Energy that is only intermittently available poses a big problem for machinery and equipment that depend on a steady feed. From Irina Slave at oilprice.com:
Earlier this month, something happened in Europe. It didn’t get as much media attention as the EU’s massive funding plans for its energy transition, but it was arguably as important, if not more. A fault occurred at a substation in Croatia and caused an overload in parts of the grid, which spread beyond the country’s borders. This created a domino effect that caused a blackout and prompted electricity supply reductions as far as France and Italy. The problem was dealt with, but it’s only a matter of time before more problems like this occur—the reason: the rise of renewables in the energy mix.
Bloomberg reported on the incident citing several sources from Europe’s utility sector. While no one would directly blame the blackout and the increased risk of more blackouts on renewables, it is evident that Europe’s change in the energy mix is raising this risk.
The problem has to do with grid frequency. Normally, it is 50 hertz, Bloomberg’s Jesper Starn, Brian Parkin, and Irina Vilcu explain. If the frequency deviates from this level, connected equipment gets damaged, and power outages follow. The frequency is normally maintained by the inertia created by the spinning turbines of fossil fuel—or nuclear, or hydro—power plants. With Europe cutting its coal and nuclear capacity, this inertia declines as well, exposing the grid to frequency deviations.
“The problem isn’t posed by growing green electricity directly but by shrinking conventional capacity,” the chief electricity system modeler at Cologne University’s EWI Institute of Energy Economics told Bloomberg.