This study proposes a curtailment-minimization model to investigate the potential of urban bio-waste to provide flexible electricity to a wind and solar powered Amsterdam. The transition to solar and wind as primary sources of renewable energy is hampered by their intermittent nature. Being controllable, biomass energy holds the potential of providing both renewable and flexible power. For the transformation from urban bio-waste to electricity, a coupled gasifier and solid oxide fuel cell (SOFC) unit was used. An islanded microgrid for the residential area of Amsterdam was investigated on the basis of an average year, both in terms of weather and electricity consumption. The study aims at finding the optimal sizing of each component to provide sustainable and secure electricity supply. Security of electricity supply was guaranteed by ensuring a net positive daily energy balance while minimizing the total surplus energy to be curtailed during the year. All organic municipal solid waste (MSW) available was used representing 39% of the yearly electricity demand of Amsterdam; PV panels (20%) and wind turbines (41%) covered the remaining share. To this end, optimal PV and wind capacities of 186 MW and 165 MW were estimated, representing respectively 16.9% and 94.0% of the total potential capacity of Amsterdam. In this study, the use of urban bio-waste is proven to bring flexibility to the energy system: using more biomass allows lower curtailment values.