Everything you read about wind and solar PV power (unless it is from the raving lunatic I love wind at any cost green party manifesto) says that every wind turbine and PV solar panel needs 100% backup from either coal, gas or nuclear (ie the reliable sources) because without being able to store energy from those sources to cover windless and cloudy days (more than one day, in other words medium term storage ) they are severely handicapped. On a lightly clouded day PV solar can be reduced to less than 10% of rated output, and below about 30mph wind turbine output drops off very rapidly. Germany has less wind than UK (UK is one of the windier places, most suitable for wind turbines) but to placate the greenies Germany has installed lots of turbines, and they produce over a year about 18 % of their rated (installed) capacity, UK even with our more steady wind averages a heady 21% of installed capacity actually produced. I really feel sorry for the people who have the ever more complicated job of integrating renewables without any storage to level output into our grid, it's like trying to run a business where often on some days most of your workers may not turn up and the ones that do will often be found sleeping at their desk, you would soon be advertising for 'reliable' staff, and that is when the agency sends around the fossil and nuclear workers, and boy, would you be glad to employ them (even though some of them smell and others wear a lead overcoat).