Abstract: The present invention relates to an energy distribution system (20) for an aircraft with at least two electrical powertrain units, each comprising a propulsion unit (1) powered by energy storage units (13) each configured to supply a first direct current, DC, voltage. The energy distribution system (20) comprises at least one converter unit (25) configured to energize a DC bus (16) having a lower DC voltage than the first DC voltage provided from each respective energy storage unit (13), each converter unit (25; 35) comprises a DC/DC converter arrangement (21) configured to convert the first DC voltage from at least one energy storage units (13) to a second DC voltage on the DC bus (16), and a DC bus battery (22) with a nominal operating DC voltage of the second DC voltage.