Russia’s Energy Ministry has begun enforcing temporary blackouts in Crimea to prevent overloading the region’s energy supply system, the Interfax news agency reports.

Over 100,000 Crimean residents suffered a two-hour power outage on Monday, which authorities attributed to the heavy use of air conditioners on the peninsula, where temperatures are nearing 40 degrees Celsius.

The blackouts have particularly hit Crimea’s southern coast.

Since Russia annexed the Black Sea peninsula in March 2014, Crimeans have suffered repeated power shortages. In November 2015, electricity pylons supplying Crimea with energy were blown up in Ukraine, plunging the peninsula into weeks of darkness.