Framework for Leased Residential Rooftops for Solar Photovoltaic in Zambia

The Zambia power grid has been inconsistent in providing reliable supply to the various sectors of the economy, especially the residential consumers with majority resorting to high charcoal usage, the least costly option. The most promising environmentally friendly option, though at a high capital cost, is the installation of solar home systems. This paper investigates the technical and financial frameworks that may guide the leasing agreement for residential rooftops to guide potential investors. A survey was conducted to investigate the awareness and economic status of residential consumers. An exponential smoothing method was used for forecasting the time-series solar power outputs and load profiles. It was determined that the minimum number of 280 W panels required to be installed in medium and high income residential areas is ten (10) (2.8 kW). The installation cost of the entire system was determined to be ZMK 66000 ($4000). It was discovered that a discounted rate of higher than 6.2% yielded a negative present value. However, the present value is positive for 3% and 5% discount rates, i.e. ZMK 8229 (USD 489.85) and ZMK 25711 (USD 1530), respectively. A payback period of 15 to 20 years is expected with the client buying power at the current utility tariffs. If an agreement is made to reduce the payback period so that at the end of that period the installation ownership becomes that of the client then the cost of electricity should be adjusted to say, worlds average price of 2.23 ZMK/kWh (USD 0.133/kWh. Since the installation lifecycle is 25 years, the saving on electricity by the client is about ZMK 200000 ($12000).