In this study, two most common biological waste to energy conversion techniques have been analysed and compared on the basis of methane generation and energy recovery potential. The biogas generation potential has been estimated using anaerobic co-digestion experiment. The main substrate used for this study was food waste, while cow dung and anaerobic digester sludge were used as co-digestion substrates. Food waste was used because of its maximum composition (36% of total wastes) in the study area (Dhanbad city, India) with high biogas generation potential. Cow dung acted as a natural buffer, while anaerobic digester sludge was a source of active inoculum. Based on the maximum biogas yield of 402 mL g−1 VS and annual food waste generation rate in the study area, the energy recovery potential using anaerobic digestion was estimated to be 6.59 × 106 kWh year−1. Presently, the wastes in the mixed form are being dumped on a large abandoned land with an approximate area of 93 ha in the outskirts of Dhanbad city in an uncontrolled manner. The annual landfill gas generation from the existing landfill has been estimated using Landfill Gas Emissions Model (LandGEM) based on the waste characteristics, anticipated landfill life and other region-specific parameters of the present study area. The maximum electrical energy recovery potential of 44.62 × 105 kWh from landfill gas has been estimated for the year 2041. Although, the results are based on the waste generation and characteristics of Dhanbad city, the comparison methodology can be applied to other cities.