They really need large batterry buffers fast, still it is kind of ironic that green energy that is not constant produces so many problems.
As long as the production and the load can not be controlled it makes a lot of sense for it to be buffered - given the primary source of energy is free.
There are solutions to actually store high amounts of energy apart from batteries... like pumping water uphill into artificial reservoirs (requires a suitable topology).
Another way around the problem would be to synchronize loads (that allow it, maybe already containing buffers) with production. The prices however might be less predictable, such models therefore frowned upon by both utility and customer.