13 November 2020

Demonstration small scale Organic Rankine Cycle (ORC) machines have been installed at geothermal sites in Vermillion/ France, Soultz-sous-Forets/ France and at Grásteinn Farm in Iceland. The ORC modules use HCFO-1233zd(E) as the working fluid. One aim of the project is to demonstrate the feasibility to convert heat into electricity from various low flow and/or low temperature (70 - 120°C) geothermal sources using a small- scale ORC device.

HCFO-1233zd(E) has been chosen as the ORC working fluid for its very interesting performance for the low temperature ORC applications. The use of this working fluid, along with turbo expander technology, makes possible the “low” temperature heat recovery and conversion even with geothermal water at 80°C. HCFO-1233zd(E) has an ultra-low GWP (1, AR5 value) good safety characteristics (non-flammability and low order of toxicity) and is classified under ISO 817 as A1. It also has good stability at the ORC operating temperatures.

The ORC machines have been customized so that they can perform under the various and drastic geological conditions encountered on each site in Iceland and France. ORCs have been proposed for compatibility with the particularly corrosive conditions often found in geothermal wells. The 6 demonstration sites were selected at 3 different geological contexts, i.e. sedimentary, granitic and volcanic rock.

According to the MEET newsletter, since its commissioning on 12th of June, the first ORC module installed in Chaunoy (France) on the Vermillion site has already produced 11 MWh. It is approximately the annual energy consumption of 50 m² apartment occupied by 2 people. The Icelandic module was received at Grásteinn Farm (Iceland) in July. The third module arrived at Soultz-sous-Forêts (France) at ES-Geothermie geothermal power plant at the end of August.

Image from MEET website: Small scale ORC module installed in the Soultz-sous-Forêts geothermal power plant. The module is composed by Gasket Plate Heat Exchanger, an ORC and an internal cold loop with a dry cooler. This image is subject to MEET copyright and is reproduced here with their kind permission.

About MEET - Multi-sites EGS Demonstration: The MEET Project (Multidisciplinary and multi-context demonstration of Enhanced Geothermal Systems exploration and Exploitation Techniques and potentials) aims at boosting the development of Enhanced Geothermal Systems (EGS) across Europe in various geological contexts (sedimentary, volcanic, metamorphic and crystalline) by different means. The project started 2 years ago.