A method and system are disclosed for co-production of olefins and electric power. The method includes determining a separation level, separating a hydrocarbon feed into a light fraction stream and a heavy fraction stream based on the determined separation level; generating electric power from the heavy fraction stream; and cracking the light fraction stream in a pyrolysis unit to produce an effluent comprising olefins. The separation level may be based on olefin production requirements and electric power requirements or specific split of the hydrocarbon feed to be utilized for power generation and olefin production.