Renewable and efficient energy supply in buildings: the case of the Ministry of Communication, Science and Technology in Dar es salaam, Tanzania

Over the past few years, Tanzania has experienced frequent power blackout, which have led to power rationing. The situation led government ministries/institutions to use fossil fuel driven electric generators, which cause environmental pollution despite arithmetic increase of fuel prices, as an alternative source of power. The study area was the Ministry of Communication, Science and Technology (MCST) office building, located in the centre of Dar es Salaam city. Energy demand data of MCST building was obtained by using energy cost meter while monthly energy bills were used to obtain the energy expenses and energy use pattern respectively. Wind speed and solar radiation data were obtained from the Tanzania Meteorological Agency (TMA) and used as input to Hybrid Optimization Model for Electric Renewables (HOMER) computer software for simulation and optimization of various electric supply options. The potential and appropriate Renewable Energy (RE) resource was found to be solar energy whereby the system has total emissions of 120 t/yr CO2, 0.5 t/yr SO2, and 0.3 t/yr NOx. However, the energy installed capacity and consumption of the building were found to be 886.088 kWh and 688 kWh respectively. RE can be used as an alternative source of power and mitigate carbon emissions. Different options came out as per the study but the proposed one which is grid and solar PV hybrid system having a renewable fraction of 54%. The study recommends that, Energy Efficiency (EE) should be considered in future building designs.