From Energy Matters: Green Mythology: adding different types of renewables smooths output
A favourite assertion of renewables enthusiasts is that intermittent supply can be smoothed by simply adding different types of renewable resource. How often have you heard “If it’s not windy then we can use tidal instead”. I present a simple renewable supply model for the UK that has 20 GW of tidal, 13.6 GW of wind and 8.8 GW of solar for a total of 42.5 GW installed capacity. When everything is on this outputs a maximum of 22.2 GW of power (52.2% load). When everything is off that falls to 0.9 GW (2.1% load). Those contemplating engineering the UK grid along these lines must surely be mad.