Seth Gladstone and Food & Water Watch stated last month:

Mr. Moniz is a known cheerleader for exploiting our reserves of natural gas using a highly controversial and polluting practice known as hydraulic fracturing (“fracking”). His appointment to the DOE could set renewable energy development back years. If we pursue our fossil fuel addiction by expanding fracking, which Mr. Moniz will likely advocate, the oil and gas industry will thrive while true energy efficiency and renewable solutions languish. Our water, public health and climate would suffer.
And Michael Brune, Sierra Club's executive director, stated:
We would stress to Mr. Moniz that an "all of the above" energy policy only means "more of the same," and we urge him to leave dangerous nuclear energy and toxic fracking behind while focusing on safe, clean energy sources like wind and solar.
However, Frances Beinecke, president of the Natural Resources and Defense Council, statedMonday:
This is good news. [...] His background, coupled with his long history of constructive engagement with, and at, the Energy Department, will serve the American people well. We look forward to working with him to advance a clean energy future based on efficiency and renewable power.
Obama's choice to replace Lisa Jackson as the Environmental Protection Agency is Gina McCarthy. McCarthy has served for the past four years as the assistant administrator of EPA's Office of Air and Radiation where she has been referred to as Obama's "green quarterback."

She previously worked in government environmental posts, including as a regulator under then-Massachusetts Gov. Mitt Romney. She also headed Connecticut's Department of Environmental Protection and is seen as a pioneer in state-based cap-and-trade programs that seek to curtail greenhouse gas emissions. Eight years ago, McCarthy was instrumental in putting togetherRegional Greenhouse Gas Initiative the nation's first mandatory cap-and-trade program.

In her current post, she has been the point person to curtail air pollution from power plants, particularly toxic chemicals like mercury from coal-fired plants. She was also deeply involved in the move to more strictly control automobile tailpipe emissions. She is widely seen as more of a fighter than Bob Perciasepe, who has served as interim EPA chief since Jackson left. At the same time, she is not seen as quite so much of the in-your-face figure that Jackson was.

Coral Davenport reports:

If nominated, she’ll face a fiery confirmation hearing from Republicans on the Senate Environment and Public Works Committee. The panel’s ranking Republican, Sen. David Vitter of Louisiana, and senior Republican member John Barrasso of Wyoming hail from states where oil and coal production are big parts of the economy—and EPA regulations are viewed as straight-up job-killers.
The view of most Republicans, those who won't want to dismantle the EPA altogether, has long been, despite a Supreme Court ruling to the contrary, that the EPA has no business trying to control greenhouse gas emissions.

Gene Karpinski, president of the League of Conservation Voters praised her:

Gina McCarthy cares about progress not partisanship. She’s worked for administrations from both parties and made extraordinary progress protecting the air we breathe and defending public health. Republicans and Democrats easily confirmed Gina McCarthy as head of the EPA’s clean air division, and we hope they move swiftly to confirm her as head of the agency. We look forward to working with her to combat the climate crisis, protect our air and water, and advance chemical policy reform.
The NRDC also backed her, as did Fred Krupp at the Environmental Defense Fund, and Sierra Club's Brune said:
We welcome the nomination of Gina McCarthy to head the Environmental Protection Agency. Assistant Administrator McCarthy has a strong record of protecting the health and safety of millions of Americans by limiting dangerous pollution in our air and supporting programs that help get America's kids outside.
One group that has had big problems with the EPA recently is the American Coalition for Clean Coal Electricity. The president and CEO, Mike Duncan, said Monday:
We congratulate Assistant Administrator Gina McCarthy on her nomination to be the next EPA Administrator, and we hope for a more constructive working relationship with the EPA under her leadership. We hope that if she is confirmed she can put EPA on a more balanced path that recognizes America’s continued need for coal, and the importance of clean coal technology.
More constructive? In other words, ACEEE's question for her is along the lines of why can't you be more like Stephen Johnson, the EPA's second director under George W. Bush, who Naturemagazine in an editorial stated had displaced a "reckless disregard for law, science or the agency's own rules—or, it seems, the anguished protests of his own subordinates."