The graphs shows hourly data on the German average electricity consumption (in MW) and wind and solar energy production for the year 2014.

Zoom into some week, to see the quite regular in-day cycle of electricity demand and solar energy production.

Wind energy production does not seem to follow such regular cycles. Low and high wind production is relatively persistent of longer periods of time.

If you zoom in on January, you see that there can be large periods with very little wind and solar production (e.g. from 13. to 25. Jan. with a small peak inbetween). The current German storage capacity (mostly pump-storage) cannot even store an hour of typically German electricty consumption. This suggests that very large convential backup capacities are still needed to guarantee secure electricity supply even if wind and solar would be extended further. Even so off-shore wind blasts more steadily than on-shore wind, and there may be a storage revolution on its way, the need for large convential backup capacities probably won’t go any time soon.

Data sources: ENTSOE (for consumption), German transmission network operators (Amprion, Tennet, 50Herz, Transnet BW) for solar and wind production. Note that wind and solar production data are to a certain extend estimates by the network operators.