IDDP – the economics of a plant utilising ultra-high temperature geothermal resources
A study conducted by Icelandic engineering group Mannvit and Norwegian Equinor reveals the economic benefits of a GeoMagma geothermal power plant vs a conventional state-of-the-art geothermal power plant utilising high-temperature resources found based on the Iceland Deep Drilling Project.
Despite things having been a bit quiet around the Iceland Deep Drilling project, there is ongoing research. Among them is GeoMagma, a project looking into utilising a ultra high temperature geothermal system for power generation.
In a presentation at the GRC Annual Meeting in 2018, Mannvit together with Equinir (formerly Statoil) shared details on a comparison of GeoMagma with Conventional State-of-the-Art of geothermal power production, based on a study done by both.
The comparison was based on a gross output geothermal plant with two 45 MW power generation units, fueled by 3 wells per pad in the conventional set up and 1 well per drill pad for the GeoMagma plant. Wellhead pressure assumed for the conventional plant was 15 bar, while 80-120 bar in the GeoMagma scenario (Details in the presentation linked below).
Going over the costs for the construction and operational costs of the two scenarios, the main savings – clearly – are for the drilling part, as one would not need to drill as many wells. For a GeoMagma Plant the cost for wells is less than half of the cost for drilling wells in the conventional set up. This likely does not seem to be as much savings, but the drilling depth differs for both scenarios. While both have reinjection wells with a depth of 1,500 meters, the production well for the GeoMagma project are 4,500 meters deep and a conventional around 2,500 meters.
The overall cost to develop and built the plants is estimated at USD 371 million (around USD 4.12m/ MW) for a conventional geothermal plant, while USD 308 million (around USD 3.4m/ MW) for a GeoMagma plant.
Looking at the operational cost, a conventional plant costs around USD 4m/ year, while a GeoMagma plant would require about USD 3.2 million/ year.
Based on this, the authors state an 18% saving potential for GeoMagma vs Conventional State-of-the-Art geothermal power plants, based on levelized cost of electricity. The savings are mostly related to fewer production wells.
But there remain challenges, among them increased risks with the depth of the system, as well as the required adaptation/ development of equipment, systems, and methods for a system of such high temperature and high pressure.