This includes the costs wind and solar power impose on the electricity system as a whole, not just the cost of the VRE-generated electricity supplied to the grid. [...] The second part of the study shows how the system-wide costs and benefits of add- ing wind and solar power to an existing electricity system are affected by the policies of provincial governments, the cost of electricity, the conventional generating assets already in place, and the structure of the electricity system. [...] The motivation for adding VRE, the existing mix of generating assets, the organ- ization of the electricity system, and the role played by provincial governments are examined in order to understand these differences. [...] However, demand for electricity varies over time according to the time of day, the day of the week, and season of the year, and there may be underlying longer-term trends.2 The minimum amount of electricity required by the grid—base load—needs to be supplied continuously. [...] For this reason, when discussing the impact of wind and solar power on an electricity system it is necessary to broaden the definition of “grid services” to include the “service” the grid itself contributes to the system as a whole.