The units represent over 11,000MW of electric generating capacity, the company said.
Under the contract, Shaw will provide engineering, procurement and construction management for modern air quality control technologies.
With these technologies, the company would help FirstEnergy reduce emissions including sulfur dioxide, mercury, particulate and hydrogen chloride.
Shaw’s Power Group president Eli Smith said, "With proven technical expertise and project execution capabilities, Shaw is able to help clients meet regulatory requirements, as well as provide safe, reliable electricity in an environmentally responsible way."
The group, which employs about 25,000 people, had revenues of $5.9bn in 2011.
