Worley's move to take full control of maintenance group TW Power Services for $20 million will help protect the engineering group from market fluctuations and boost its renewable energy services, chief executive Chris Ashton said.

"It desensitises us to the capital investment cycle and gives us exposure to the operating cycle," Mr Ashton told The Australian Financial Review from his home in Houston, Texas. "Strategically, it's a powerful addition to the Worley group."