Europe's largest nuclear reactor finally begins commercial output in Finland.

Finland's Olkiluoto 3 nuclear reactor, Europe's most powerful by production capacity, has started regular output after a delay of 14 years from the original plan. The reactor will help Finland achieve its carbon neutrality targets and increase energy security. The project was plagued by several technological problems that led to lawsuits, and experts have put its final price tag at around 11 billion euros ($12 billion) — almost three times what was initially estimated. Finland now has five nuclear reactors in two power plants located on the shores of the Baltic Sea, covering more than 40% of the nation's electricity demand.