Domestic hot water technology transition for solar thermal systems: An assessment for the urban areas of Maputo city, Mozambique

Abstract

Solar thermal systems have been widely used to increase energy efficiency in residential sector, since it became one of the top priorities in many countries to mitigate the electricity shortage. Thus, for better deployment of solar thermal systems in the residential sector it is important to understand the household electricity consumption and energy usage for domestic hot water, though developing countries lack this type of accurate data.This work assesses a domestic hot water technology transition to solar thermal systems in the urban areas of developing countries, taking as case study Maputo city, in Mozambique.First, a survey was made to the domestic hot water needs, demand and usage, in 700 households, 28 neighbourhoods of Maputo, having identified the sources and technologies used to heat water and quantified the domestic hot water needs. Then, the impact on energy demand, cost and CO2 emissions of domestic hot water technology change to solar thermal systems was modelled as well as the impact on electricity grid.The survey results point that the predominant energy sources used for domestic hot water in urban areas are electricity and biomass with nearly 46% and 41% shares, respectively. Further, results show that the domestic hot water technology used depends on household income, being the electric water heaters mostly used in households with relatively high-income.The technology transition to solar thermal systems results in a positive impact on the grid by reducing up to 65.7% the domestic hot water electricity demand and 78.7% of the CO2 emissions, while the economic savings are up to 244 USD/household/year. However, peak load is expected to increase by 11%, suggesting the need for load management policy implementation.