A former Pembina Institute executive whose appointment to the board of the Alberta Energy Regulator drew criticism from the United Conservative Party has resigned after what he calls a "smear campaign" orchestrated by members of the incoming government.

In his letter of resignation, which he released to the media on Monday, Ed Whittingham says he realizes his decision to step down might be symbolic, "given the new government's well-publicized campaign to misrepresent my record and fire me from the AER's board for being a 'cat among the pigeons.'"

UCP Leader Jason Kenney is to be sworn in as premier Tuesday and has promised that one of his first acts in the job would be to fire Whittingham.

He has accused Whittingham of committing "economic sabotage" against the province's oil and gas industry by supporting and abetting groups seeking to landlock it.

After Whittingham was appointed by the NDP on February 12, UCP house leader Jason Nixon held a news conference denouncing his selection and calling him an anti-oil activist.

Whittingham strongly rejects the way his opponents have characterized his stances related to energy development.

"Under my long tenure at the organization, Pembina never intervened in any regulatory process to oppose any pipeline," he said. The Pembina Institute is an environmental think tank that provides research on oil and gas and sustainable energy.

"My views on responsible energy development are well documented in many op-eds and blogs readily available online, and are entirely consistent with safe, environmentally responsible development of oil and gas resources. I have maintained constructive and respectful relationships with Alberta's industry leaders and devoted my career to advancing solutions to the energy challenges we face."

He said that despite the facts, he has been the subject of an unprecedented smear job and that his character has been defamed.

Whittingham says he regrets that he will not have the chance to help the AER's board of directors carry out its "critical mandate of ensuring companies operate in a safe and environmentally responsible manner, within an effective and efficient regulatory system."

Whittingham also criticized the UCP's plan to scrap the 100 megatonne limit on oilsands development and put the brakes on the province's phasing out of coal-generated electricity.

He said these measures have driven environmental improvements and innovation, and help to give Canadians and the world more confidence that Alberta is doing its fair share to address climate change.

"I use the oilsands-flyover index. When was the last time we had a celebrity from Hollywood, like a James Cameron or a Neil Young, Leonardo DiCaprio coming up and saying bad things about the oilsands? It hasn't happened for a long time because we've been on the right track," he told CBC News.

Whittingham says he's worried that a weakening of Alberta's environmental laws under the UCP will be counterproductive to job creation and getting responsibly-developed Alberta oil to tidewater.

Telling 'the truth' is not a smear, UCP counters

"Mr. Whittingham and Pembina's agenda is clear: they want to shut down the Alberta energy sector. And it has been reported that they have taken $8 million in foreign money to fund their anti-oil, anti-pipeline agenda," Kenney's press secretary emailed in response to CBC News on Monday.

"Mr. Whittingham and Pembina have opposed every proposed pipeline project in recent memory, including Energy East, Keystone XL, Line 3 and the Trans Mountain expansion. What's more, they support Justin Trudeau's 'no more pipelines' law, Bill C-69. We reject the assertion that telling Albertans the truth about these facts amounts to a smear."

"Premier-designate Jason Kenney has been clear that our incoming administration is going to be relentlessly focused on a strong, assertive and strategic defence of our economy, our workers and our way of life. Getting pipelines built, fighting back against foreign funded special interests, and standing up for a fair deal in Canada are key priorities of our team. Mr. Whittingham's assertions on our emissions cap commitments are false, and we are pleased he has resigned."

Kenney himself kept it shorter on Twitter:

"It was gracious of Ed Whittingham to resign a day before we could fire him," Kenney tweeted.

"Our government will never appoint people like him who are avowed opponents of Alberta jobs. And we will stop all funding to groups engaged in economic sabotage against Alberta."