This disclosure generally relates to power generation methods and systems based on gas turbine engines, and particularly to mobile and adaptive power generation systems and methods based on gas turbine engine for supplying mechanical and/or electrical power for fracturing operations at an oil wellsite. Various systems, platforms, components, devices, and methods are provided for flexibly and adaptively configure one of more gas turbines, hydraulic pumps, and electric generators to support both fracturing and electric demands at a well site. The disclosed implementations enable and facilitate a mobile, adaptive, and reconfigurable power system to provide both mechanical and electric power for hydraulic fracturing operation.