current model predictions prevail, which will be tackled in REFLECT by collecting new, high-quality data in critical areas. These data will be implemented in a European geothermal fluid atlas and in predictive models allowing to provide recommendations on how to best operate geothermal systems for sustainable use.

Results and key stakeholders

Data base

  • Geothermal Industry: operators, consultants
  • Other industry: mining, waste water treatment
  • Enviromental, public: nuclear waste storage
  • Academia: geochemists, physicsts, geologists

Fluid Atlas

  • Geothermal industry: operators, consultants, investors
  • Academia

Fluid sampler

  • Geothermal industry: operators, consultans

Predictive models

  • Geothermal industry: operators, consultans

Project objectives

From react to REFLECT

Our project aims at preventing problems instead of treating them

Based on known operational problems and observations, REFLECT will determine the effect of relevant fluid properties and reactions in order to enhance predictive geochemical modelling and thus the energy exploitation and life-time of geothermal power plants. By moving from reacting to occurring problems, to reflecting in advance (and acting proactively), the project outcomes can fundamentally change the problem-solving strategies of geothermal operators.

Extend databases (solubility, activity, reaction kinetics) to higher temperatures and higher salinities through lab experiments and modelling approaches

Interest for operators: Massive silica scaling frequently occurs with processing of type A fluids, whereas for saline fluids (type C) metal-rich scales, often concentrating naturally radioactive elements, form. Both types of scaling are difficult to predict and to remove.

Predictive modelling on scaling requires new equilibrium (i.e. thermodynamic-), and kinetic, data.

Determine the extent and location of the degasification front of geothermal fluids during production (field, lab, and modelling approach)

Interest for operators:

  • Formation of free gas in the reservoir can reduce the rock permeability
  • Enhanced corrosion by dissolved gases (H2S or CO2) or carbonate scaling (CO2 degassing)

To optimise the conditions of exploitation (preventing degassing) precisely determined gas dissolution constants are required.

Determine types of organic matter and microorganisms in various geothermal fluids and their effect on scaling and biofilm formation via laboratory studies

Interest for operators (type B, C fluids): Organic components can be part of scales, dissolved metal complexes, or additives (drilling mud, inhibitors). They are the energy source for microorganisms, which can form biofilms, enhance precipitation, or decompose inhibitors.

Mitigation of microbial activity and prevention of the formation of organic scales requires knowledge about the roles that organic compounds and microorganisms play in geothermal brines.

Determine heat capacity, density, electrical and thermal conductivity, sonic velocity, and viscosity at various p, T, X through lab experiments and modelling approaches

Interest for operators: Data are needed to improve exploration, reservoir engineering, dimensioning of surface installations, well and pump layout.

Optimised power plant layout requires a fluid physical dataset for a range of conditions.

Develop a downhole sampling technique suitable to collect fluid at chosen depth in hot and superhot systems (proof of principle prototype)

Interest for operators (type A fluids): Lack of knowledge about fluid-properties of distinct aquifers feeding a singular well in hot and super-hot geothermal fields leads to long term and high-cost geothermal utilization problems with surface and downhole installations (liner corrosion), and increased greenhouse gas emissions.

Optimised casing design, requires knowledge on fluid composition at depth and therefore an extension of the p-, T- range at which existing samplers are enabled to collect fluid samples.

Verification and implementation of the improved dataset by application in reactive transport modelling

Interest for operators: Current predictive model databases for simulating processes in a geothermal fluid loop are very often poorly optimised and inaccurate for high temperatures and salinities.

Extended databases need to be implemented in hydraulic-, thermal-, and chemical models.

Optimised casing design, requires knowledge on fluid composition at depth and therefore an extension of the p-, T- range at which existing samplers are enabled to collect fluid samples.

Set up a geothermal Fluid Atlas that collates information on geothermal fluid properties across Europe together with their geological setting

Interest for operators: The atlas provides easy access to information on the occurrence of geothermal fluids in different environments and potential geochemical risks prior to drilling. It also facilitates risk assessment and planning borehole and plant layout to suit fluid properties.

Requires a comprehensive gathering of existing and new data on fluid properties and their geological and geographical occurrence.

By fulfilling these goals, REFLECT aims at solving many severe problems of geothermal operation. This matches the goals of the EU Strategic Energy Technology (EU-SET) plan by ultimately reducing the cost of key renewable technologies and increasing the resilience and security of the energy system.


Investigated Fields

Expected impact

Addressing the key problem of almost all geothermal operations, REFLECT will have a major impact on the operational efficiency, project economics and viability as well as on the environmental footprint. By redefining geothermal fluid properties and their geochemical reaction constants over a large range of salinities and temperatures, a huge knowledge gap can be closed, leading to more reliable predictions of geothermal performance. The improved databases and modelling tools can be used by geoscientists and engineers to help operators optimise power plant layout and reduce maintenance costs, caused by clogging or insufficient production/injection rates.

