Critically evaluating the purported global “boom” in small hydropower development through spatial and temporal analysis

Due to a rapid proliferation of small hydropower (SHP) in many parts of the world, a purported boom in SHP development globally has captured significant attention in recent research. While SHP is expanding rapidly in distinct places, the global landscape is more varied. Some regions are experiencing a plateau or even declines through decommissioning efforts. To date, research has predominantly drawn on national level data to interrogate empirical outcomes of the pronounced global boom in SHP development. National level data, however, can obscure spatiotemporal variations, which are critical for understanding empirical complexities. We argue, the notion of a boom, particularly when applied without spatial or temporal context, can be problematic for adequately understanding a range of dynamics inherent within SHP planning, development, distribution, and empirical outcomes. Given regional differences, there is a need to critically investigate spatiotemporal dimensions of SHP development. Accordingly, we offer a multi-regional comparative case study analysis of SHP in four distinct regions: West and Northeast United States, Southwestern China, Central and Southern Chile, and Central Nepal. Our research interrogates patterns of spatial distribution by focusing on concentrated hotspots and considers temporal dynamics through the lens of timepeaks. This approach allows for an effective capture of empirical complexities bound in ongoing SHP development (and decommissioning). We discover rates of growth and/or decline in SHP development vary substantially depending on both spatiotemporal criteria. Resulting spatial and temporal patterns and processes can be holistically analyzed to better understand empirical outcomes for policy makers, development practitioners, and environmental planners.