With increasing penetration of intermittent resources such as wind and solar, power system operations are facing much more challenges in cost effective provision of energy balancing and frequency regulation services. Enabled by advances in sensing, control and communication, the concept of Virtual Power Plant (VPP) is proposed as one possible solution which aggregates and firms up spatially distributed resources? net power injection to the system. This thesis proposes a coordinated control and bidding strategy for VPPs to provide energy balancing and grid frequency regulation services in electricity market environment. In this thesis, the VPP consists of two energy conversion assets: a Doubly Fed Induction Generator (DFIG)-based wind farm and a co-located Flywheel Energy Storage System (FESS). The coordination of the VPP is implemented through power electronics?based controllers. A five-bus system test case demonstrates the technical feasibility of VPPs to respond to grid frequency deviation as well as to follow energy dispatch signals. To enable the participation of VPPs in electricity market, this thesis also proposes an optimization based bidding strategy for VPPs in both energy balancing and frequency regulation service markets. The potential economic benefits of this bidding strategy are demonstrated under Denmark wholesale electricity market structure. Four case studies show the economic benefit of coordinating VPPs.