An aircraft comprising: a gas turbine engine (20, 120) including a compressor section (24, 122), the compressor section (24, 122) including a plurality of compressor bleeds (102, 104, 106, 108); an environmental control system having an air input configured to receive pressurized cabin air; an intercooler having an input and an output; a selection valve configured to selectively connect at least one of said plurality of compressor bleeds (102, 104, 106, 108) to said intercooler input; and at least one auxiliary compressor (160, 162, 234, 238) connected to said intercooler output, wherein an output of the at least one auxiliary compressor (160, 162, 234, 238) is connected to said ECS air input; and a controller configured to receive contemporaneous operational data, calculate minimum configuration requirements to satisfy environmental demands, and transmit calculated configuration requirements to at least said selection valve to achieve a desired pressure and temperature for the pressurized cabin air downstream of said at least one auxiliary compressor (160, 162, 234, 238); said selection valve selectively connects at least one of said plurality of bleeds (102, 104, 106, 108) to provide air to said intercooler at a pressure below a desired pressure of said ECS air input; at least one of said at least one auxiliary compressors (160, 162, 234, 238) includes an electric motor (164, 166) configured to drive rotation of the corresponding auxiliary compressor (160, 162, 234, 238); and said controller is configured to control the electric motor (164, 166) and the selection valve to achieve the desired pressure and temperature for the pressurized cabin air downstream of said at least one auxiliary compressor (160, 162, 234, 238). a gas turbine engine (20, 120) including a compressor section (24, 122), the compressor section (24, 122) including a plurality of compressor bleeds (102, 104, 106, 108); an environmental control system having an air input configured to receive pressurized cabin air; an intercooler having an input and an output; a selection valve configured to selectively connect at least one of said plurality of compressor bleeds (102, 104, 106, 108) to said intercooler input; and at least one auxiliary compressor (160, 162, 234, 238) connected to said intercooler output, wherein an output of the at least one auxiliary compressor (160, 162, 234, 238) is connected to said ECS air input; and a controller configured to receive contemporaneous operational data, calculate minimum configuration requirements to satisfy environmental demands, and transmit calculated configuration requirements to at least said selection valve to achieve a desired pressure and temperature for the pressurized cabin air downstream of said at least one auxiliary compressor (160, 162, 234, 238); said selection valve selectively connects at least one of said plurality of bleeds (102, 104, 106, 108) to provide air to said intercooler at a pressure below a desired pressure of said ECS air input; at least one of said at least one auxiliary compressors (160, 162, 234, 238) includes an electric motor (164, 166) configured to drive rotation of the corresponding auxiliary compressor (160, 162, 234, 238); and said controller is configured to control the electric motor (164, 166) and the selection valve to achieve the desired pressure and temperature for the pressurized cabin air downstream of said at least one auxiliary compressor (160, 162, 234, 238).