The United Nations Development Program reported that two-thirds of the world's population will be living in cities by 2050, which would account for more than 60% of the world's energy consumption. Developing countries experience substantial urbanization and informal settlements compared with other parts of the world. This indicates a paradigm shift in the global energy landscape, which heralds an increase in greenhouse gas emissions. According to Indonesia's National Energy General Plan (PR 22), solar panels are expected to cover at least 25% of rooftops. In Uganda, the Sustainable Energy for All (SE4All) program aims to ensure high penetration of solar energy in the country. This study aims to integrate clean energy into low-cost housing development for sustainable cities in Uganda and Indonesia. We propose an optimal energy system and examine the most significant design parameters that exhibit a desirable performance ratio and energy yield. This project was undertaken in two stages: energy yield estimation and detailed energy system design using two different software programs. Stage 1 aimed to estimate the energy yield based on the available roof area considering existing homes in Uganda and Indonesia. A photovoltaic (PV) array was designed with suitable inverters, tilt angles, and orientations. Stage 2 was intended to determine the optimal tilt angles. Five different PV systems were developed and tested using the optimal tilt angle determined earlier. Finally, an optimizer was integrated into the PV system to investigate potential improvements in the energy yield. The inclusion of an optimizer significantly increased the energy yield from 0.5% to 5.3%. For Uganda, the levelized cost of electricity (LCOE) with and without an optimizer ranged

PurposeThis paper aims to design an optimum vertical axis wind turbine (VAWT) and assess its techno-economic performance for wind energy harvesting at high-speed railway in Malaysia.Design/methodology/approachThis project adopted AutoCAD and ANSYS modeling tools to design and optimize the blade of the turbine. The site selected has a railway of 30 km with six stops. The vertical turbines are placed 1 m apart from each other considering the optimum tip speed ratio. The power produced and net present value had been analyzed to evaluate its techno-economic viability.FindingsComputational fluid dynamics (CFD) analysis of National Advisory Committee for Aeronautics (NACA) 0020 blade has been carried out. For a turbine with wind speed of 50 m/s and swept area of 8 m2, the power generated is 245 kW. For eight trains that operate for 19 h/day with an interval of 30 min in nonpeak hours and 15 min in peak hours, total energy generated is 66 MWh/day. The average cost saved by the train stations is RM 16.7 mil/year with battery charging capacity of 12 h/day.Originality/valueWind energy harvesting is not commonly used in Malaysia due to its low wind speed ranging from 1.5 to 4.5 m/s. Conventional wind turbine requires a minimum cut-in wind speed of 11 m/s to overcome the inertia and starts generating power. Hence, this paper proposes an optimum design of VAWT to harvest an unconventional untapped wind sources from railway. The research finding complements the alternate energy harvesting technologies which can serve as reference for countries which experienced similar geographic constraints.

Nearly one-quarter of the world's urban population lives in informal settlements or encampments, most in developing countries but increasingly also in the most affluent countries. Many residents live in overcrowded, insecure dwellings, without water and sanitation, fearful of eviction and subject to preventable life-threatening illnesses. UN Sustainable Development Goal 11: ‘Make cities and human settlements inclusive, safe, resilient and sustainable’ is committed to ensure access for all to adequate, safe and affordable housing and upgrade slums by 2030. There is therefore an urgent need for more affordable and permanent housing to be developed. This paper presents a review of the construction and energy aspects of affordable housing developments for informal settlement dwellers. The conditions of existing informal settlements in Global South countries have been researched and various case studies of informal settlement upgrading programmes are presented. The potentials of solar energy technologies in development of green affordable houses in case study countries Uganda and Indonesia are assessed.