"Hard" means you have to actively manage your grid, instead of just checking up on it every fifteen minutes or so.

Yes, you need balancing capacity that can be ramped up quickly. This is available on a Europe-wide basis these days. In the medium term, e.g. ten years with renewables ramping up as fast as possible, you have plenty of balancing capacity because -- guess what -- all those fossil plants you are displacing still exist, and you can run them to plug the gaps.

To eliminate those fossil plants entirely is perhaps harder, but we don't need to do that in the medium term.

_{It is rightly acknowledged that people of faith have no monopoly of virtue - Queen Elizabeth II}