The Soubre hydroelectric power station has an installed capacity of 275MW.
In February, Yapi Merkezi and Mota-Engil Africa were hired for the project.
The signing of the deal will enable the contractor to kick off works by January next year.
The re-introduction of toll stations is, however, likely to face huge legal encounters.
Kenya has recently embarked on projects aimed at opening up the northern corridor.
Bechtel has been picked to build the Mombasa-Nairobi Expressway.
Engineered Material Arresting System is cheaper than the traditional technique.
The project has faced numerous challenges including hiccups in relocating utility lines.
The investors have urged Nakuru County to revive the project.
The facility is expected to open up the Northern Kenya tourism belt.
Talks are underway for China to fund a new highway and rail extension.
The Chinese-funded Orpower 22 power plant will take 17 months to complete.
Bedsitters will rent for Sh3,200 per month on a 30-year rent-to-own plan.