...and, I thought it was difficult to begin with.
Wind is not a good energy source: There isn't that much energy in the wind to begin with and its intermittency makes it a loser. That stated, I thought that improvements in storage capability might make wind marginally feasible. Looks like that will not be the case for the foreseeable future.
Solar is a little better but not by much. It is an excellent source of direct power in remote, dessert areas but not for supplying the electrical grid.
A full discussion of the issues with solar and wind is here. The article concludes:
It is very unlikely that any grid storage solution (other than PHS where feasible) could ever cover the intermittency of high penetration utility scale wind and solar. Utility voices (like RWE and E.ON) charged with making electricity grids work seamlessly and reliably despite ever increasing renewable intermittency burdens are only starting to be heard. Those voices are negative. It may not be until some grid goes dark because of intermittency (as increasingly uneconomic flexed conventional generation is shut in Germany and UK) that the general public will understand. Germany, UK, and California seem determined to run this unfortunate experiment for the rest of us. One or more appear likely to succeed soon in experimentally proving the grid instability ‘blackout’ hypothesis. The question is mainly when, not if.