Enel SpA plans to spend €70 billion, equivalent to $83 billion, expanding its presence in wind and solar power in the coming decade, seeking to cement its position as the world’s largest renewable energy producer outside China and to capitalize on the shift to green energy. The Italian utilities company was an early mover in renewable energy, giving it—along with Iberdrola SA and NextEra Energy Inc.—an edge amid increasing global demand for low-carbon power, and putting the trio among the world’s most valuable energy…