Yup... if designed properly, green energy can fill a full baseline of energy now (would have to include hyrdo/geothermal), but peaks and the subsequent valleys are the real issue in transferring the large portions of the grid to renewables. There are sections of the peaks and valleys that can be handled with our current storage technologies. Some peaker plants are being replaced with battery storage in areas that have an excess of available energy during other times. California and Australia have had some large successes, but there isn't the bandwidth yet with the current raw materials to implement it at a scale that is need to to transition to full renewables via battery technology. Which is why pumped hydro storage is by far the huge leader in energy storage, and will be key for a large transition. It can be naturally unpopular (simply because of the type of terrain it requires), but it is simple and relatively efficient.