Methods and systems are provided for adjusting operation of a throttle turbine generator to enable improved canister purging. A pressure differential across an intake throttle may be harnessed to rotate a turbine coupled in a throttle bypass, the turbine in turn driving a generator to charge a battery. During low intake manifold vacuum conditions, the generator may be operated as a motor to rotate the turbine, and use a compressor effect of the turbine to purge fuel vapors from a fuel system canister.