Gov. Paul LePage’s nominee to lead the Maine Department of Environmental Protection pledged Monday to work collaboratively and transparently to protect the state’s natural environment, which he called “our most valuable resource.”

Paul Mercer, a senior administrator at Maine Maritime Academy who has worked extensively in the private sector on energy and waste issues, received a legislative committee’s unanimous endorsement Monday after a congenial nomination hearing.

If approved by the Maine Senate, as expected, Mercer would take over an agency that has often been at the center of LePage’s push to rein in regulations he views as harmful to businesses, as well as his administration’s numerous battles with environmental groups.

Yet with his private sector experience, Mercer would mark a departure from the attorneys, policy advisers and longtime state employees who have led the DEP for much of the past two decades.

An engineer and Maine native, Mercer serves as the assistant to the president of Maine Maritime Academy – his alma mater – on sustainability initiatives. He is a former associate professor and chairman of the school’s engineering department and has worked on renewable energy, biomass energy and power generation in the private sector.

Mercer told members of the Legislature’s Environment and Natural Resources Committee on Monday that much of his 40-year career was in fields “bounded by procedures, codes and regulatory requirements” and that “personnel and environmental safety have been the core of every job I have ever had.”

He also pledged, as commissioner, to “work collaboratively with constituents and stakeholders” in a way that promotes innovation while protecting the environment.

“The natural environment, land, air and water of the state of Maine is our most valuable resource,” Mercer said. “We must protect it and do so in such a manner that we can maintain and support existing businesses and industry. We must promote and encourage new and innovative businesses and focus on a sustainable economy.”

He would replace Patricia Aho, who stepped down in August after a four-year tenure during which she clashed with environmentalists and was the subject of a Maine Sunday Telegram investigation that found the former lobbyist weakened programs and opposed laws that would have affected former clients.

There is no shortage of issues facing the next DEP commissioner. LePage has had a rocky relationship with the state’s growing renewable energy industry. The department plays a key role in reviewing controversial proposals for commercial wind power projects.

In addition to regulating air and water emissions from industry, the DEP will have to implement new federal requirements on ground-level ozone and carbon pollution from power plants. The Legislature is also reviewing the state’s solid waste management regulations.

Before joining the faculty at MMA in 2006, Mercer founded two firms – Bay Engineering of Searsport and Northeast Engineering of Bucksport – that provided engineering and consulting services to projects inside and outside of Maine. Mercer has experience with everything from waste-to-energy systems and biomass fuels to livestock manure, and he is approved by the Maine Public Utilities Commission as an independent auditor of renewable energy credits.

One high-profile local project in which he was involved was the conversion of then-Champion Paper mill in Bucksport to natural gas in the early 2000s.

Although Verso Paper closed the Bucksport mill last year, the conversion was credited with lowering costs and helping it remain competitive.

Rep. Richard Campbell, a Republican who represents Bucksport and Orrington, was the only lawmaker to ask Mercer a question during the nomination hearing. Campbell asked Mercer what role he anticipated playing in helping Bucksport capitalize on the natural gas and power lines and other infrastructure already in place as it seeks to redevelop the mill site.

Mercer, who lives in nearby Penobscot, said he was proud that Bucksport residents accepted that papermaking was unlikely to return to town and for embracing new options. He met with the owners of the former mill property and acknowledged “they do have some challenges in front of them.”

“I do believe the new owner has a commitment for redevelopment and I am very, very hopeful that something will come from that and all of the collaborative efforts of the community to make that happen,” Mercer said. “I think we should work as close with them as we can to make sure that we stay within the laws and statutes of the state while helping them get into a new era in that town.”

Several people testified in support of Mercer’s nomination; no one testified against him.

Mercer’s current boss, Maine Maritime President William Brennan, called him “my closest confidant in managing the affairs of the college” for the past six years. Brennan, a commissioner under a former governor as well as a former head of the National Oceanic and Atmospheric Administration, was unable to attend Monday’s hearing because he has been aboard the academy’s training ship, but wrote a letter to the committee saying Mercer has the skills and intellect to balance the “competing interests” at the DEP.

“He has an uncanny ability to speak truth to power convincingly and without alienation,” Brennan said. “You will find Mr. Mercer to be knowledgeable and confident. You will find him to be flexible and understanding in various positions, firm when firmness is called for and courteous and pleasant to work with.”

Avery Day, the interim DEP commissioner who is LePage’s senior adviser on environmental and natural resources issues, testified that Mercer “has the skills, background and, perhaps most importantly, the temperament to successfully lead” the DEP.

The Maine Senate could vote on Mercer’s nomination as early as this week.

Under a financial order issued by LePage last year, the head of the DEP and other commissioners make just shy of $128,000 a year in salary plus benefits.