Five decades (1965-2014) of CLM5, ERA5 and GLDAS Groundwater Recharge in Africa with Implications for Green Hydrogen Production

Abstract

This study investigates the spatiotemporal distribution of decadal mean groundwater recharge (GWR) across Africa from 1965 to 2014. The analysis employs the Community Land Model version 5 (CLM5) as the reference dataset, alongside the European Reanalysis dataset version 5 (ERA5-Land) and Global Land Data Assimilation System version 2 (GLDAS_2.0) as additional dataset. Groundwater recharge calculations utilize a water balance approach, revealing mean decadal recharge rates of 45.5 mm/year for CLM5, 129.9 mm/year for ERA5-Land, and 155.4 mm/year for GLDAS. Remarkably, regions such as Central Africa, Central-East Africa, West Africa, South-East Africa, and North-East Africa (including Ethiopia) demonstrate substantial groundwater availability. Fascinatingly, a strong similarity emerges between Precipitation and Evapotranspiration across the models. Specifically, the average annual precipitation stands at 644.6 mm for CLM5, 627.2 mm for GLDAS, and 691.6 mm for ERA5-Land. Correspondingly, the annual evapotranspiration rates are 480.8 mm for CLM5, 462.8 mm for GLDAS_2.0, and 526.7 mm for ERA5. Statistical analyses establish a noteworthy correlation between CLM5 and GLDAS_2.0. This correlation underscores the reliability of the models in assessing groundwater recharge. The identification of regions with elevated groundwater recharge potential lays a crucial foundation for informed decision-making in the establishment of green hydrogen projects. Moreover, it emphasizes the indispensable role of accurate hydrological modelling in shaping sustainable water resource strategies for advancing energy sustainability. In moving forward, collaboration between stakeholders, policymakers, and researchers is pivotal. Such partnerships can facilitate the assessment of the feasibility of green hydrogen projects in areas with significant recharge potential. This assessment must holistically consider both groundwater availability and the broader landscape of renewable energy resources. This study's findings hold substantial implications for steering environmentally conscious energy initiatives and ensuring harmonious resource management.