Editorial: Towards 100% Renewable Energy System.

The penetration of variable renewable energy (VRE) resources (wind and solar Photovoltaic (PV)) is increasing rapidly across the world and in many regions by capacity is the dominant new generation that is connecting to the grid. This is part of an accelerating trend that dates back several decades. With this rapid increase in VRE there has been a trend in the popular press and in parts of the academic literature to claim that 100% renewables is not only a desirable end point but is relatively easily achievable – there is also a totally counter narrative that says you cannot possibly have a grid with very high penetrations of VRE and certainly not 100%. Neither of these narratives are useful or constructive. It is certainly technically possible to get to 100% VRE grids but is far from easy and certainly with our current technology and societal expectations around electricity it would be very expensive. A more balanced and correct statement would be "it is possible to get to 100% VRE grids but there are many challenges that need to be solved" and this is the subtext for this special section on the development of a 100% Renewable Energy System". [ABSTRACT FROM AUTHOR]