Complex sentence: Due to increasing demand, as well as increasing capacity due to the regulation of Göta älv, another five were then built, and by 1921 Olidan carried a total of 13 turbines.
Split into simpler sentences: Due to increasing demand, as well as increasing capacity due to the regulation of Göta älv, another five were then built. By 1921, Olidan carried a total of 13 turbines.