Sustainable water pumping in refugee camps: solar PV / diesel hybrid scenarios at Nyarugusu, Tanzania

Globally, refugee numbers have reached unprecedented levels, with the average length of protracted refugee situations now 26 years. UNHCR is seeking solutions for refugee water supply with low longterm operational costs and reduced environmental impact. Solar PV energy provides the ideal solution to efficiently power water pumps in remote locations with high solar irradiation. This paper describes valuable learning from a solar PV diesel hybrid water pumping system installed at Nyarugusu refugee camp in Tanzania, and analyses economic and environmental benefits. A sustainability assessment framework is developed to optimise performance, derive local future fuel price projections, and apply life-cycle environmental impact to simulated generation scenarios. Results show fuel combustion as the dominant recurring component of cost and impact, while the embedded impact of module and inverter manufacture was also significant. Hybrid scenarios provided economic, energy and CO2e emissions payback in 5 years; and a hybrid with a 20% oversized PV array provided 45% lower discounted levelised cost of electricity (LCOE) and impact than a diesel generator. The success of this sustainability assessment framework supported further analysis to determine the marginal cost of oversized PV arrays, and to quantify the value of surplus energy.