  In this paper, a novel approach to define the optimal bidding of
renewable-only virtual power plants (RVPPs) in the day-ahead, secondary
reserve, and intra-day markets is proposed. To this aim, a robust optimization
algorithm is developed to account for the asymmetric nature of the
uncertainties that characterize the market prices, as well as the energy
production of the RVPP stochastic sources and flexible demand consumption.
Simulation results show increased RVPP benefits compared to other existing
solutions and demonstrate the potential of renewable sources to further
increase their economic competitiveness. The simplicity of the implementation,
the computational efficiency, and the flexible robustness are also verified.
