RENEWABLES - HYDRO

This section presents a summary of the hydrological studies and the hydropower potential studies performed. 159 sites for development of large scale hydropower plants have been identified and studied, of which 20 were selected and considered as structural sites for the future power grid of Angola. Further, 100 sites were studied for development of small hydro power plants, totaling 607 MW, either for grid connection or for the development of
isolated mini-grids for rural electrification.

The hydro resource assessment required an exhaustive hydrological study based on the available meteorological and hydrometrical time series, having been evaluated data from 302 rain gauges and 289 stream gauge stations and been modeled the national and international drainage basins that contribute
to the runoff of the Angolan territory.

Angola has a mean annual rainfall of 1060 mm, concentrated in the months of November to March. Rainfall is not evenly distributed across the country, being the Northeast the wettest region with a mean annual rainfall of around 1400 mm, and coastal areas and the South the driest, with a mean annual
rainfall under 500 mm.

In Angola the wettest season coincides simultaneously with the warmest, which yields a decrease on the effective rainfall through evaporation and evapotranspiration. Nonetheless, runoff is usually high, in Northeast and Central Plateau.

RAINFALL AND TEMPERATURE MAP

The Angolan hydro-network is extensive, with 47 main drainage basins, and offers huge hydropower potential. Within the scope of the study, drainage basins were modeled for the purpose of elaborating the first ever surface runoff map of the country using a water-balance based methodology comprising the geographical distribution of rainfall and temperature.
Subsequently, available river flow and head were jointly assessed throughout the territory for the development of the Hydropower Potential Atlas.
It is envisaged that the hydropower potential of Angola is around 18 GW, largely concentrated on the Cuanza, Longa, Queve, Catumbela and Cunene basins. The Atlas evaluated only already known locations with focus on small hydro.

SURFACE RUNOFF MAP AND HYDROPOWER POTENTIAL ATLAS

The assessment of hydropower projects in Angola was based on a thorough survey in Angolan and Portuguese archives for previously identified locations with hydropower potential, yielding on the collection of 159 identified locations for large hydropower projects and the evaluation of a list of around one
hundred selected locations for small hydropower projects.

The 159 large hydropower locations were analyzed and ranked using a comprehensive environmental strategic assessment after which the top twenty most relevant projects for the future transmission grid were selected and studied in higher detail.

The near 100 locations selected for small hydropower projects were also technically and economically evaluated. Their adequacy for grid connection was assessed and about thirty isolated mini-grids were studied.

SMALL HYDROPOWER POTENTIAL

Small hydropower plants are the most economical alternative for the production of electric energy amongst the studied renewable energies technologies. However, projects tend to have a wide range of costs with levelized costs of energy varying from 20 USD/MWh and more than 1.000 USD/MWh.

From the near 100 locations selected for small hydropower (totaling around 600 MW of capacity), about 35 locations (approximately 400 MW), are feasible for the development of projects with very competitive levelized costs of energy and greater ease of financing and energy dispatch either from
electric grid connection or to electrify rural areas. In case of the later, many could require backup support of thermal units for energy production in the dry season.

LEVELIZED COST OF ENERGY OF THE STUDIED SMALL HYDROPOWER PLANTS

Example of plan details of the hydraulic structures and devices of the hydropower scheme of Zenzo I.

HYDROPOWER POTENTIAL ATLAS