World Hydropower Capacity Evaluation

Abstract

A continuous population growth and increasing energy demand combined with depleting traditional energy reserves puts a pressure on conventional methods of electricity generation. The desire and ambition to create a more sustainable society paves the way for the ‘renewables’. Hydropower or Hydroelectricity already plays a significant role in global energy production, especially the large hydropower plants with giant reservoir lakes. The contribution of small and micro hydropower however is not really clear. Smaller hydropower plants have some advantages compared to larger plants in terms of sustainability, local benefits and electricity supply in remote areas. The exact location of potential hydropower plants is mostly unknown and the total potential of all combined hydropower capacities for a certain region has not been evaluated as well. This research aims to give insight in the potential of hydropower for a specific region and distinguishes micro, small and large hydropower. In order to evaluate the global hydropower potential a systematical method has been developed to simulate input data and check whether there is hydropower at a specific location. The approach is based on a distributed model and raster data. The world is divided into cells with a 3” (three seconds or 92m near the equator) resolution. For each and every cell the hydropower capacity is systematically determined. In order to do this the two basic components for hydropower, head and discharge need to be evaluated for each cell. The discharge is calculated with help of the HydroSHEDS’ DEM and DIR datasets combined with the GRDC Runoff fields’ dataset. Based on the Flow Direction, derived by HydroSHEDS a ‘runoff weighted’ flow accumulation was executed to obtain the accumulated runoff for each cell which is converted into discharge. The head is calculated with the cell size and slope within each cell. The slope was derived from a global 3” DEM which has been modified with the discharge map to obtain a RiverDEM which forms the basis for the slope calculation. Hydropower is calculated within each cell using the Input Variables ‘turbine efficiency’, ‘minimum discharge’ and ‘minimum head’. The results are filtered into micro, small and large hydropower locations. To give insight in the total hydropower capacity for a specific region the total hydropower is accumulated per category for a region of 0,50 degree times 0,50 degree (about 50 km2). The final output is a global map of accumulated hydropower per category with a resolution of 0,50 degree. It is computed that the total gross theoretical hydropower capacity potential is about 20TW with Asia as the largest contributor. Large hydropower accounts for over 80% of this potential while micro hydropower only accounts for 2% of the total potential capacity. This paper demonstrates new, insightful images on spatial hydropower distribution, showing that Colombia, Myanmar, Indonesia and Madagascar are examples of areas with extensive hydropower potential. Overall this study provides a consistent global modeling approach that allows both a quick comparison of hydropower potential between regions as detailed information on a specific hydropower location.