This week, Europe’s electric transmission lobby announced that oven, microwave, and alarm clocks across the continent were no longer six minutes slow. How did they get back the lost time? By resolving a grid dispute between Serbia and Kosovo, and running the continental grid at a slightly higher frequency than normal.
That’s because clocks that are connected to an outlet often tell time by counting the the rate of the electrical current, and on the Continental Europe Power System the clocks expect an average frequency of 50 Hz. But between mid-January 2018 and early March, a grid dispute between Serbia and Kosovo resulted in 113GWh of unmet demand from Kosovo. Since Kosovo is part of the Continental Europe Power System, the unmet demand on the 25-country system led to a system-wide decline in frequency to an average frequency of 49.996 Hz. That meant that clocks were counting down minutes too slowly, and over 3 months, connected clocks around the continent lost six minutes.
Last month, the European Network of Transmission System Operators (ENTSO-E) publicly admonished Serbia and Kosovo for not properly balancing their grids according to previous agreements. “This average frequency deviation, that has never happened in any similar way in the CE [Continental Europe] Power system, must cease,” the group wrote. “ENTSO-E is urging European and national governments and policymakers to take swift action.”
Two days later, on March 8, the Transmission System Operators (TSOs) from Serbia and Kosovo confirmed that they were back to balancing their grids appropriately.
Last week, ENTSO-E announced that it had restored the lost 6 minutes to clocks around the continent by maintaining a slightly-higher-than-normal average frequency of 50.01 Hz for a month. The missing energy was put back into the system with the collective help of the 25 member countries, which “carried out a compensation programme to restore the situation back to normal.”
“One of the effects is notably that the digital clocks geared by electric frequency are now back on time,” ENTSO-E wrote. That is, as long as you oven-clock owners within the Continental Europe Power System didn’t change your slow clocks to the correct time a month ago. If you did, now you could be six minutes fast. But at least you’re less likely to be late now.