"100% renewable" in Denmark usually means a mixture of Danish wind and Swedish/Norwegian hydro. The wind power is highly variable so only fills Danish energy needs on some days, but Denmark has the fortune to be near very large hydro installations further north, which are relatively easy to flex, and provide the remainder via high-capacity links. (For customers not needing "100% renewable", the load is also managed using Denmark's thermal power plants and Sweden's nuclear plants.)

This somewhat unusual arrangement does mean that wholesale spot electric prices are hugely variable, ranging from near-free on high-wind days, to around €0.025/kWh on normal days, to above €0.04/kWh on low-wind days [1]. But you can reduce that risk through long-term contracts.

[1] Forecast for the coming week (look at the DK1/DK2 rows): http://www.nordpoolspot.com/

Yes, for the most part.