Orion Power has agreed that it will buy seven power plants from the Duquesne Light Company for a total sum of $1.7 billion.

This deal is Orion’s fourth purchase in the past year, and, if it is approved, it would double Orion’s holdings to 5230 MWe.

The sale is contingent on a power-plant swap taking place between Duquesne and FirstEnergy of Ohio. The two companies have agreed to trade stakes in the five power plants that they jointly own so that each will have the sole ownership of several power plants.