A vehicle includes an internal combustion engine operatively disposed therein. The engine generates exhaust gases. The vehicle further includes an alternator operatively connected to the engine. The alternator produces DC power. An ultracapacitor is operatively connected to the alternator to receive electrical energy therefrom. The vehicle still further includes an exhaust gas treatment system operatively connected to the engine to receive exhaust gases therefrom. The exhaust gas treatment system includes an electrically heated catalyst (EHC) device electrically connected to the ultracapacitor to selectively heat a catalytic exhaust system component. The ultracapacitor stores energy converted by the alternator from vehicle kinetic energy and releases the stored energy to heat the EHC.