Large-scale resource assessments for solar photovoltaics: A review of potential definitions, methodologies and future research needs

Identifying suitable locations for solar photovoltaic (PV) systems is key to a successful global energy transition. However, PV assessments vary widely in terms of input data used, methodological approaches applied, and therefore ultimately in the resulting total potentials, making their comparison and interpretation challenging. Here, we review the current literature with respect to existing definitions of potentials, associated criteria as well as methodologies to identify current trends in this field and potential future research directions with a focus on large-scale assessments covering at least an entire country or a large region within a very large country. We observed a wide range of assumptions and methodologies used in such studies, sometimes combined with lack of transparency in documentation. Furthermore, the literature lacks consideration of system integration costs to account for the variable PV generation profile. The inclusion of non-technical factors is challenged by the lack of consistent theoretical and methodological approaches and interdisciplinary collaborations, as well as limited availability of data. Combined with a frequent lack of validation attempts, these aspects ultimately limit the comparability and reliability of results. The comprehensive overview in this review assists modelers and decision makers in utilizing best-practice methods for PV potential assessments to improve traceability and comparability of future assessments.