Market feasibility evaluation of Solar photovoltaic integrated gasification of cattle dung: experimental study

Abstract

The widespread adoption of thermochemical gasification for converting low-heating-value biowaste into renewable energy is constrained by logistical challenges, heterogeneous feedstock properties, supply chain inefficiencies, and, most critically, an unfavorable energy input-output ratio. This study estimates the market feasibility of solar photovoltaic (PV)-integrated gasification of dried cattle dung through experimental analysis and a techno-economic-environmental assessment (TEEA), focusing on confined animal feeding operations (CAFOs). CAFO-based feedstock eliminates logistical challenges by providing readily available, locally sourced dung. Solar PV integration resolves the unfavorable energy input-output ratio by utilizing abundant solar energy, reducing reliance on grid power, and enhancing overall energy recovery. Considering Pakistan's severe energy crisis and abundant cattle resources (84 million head), we characterized dung samples from diverse breeds and diets, from different CAFOs and found consistent properties (volatile matter: 62.56-63.93%, fixed carbon: 13.18-15.13%, HHV: 15.66-16.23 MJ/kg). Solar PV-driven gasification across four isothermal scenarios (500-800°C, corresponding to 500-1100 W) demonstrated optimal performance at 800°C (1100 W), yielding maximum syngas (2.20 m³/kg) with 40.17% net energy recovery - significantly higher than grid-powered operation (23.03%). The process reduced CO₂ emissions by 1.2-1.3 kg/kg dung compared to open burning, with a projected payback period of 3.75 years for a 5 kg/day system processing 7.5 tons fresh dung annually. These findings establish solar-powered cattle dung gasification in CAFO as technically viable, economically feasible (98,703 PKR/year revenue), and environmentally sustainable, offering a practical waste-to-energy solution for developing countries.