Donald Trump claims to be the outsider, but the energy and environment transition teams are well stocked with people familiar with the inside of Washington. But in some cases the bench of Trump supporters with the necessary expertise is not deep for the large number of positions that need to be filled.

David S. Jonas, a partner at Fluet, Huber and Hoang who has written about nuclear non-proliferation issues, is helping the transition for the Energy Department. The majority of the department’s budget goes to managing the nation’s nuclear stockpile and cleaning up old military nuclear weapons development sites.

Jonas and other transition people have been reaching out to Republicans, even those who had signed a letter along with scores of other conservatives saying they would not vote for Trump. The Trump transition recruiters have dismissed that problem as long as the potential appointees had not voted for Hillary Clinton. Ideological differences do not appear to be an issue either. “Why now would he be ideologically pure about things?” said one person contacted. “For love or money, he would sleep with just about anything.”

At the top of the Trump transition teams are experienced hands. The president-elect’s organization has turned to Mike McKenna for advice on the Energy Department and David Bernhardt, former Interior Department solicitor general under President Bush, on the Interior Department.

“Both are smart, canny individuals who understand the nuances of the departments for which they’ve been asked to provide assistance,” Scott Segal, co-head of government relations at the legal and lobbying firm Bracewell, said in an email.

McKenna, who is president of the firm MWR Strategies and who worked for both the Energy and Transportation departments, has lobbied on behalf of Dow Chemical, Koch Industries, Southern, GDF Suez and TECO Energy.

Bernhardt, a partner at the law firm Brownstein Hyatt Farber Schreck, has represented a wide variety of clients on regulatory issues such as the Endangered Species Act but has not lobbied for corporations, though he has lobbied on behalf of the Westlands Water District.

In addition, Myron Ebell, head of energy and environment at the Competitive Enterprise Institute, had headed Trump’s transition team on the Environmental Protection Agency. Ebell has called fears of climate change are greatly exaggerated and has called many mainstream climate studies false.