6. Energy Production from Agro-Wastes: Comparative Studies for Wine Vinasse and Pig Slurry

Portuguese agriculture holds significant importance in the country's culture and economy. While it has embraced advanced production methods, waste management remains a challenge. However, agro-wastes offer a promising solution through anaerobic digestion, contributing to waste reduction and promoting sustainable practices. This study focuses on the energy potential of two specific agro-wastes: wine vinasse (WV) and pig slurry (PS). The results indicate that both residues can be effectively utilized for biogas production. WV demonstrated a specific methane production (SMP) of 1.03 NL-CH₄/g-VS, while PS showed an SMP of 0.57 NL-CH₄/g-VS. When converted into electrical energy, these findings translate into energy production potentials of 3.00 kWh/kg-VS and 1.52 kWh/kg-VS for WV and PS. Alternatively, direct burning of the biogas for heating purposes can generate 7.04 and 3.56 kWh/kg-VS for WV and PS, respectively. Although the energy generated may not fulfill the entire industry's demand, it significantly reduces dependence on fossil fuels. This green and sustainable alternative offers cost savings and effective management of agro-waste. By harnessing the energy potential of WV and PS, industries can make strides toward a more environmentally friendly and economically viable future.