Integration of Renewable Energy Sources: A Review of Hybrid and Aggregated Energy Systems

Abstract

Among the renewable energy sources (RESs), solar and wind feature steadily decreasing costs of electricity, today competitive with fossil-fuel-based power plants. However, the intermittency of their output makes them not suitable as stand-alone technologies for off-grid installations, and large share of these intermittent renewables cannot be supported by electric grids. The problems caused by the intermittency of the power output can be smoothed by integrating non-dispatchable RESs with energy storage systems and/or different types of RESs as well as dispatchable power generation units. These “aggregated systems” are gaining considerable interest and, depending on the application, are called with different names: “virtual power plants”, “microgrids”, “multi-energy systems”, “energy districts”. Moreover, improved performance can be achieved adopting “hybrid systems” employing different renewable sources and/or technologies in the same energy conversion process. This chapter provides an overview of the most interesting options to integrate renewable energy sources.