From react to REFLECT

Our project aims at preventing problems instead of treating them

Significantly increased technology performance and reduced maintenance costs:

By addressing the main problems of geothermal operations (scaling, degassing, and corrosion), REFLECT results will offer solutions to avoid them by improving predictions of chemical reactions based on improved databases. This decreases operation and maintenance costs, minimizes downtimes, and increases the overall reliability and efficiency of the operations.

Reducing life-cycle environmental impact:

Environmental effects of geothermal electricity production are mainly associated with emissions at the site. One of the proposed outcomes of REFLECT is the significant decrease of these emissions, reducing the release of non-condensable gases to the atmosphere by determining gas dissolution kinetics, and by minimising the addition of chemicals (inhibitors) to the geothermal fluid for the prevention of scaling and corrosion.

Facilitating the exploitation of high-temperature geothermal resources:

By adapting downhole sampling technologies to higher temperatures, the correct characterisation of very hot geothermal fluids can be achieved. The expanded database of fluid properties, sampled at depths so far not directly accessible, will also enable better predictions for future developments at extreme conditions

Improving EU energy security:

REFLECT aims to increase the number of economically viable geothermal sites. By encouraging an increase of the share of geothermal energy (through the provision of a Geothermal Fluid Atlas) within the European energy market, REFLECT can help to reduce the consumption of fossil fuels.

Compensating for the fluctuating provision of electricity to the grid

from renewable energy sources by making geothermal energy provision more reliable, sustainable, and stable. By increasing the number of economically viable geothermal sites, REFLECT will help to stabilize electricity provision.

Increased electricity output and faster amortization of the power plant

due to reduced downtime and maintenance during operation, e.g. by avoiding/reducing scale formation.

Increasing the attractiveness of renewable energy technologies

by improving cost-competitiveness, reducing complexity and increasing reliability. Thereby, REFLECT is perfectly in line with the goals of the EU SET-Plan and contributes to the global energy supply by promoting renewable energies thus reducing greenhouse gas emissions.

Opening of new economic opportunities

for specialised service suppliers, applying the REFLECT approach (data, models, and Fluid Atlas). REFLECT can help to strengthen the European industrial technology base, creating growth and jobs in Europe.

Reducing the environmental impact of geothermal energy production:

By improving knowledge of the formation of free gas from geothermal fluids during production, operational procedures can be adapted, and degassing of greenhouse gases such as methane and CO2 can be reduced.

Transfer of project results to the operators

is guaranteed through the participation of power plant operators as project partners (Landsvirkjun, Pfalzwerke Geofuture) and stakeholders in the advisory board (BESTEC, EBN, Floricultura, Geothermie Bouillante, Tuzla GPP, Erdwärme Neustadt-Glewe, AAE Geothermae).


  • GFZ Germany. Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences
  • UKRI United Kingdom. United Kingdom Research and Innovation
  • BRGM France. Bureau de recherches géologiques et minières
  • EFG Belgium. European Federation of Geologists
  • IFE Norway. Institutt for energiteknikk
  • PGF Germany. Pfalzwerke Geofuture GmbH
  • UNINE Switzerland. Université de Neuchatel (UNINE)
  • ISOR Iceland. Islenskar Orkurannsoknir
  • UNIM Hungary. University of Miskolc
  • IZTech Turkey. Izmir Institute of Technology
  • TUD Netherlands. Technische Universiteit Delft
  • LVK Iceland. Landsvirkjun Sameignarfelag (LVK)
  • HI Germany. Hydroisotop GmbH Laboratorium zur Bestimmung von Isotopen in Umwelt und Hydrologie
  • TNO Netherlands. Nederlandse organisatie voor toegepast natuurwetenschappelijk onderzoek

EFG Linked Third Parties in REFLECT project

  • Belgo-Luxembourg Union of Geologists (Belgium-Luxembourg)
  • Bulgarian Geological Society (Bulgaria)
  • Croatian Geological Society (Croatia)
  • Czech Union of Geological Associations (Czech Republic)
  • Professional Association of German Geoscientists (Germany)
  • Association of Greek Geologists (Greece)
  • Hungarian Geological Society (Hungary)
  • Italian National Council of Geologists (Italy)
  • Polish Association of Minerals Asset Valuators (Poland)
  • Association of Portuguese Geologists (Portugal)
  • Serbian Geological Society (Serbia)
  • Slovenian Geological Society (Slovenia)
  • Official Spanish Association of Professional Geologists (Spain)
  • Turkish Association of Economic Geologists (Turkey)
  • National Association of Professionals in Geology and Mining (Romania)
  • Ukrainian Association of Geologists (Ukraine)

REFLECT Brochure

REFLECT Press release

REFLECT Presentation