The 2050 Clean Energy Master Plan, which entails a transition to clean energy by 2050, has been announced for Busan, South Korea. It includes target and market potential supply for solar and wind energy in 2050. As natural-gas-powered fuel cells are considered in the Master Plan, this study examined the extent to which natural gas can be replaced by hydrogen produced in Busan. EnergyPLAN was employed to simulate the balance between supply and demand considering the deployment of electric and hydrogen vehicles. Hydrogen for the fuel cells is postulated to be produced via electrolysis, employing possible surplus electricity and extracted from municipal solid waste. The results indicate that surplus electricity can be expected in both target and market potential supply scenarios under the target demand in 2050. The surplus electricity from target and market is 1.77 and 6.26 TWhe, respectively. With 0.68 TWh-H2 from waste, the total hydrogen production is 1.97 and 5.25 TWh-H2, accounting for 15.2% and 40.4% replacement, respectively. Regarding the target supply and BAU demand, the electricity balance is in deficit, necessitating electricity import from neighboring provinces. The CO2 emissions of the target supply and market potential supply are estimated to be 3.97 and 4.11 million tCO2. •The potential of replacing natural gas with hydrogen in fuel cells was investigated.•Balance between supply and demand was simulated considering hydrogen vehicle use.•Hydrogen production using surplus electricity and municipal waste was simulated.•Surplus electricity can be expected in target and market potential supply scenarios.•Up to 16.8% CO2 reduction can be expected in the market potential supply scenario.