Agro-Industrial Kiwifruit and Apple Waste as a Renewable Feedstock for Biomethane Production—A Study of Feedstock Viability

New Zealand’s kiwifruit are major contributors to the nation’s horticultural exports. However, it produces large volumes of organic waste. This study investigates the potential of agro-industrial kiwifruit waste as feedstock for hydrogen generation via anaerobic digestion and steam reforming. Two feedstock mixtures were examined, a 50:50 blend of kiwifruit and apple, and a second mixture supplemented with potato to mitigate acidification. Cow manure was used as a cost-effective inoculum for anaerobic digestion. Physicochemical analysis confirmed that both feedstock mixtures were generally suitable. Biomethane potential tests were conducted. Methane yields ranged from 0 to 20 mLCH4/gVSadded, with the best result 45 mLCH4/gVSadded achieved by mixture 2 at ISR 4, corresponding to a 46.5 % carbon conversion. From a total waste amount of 476 tonnes, a theoretical yield of 8,000 m3 of biomethane could be produced. Steam methane reforming simulations confirmed the viability of biogas as an alternative to natural gas, although its higher sulfur content may necessitate more frequent catalyst replacement. With a 46 % methane conver-sion efficiency, an estimated 7,600 m3 of hydrogen could be produced. This study offers a practical foundation for converting kiwifruit and apple waste into renewable hydrogen, supporting New Zealand’s decarbonization and circular economy objectives.