Nuclear power currently supports the goals of the European Union low-carbon society by being a dependable source of energy, while emitting no CO2. In the future, more flexible nuclear systems could enable wind to achieve a 50% share of the renewable contribution to the energy mix. Small and medium-sized reactors (SMRs) could provide firming power generation to back-up the supply from renewable resources and follow-load. This study involves the hypothetical combination of an off-shore wind farm and a SMR, operated together as a virtual power plant (VPP). Results using wind data from the North Sea indicate that the combination results in 80% less wind power variation to the grid, effectively creating a virtual baseload power plant. This gain comes at the loss of 30% SMR capacity utilization. The research identified that the reduction of 1000 MW off-shore wind farm variability was best achieved with 700 MW SMRs using 100 MW modules. In demand-following mode the VPP could maneuver output to improve synchronization with demand by 60-70% over a wind-only system. Power variability was indifferent to the SMR module size. The VPP could not reduce 100% of the wind variation, as additional balancing measures (e.g., smart grid, storage, and hybrid-nuclear systems) are still needed. (C) 2012 Elsevier Ltd. All rights reserved.