Harnessing the potential of geothermal energy: are we ready for a geothermal revolution?

TWI Ltd is currently working on a number of geothermal heat and power projects namely:

  • GeoCoat: Developing Next Generation Coatings for Geothermal Power Plant

Led by TWI, the project aims to develop novel high performance, specialised corrosion- and erosion-resistant coatings for exceptionally harsh environments. These high performance corrosion and erosion resistant coatings are based on selected high entropy alloys (HEAs) and ceramic/metal mixtures (Cermets) to be applied through high velocity oxy fuel (HVOF) thermal spray, electro spark deposition (ESD), electroless plating, and laser cladding. Although originally designed to target the key failure points within geothermal power plants, the coatings developed have cross sector benefits and can potentially be applied to other sectors, such as glass, paper, oil and gas, food and drink, etc.

  • Geo-Drill: Holistic Drilling Solutions for Cheaper Geothermal Power ()

The project aims to reduce the high costs associated with drilling by addressing the materials challenges associated with the wear and fracture of drilling components. The Geo-Drill concept is based on three technology pillars:

  1. a) Reduced drilling cost through hydraulic DownTheHolefluid/mud hammer
  2. b) Advanced drill monitoring through low-cost and robust 3D printed sensors
  3. c) Improved component life through advanced materials and coatings

The strength of these technologies will be combined to meet the unified objective of developing novel drilling technologies that will significantly reduce the cost of deep geothermal drilling, with a targeted depth of 5 km and high temperatures of 250°C and above.

  • GeoSmart: Towards Flexible and Efficient Geothermal Systems 

Geothermal energy is currently engineered as an “always on” baseload supply in power generation, due to the limited flexibility to throttle the well without scaling and liner fatigue problems, and is engineered for maximal efficiency at this output level. Project GeoSmart, aims to address the strategic flexibility required from European geothermal installations, as they become significant energy sources over the next 20-30 years, replacing decommissioned fossil fuel plants.

GeoSmart aims to optimise and demonstrate innovations to improve the flexibility and efficiency of geothermal heat and power systems, by developing a suite of equipment and tools including:

  1. Energy storage and power block management innovations to provide daily flexibility
  2. Integration of more flexible Organic Rankine Cycle (ORC) systems that can cope with variations in needs in the electricity markets
  3. Combined Heat and Power (CHP) supplier to extract more heat from the post-generator (“waste” heat) brine outflows when required for increased heating supply during colder weather
  • S4CE: A well-established interdisciplinary network of scientists to trust the environmental safety of geo-energy operations (https://science4cleanenergy.eu/)

The project promotes the benefit of a multi-sensor approach in managing sub-surface operations. TWI is leading the work carried out in WP6 within the project related to the Implementation of Novel Technologies in the field sites described before.

Based on the aforementioned geothermal projects, a workshop where the opportunities and challenges related to geothermal energy, took place at TWI on the 10th of October. Main points within the workshop were the current market trends and the state of the power sector by hosting major stakeholders such Zorlu Energy, International Geothermal Association (IGA), Enel Green Power, IGF, Vito, ON Power and UCL. Based on the discussion during the workshop, during the latest years there is a continuous effort to move from Oil and Gas to Geothermal energy. There are many advantages associated with that among which are sustainability and environmentally friendly routes to manage the needs of the humanity.

The challenges related to geothermal energy were examined based on three main points of reference:

  • Overall challenges related to geothermal energy
  • What role could technology and innovation play with respect to materials science to address those challenges?
  • How monitoring of seismicity, rock mechanics and mineral analysis techniques can help towards the right exploitation of geothermal energy?

The overall challenges related to geothermal energy as Marit Brommer Executive Director from IGA mentioned are:

  • The geothermal sector is not unitedly focused on the business case, profitability and success stories. This makes the technology not attractive for investors as they are confronted with the high upfront costs and a considerable risk profile
  • Successful exploitation requires scalability and the geothermal sector needs to move from prototype to customisation

From a materials science point of view as Francesco Fanicchia Senior Project Leader at TWI mentioned:

  • Enhancing the reliability of geothermal power plants for is of paramount importance if we want to facilitate the use of this form of renewable energy. This is specifically relevant because materials used as alloys for components in geothermal power plants currently suffer from a range of damage mechanisms, mainly related to corrosion, erosion and scaling
  • There is not one single material able to withstand all of the different damage mechanisms encountered in geothermal energy production
  • Understanding how these damage mechanisms develop is of fundamental importance if we want to develop materials able to withstand them

In terms of seismicity monitoring as Piotr Salek Geophysicist at the Department of Seismology at IGF mentioned:

  • Within the production of geothermal energy increased level of seismicity is expected, therefore several aspects need to be taken into account
    • Safety
    • Environment
    • Knowledge

Monitoring of seismicity can provide an early warning information in case of any operations problems and can also help with mitigation of hazard affecting directly the infrastructure of the site (well integrity, casing, boreholes, etc)

  • It is extremely important to gather as much information and data as possible during operations. This can be used later by scientists for deeper understanding of the physical processes, performing detailed analysis towards reduction of potential failures in future operations
  • Monitoring of seismicity provides quantitative measurements that when used appropriately, can help with mitigation of hazard associated with induced seismicity

Rock mechanics and mineral analysis techniques are also of high importance as Catalina Sanchez-Roa, Research Associate from UCL presented:

  • Rock mechanics is a field of research that allows to understand how fractures behave at the pressure conditions that occur in natural reservoirs. This field of research combines theoretical, experimental and modelling techniques to explain the role of the stress fields in fluid flow and mineralization in the Earth´s crust. Therefore, it is crucial to the overall operation
  • Mineral analysis and geochemistry are tools that allow to dig into the chemical changes that transform, dissolve or precipitate minerals at depth. The consequences of these changes can deeply affect the efficiency of the whole reservoir
  • it is important to look at the geothermal system as a whole and combine physico-chemical perspectives when exploring, assessing and developing a geothermal field

This workshop was a perfect opportunity to exchange ideas regarding geothermal energy and the ways to harness it. Apart from that, a showcase of H2020 initiatives at TWI was presented with the main collaborative projects S4CE and Geo-Coat. The workshop ended with a very fruitful panel discussion of all the participants towards the identification of solutions for obstacles to the economic exploitation of geothermal energy resources concluding on the fact that the lack of standards as well as the high costs for operation and maintenance are a major bottleneck for the appropriate harnessing of the geothermal energy resources.

Authors: Sofia Sampethai