The paper is about short periods of a day when renewables are meeting more than 100% of demand. If that broke the grid then there would be little future in bui

The paper is about short periods of a day when renewables are meeting more than 100% of demand. If that broke the grid then there would be little future in building out wind and solar beyond a small fraction of energy. The paper demonstrates it's not a problem, so further progress to making all of the grid's energy clean can continue.