Abstract

Climate change has the potential to affect hydropower generation by either increasing or reducing flows (discharge) and the head. This paper assessed the impacts of climate change on hydropower generation with a focus on Lujeri micro-hydropower scheme in Mulanje district, Malawi. The study analyzed trends in weather time series (air temperature and rainfall) data from 1980 to 2011 in connection to changes in river discharge and their associated impacts on hydropower generation profile. The Mann-Kendall (MK) test was used to detect trends in air temperature, precipitation and discharge. Correlation analysis was also used to uncover the relationship between discharge and precipitation as well as between discharge and temperature. The MK results highlighted significant rising rates of air temperature, precipitation and discharge in some months and decreasing trend in some other months, suggesting significant changes have occurred in the area. The relationship between precipitation and discharge was not significant (p = 0.552), while that between temperature and discharge was significant (p = 0.0001). Therefore, as temperature showed significant increasing trend, it will be associated with decrease in discharge, consequently a decrease in hydropower generation (power is directly proportion to discharge). Hence, proper adaptation measures such as standby alternative sources of energy and storage mechanisms devices should be exploited to ensure electric power is available throughout the year, especially in the hot and dry season when the discharge is usually very low.

Key words: Climate change, discharge rate, hydropower, Malawi, precipitation, temperature.