Assessment of geothermal resources for power generation on La Palma Island, Canary Islands

Canary Islands archipelago is the sole region in Spain with a recognized potential of geothermal resources suitable for power generation. Supported by geological and geothermal evidences, the interest of integrating the geothermal power in some islands has risen due to the excellent prospect that this resource offers to isolated and high fossil fuel dependent power systems (renewable nature, lower cost, dispatchability). In this paper, the results of the first probabilistic assessment of the geothermal power potential of La Palma island are presented. Starting from the information obtained in previous geophysical and geochemical studies two specific zones, named as L1 and L2, are selected for further analysis. The stochastic Monte Carlo simulation approach is applied in combination with the well-known geothermal resource assessment volumetric method. Intervals for the most relevant reservoir characteristics are derived from gravimetric, magnetoteluric and ambient seismic noise tomography techniques, whereas other parameter values are estimated based on the current general literature or adopted from reference projects.

The obtained results show power capacity potentials of 10.9 MWe and 6.7 MWe for L1 and L2 zones respectively at a 90% confidence level. With this capacity in place, the contribution of renewable electricity would rise up to 45.2% or 31.0% if only the L1 or L2 potential would be exploited respectively. In addition, other benefit indicators such as land use, CO² emission abatement or the generation cost have been quantified. Finally, to enhance the relevance of the results, a sensitivity analysis of the Monte Carlo outputs was performed as a function of the most likely reservoir volume and recovery factor values. In this case, power potential ranges of 8.3 - 13.4 MWe and 5.2 - 8.3 MWe for zones L1 and L2 respectively are found.