Lewis has 25 years of listed and private company boardroom experience, including as chief executive, chairman and finance director, the wood-chip firm said.
He has been involved in numerous areas of business, including strategic planning, growth management, IPOs or corporate governance.
Richard Spinks, Active's chief executive, said: "My co-directors and I welcome Frank to the board as non-executive chairman at this exciting stage in the group's development, and we look forward to drawing on his expertise in corporate governance and regulatory compliance as we continue to expand our existing international operations and implement some of the new business ventures that we have been developing over the past two years."
Earlier this month the company said it had secured two significant high-volume supply contracts for 2015.
The company is also further expanding its Ukrainian production capabilities, and is introducing a new wood chip product line.
The two supply contracts have been signed with Turkish medium-density fibreboard (MDF) manufacturer Yildiz Entegre and require Active Energy to deliver up to 300,000 tonnes of its hardwood wood chip, and up to a further 300,000 tonnes of its new line of softwood wood chip, in 2015.