Mapping global water-surface photovoltaics with satellite images

Abstract

The recent boom in solar photovoltaics has intensified global competition for land use. Water-surface photovoltaics (WSPV) has also increased globally as an efficient alternative to land-based photovoltaics. Determining the spatio-temporally distribution of WSPVs is essential for estimating renewable energy capacity, evaluating the associated socio-environmental impacts, and managing and planning WSPV projects. However, a comprehensive inventory of WSPV locations and extent on the global scale is still lacking. To address these issues, we developed a workflow for identifying WSPVs using time-series optical satellite images and generated the first global-scale WSPV inventory map. The results demonstrate that WSPV has experienced rapid expansion with an average annual growth rate of 20.6% between 2019 and 2021. By 2021, a total of 1027 WSPV projects in 27 countries were detected, covering a water area of 272.0 km2. Asia dominates the fast-emerging WSPV development, with eleven countries that rank in the top fourteen for WSPV are located in Asia. The development of WSPV in China far exceeds that of all other countries, accounting for 95.1% of the total global WSPV area. The global installed capacity of WSPVs is estimated at 12.9 GWp, >20% of which are floating WSPVs (2.6 GWp). The results advanced the understanding of the global spatial-temporal dynamics of the recent WSPV development and will be useful for informing future global and regional renewable planning and management for policymakers and project stakeholders. It also provides a basis for further studies on assessing the potential impact of WSPVs.