Authors and contributors
Pharoah Le Feuvre
IEA (2019), "Tracking Power", IEA, Paris https://www.iea.org/reports/tracking-power-2019
Electricity generation from geothermal increased by an estimated 5% year-on-year in 2018, more than the average growth of the previous five years. However, the technology is still not on track to reach Sustainable Development Scenario (SDS) levels, which would require that generation increase 10% per year to 2030.
Over the last five years, geothermal capacity additions averaged 500 MW per year. Most of this growth was in emerging economies because they have abundant and untapped resource availability.
In the next five years, average annual geothermal installations are expected to accelerate to almost 700 MW, driven by strong project development, mainly in Indonesia, the Philippines, Kenya and Turkey, with smaller-scale deployment in 25 other countries.
Despite the recent acceleration in deployment, pre-development risks are still a major barrier to securing financing for geothermal projects, which hampers faster expansion.
Geothermal energy technologies have differing levels of maturity. The exploitation of hot rock resources, e.g. by means of EGS which is currently in the validation phase, has particular potential for improvement
Long-term, sustained and substantially higher research, development and demonstration resources are needed to accelerate cost reductions and design, and bring novel geothermal concepts to market. These advanced technologies have to be proven in pilot plants, meaning that strong government support for innovative small plants is needed.
R&D will need to focus on understanding better how fractures open and propagate in different stress regimes and rock types, in order to be able to better assess the hot rock potential. Similarly, a common approach in identification of advanced hydrothermal resources will help assessing its potential.
Drilling costs account for 40‑70% of the total capital costs of a geothermal power project. It is also a very time-consuming part of the project.
So far, utilisation of geothermal energy has been concentrated in areas with naturally occurring water or steam, and relatively permeable rock. However, the vast majority of geothermal energy within drilling reach – up to 5 km with current technologies and economics – is in relatively dry, low-permeability rock. Heat stored in low-porosity and/or low-permeability rock is commonly referred to as a hot rock resource, and in contrast with most hydrothermal resources in use today for power generation, hot rock resources are available worldwide.
Geological databases already exist for several parts of the world, but they could benefit from incorporating and aggregating the more complex data emerging from advanced remote sensing and monitoring of hydrothermal resources around the world. Combining these at the greatest granularity, extending them geographically, and reinterpreting, recompiling and standardising them would enable the creation of a publicly accessible, globally relevant database for use in assessing, accessing and exploiting geothermal resources.