TECHNO – ECONOMIC AND ENVIRONMENTAL ASSESSMENT OF WASTE-TO-ENERGY DEVELOPMENT IN NIGERIA, 1981 - 2017

Abstract

Poor waste management in Nigeria results in environmental and socioeconomic problems. Managing wastes through the agelong approach of burning leads to climate change while landfill leachate reduces soil and ground water quality. Limited number of studies exist on the potential impact of managing wastes using waste-to-energy recovery generation (ReGen) technology in Nigeria and how waste-to-energy (WtE), environmental quality (EQ), and sustainable development (SD) are connected. Therefore, this study investigated the technoeconomic and environmental impact of using ReGen for waste management in Nigeria. Environmental Kuznets Curve (EKC) hypothesis provided theoretical framework. Data on indicators of WtE in Nigeria were sourced from the World Development Indicators (1981-2017). These indicators include WtE, environmental footprint, green national net income, human development index, fossil energy consumption, per capita income, energy consumption, capital investment, urbanisation, trade intensity and land quality index. Augmented Dickey Fuller was used to ascertain the stationary of the variables specified in the model. The bound test was preferred based on the stationary of variables at level and at difference. Since the variables are cointegrated at difference order, the secondary time series methodology described as Autoregressive Distributive Lag (ARDL) was used to estimate the short and long run relationship of the model. Thus, the relationship among WtE, EQ and SD was analysed using ARDL technique at α=0.05. The bound test was used to test for cointegration among the study variables. Technoeconomic viability of ReGen was evaluated with Cost Benefit Analysis. Values of the bound tests (F-Statistics) stood at 19.23 and 5.64 which are above the upper critical values of 4.76 and 3.83 respectively at 5% p-value. This showed that there is cointegration indicating the presence of both short and long run relationship. The coefficient of 5.02 implies a positive relationship between WtE and EQ, that is, a 1% increase in WtE, leads to 5.02kt increase in EQ. The coefficient of 1.25 indicates inverse relationship between WtE and SD, which means, a 1% increase in WtE, reduces SD by 1.25kt. The WtE significantly drove EQ and SD. Though in 2017, WtE affected EQ and SD negatively, however it translates to positive development in the long run. EQ and energy consumption exhibit positive relationship in the short to long run. The existence of EKC hypothesis in Nigeria was established, which contributed to environmental degradation at the early stage and declined with increasing economic growth in the latter stage. The generating cost of ReGen electricity was $0.71/kWh with 6-8 years payback period and better environmental socioeconomic benefits than equivalent diesel generators. The ReGen reduced waste by 90.0% with 332 kW net energy output from 980 kg waste/hour. The technoeconomic and environmental assessment of waste-to-energy enhanced environmental quality and sustainable development between 1981 and 2017 in Nigeria. The use of waste-to-energy recovery as a technology for solving waste management problems is adequate, economical and environmentally viable. Government should provide enabling environment for increased investment in wasteto-energy recovery generation.