“There is not a contradiction between economic grown and sound environmental practices,” Obama said. He said the stimulus can be a “down payment on things we should have been doing 10 or 20 or 30 years ago.”

To help meet the broader goals, the Energy Department and Environmental Protection Agency could undergo a transformation.

The Energy Department’s primary purview is managing the country’s nuclear weapons programs. But Obama says he wants to spur development of a vast array of cutting-edge technologies still unproven on a commercial scale, such as capturing and storing the carbon emitted when coal is used to generate electricity and inventing “next generation” biofuels. Obama said pursuit of clean energy sources would become “the guiding principle of our Department of Energy.”

Supporters say Chu, 60, a Nobel Prize-winning physicist, is well-equipped to lead such a mission, while his scientific background also equips him to manage the agency’s current portfolio. Obama said the appointment “will signal to all that my administration will value science.”

While running the 4,000-person Berkeley National Laboratory — one of the most prestigious scientific institutions in the world — Chu initiated new programs aimed at researching renewable and alternative energy. He strongly backs efforts to reduce greenhouse gas emissions.

“What the government can do, more than anything, to stimulate innovation, is give a long-term stable price signal for carbon and renewables,” Chu said earlier this year. “Regulation stimulates technology . . . renewable energy offers immense opportunities, but we need to put a price on carbon to realize them.”

The EPA’s role also could expand dramatically. If Congress is slow to pass a global warming bill, the EPA might try to regulate greenhouse gases on its own using authority under the Clean Air Act (PL 101-549). Addressing climate change will come on top of traditional environmental problems like protecting air and drinking water quality. Obama may ask Congress to boost the agency’s funding after significant cutbacks under the Bush administration.

Jackson, commissioner of New Jersey’s Department of Environmental Protection from 2006 until she became Democratic Gov. Jon Corzine ’s chief of staff this month, previously worked at EPA for 16 years.

As a trained chemical engineer, Jackson combines a scientific background with administrative experience. She is generally well respected in New Jersey, with environmentalists crediting her with strong initiatives that often overcame Corzine’s reluctance.

However, detractors said she did not do enough to alleviate the state’s myriad of environmental problems, including a legacy of toxic waste sites that have not been cleaned up for decades.

Jackson, 46, will face the challenge of leading an agency that has been accused under the Bush administration of lacking transparency and of taking marching orders from the White House that put politics ahead of science.

Browner, who turns 53 Tuesday, was the longest-serving administrator in the EPA’s 38-year history. She will take on the new role of assistant to the president for energy and climate change, and will be expected to coordinate energy and climate policy across all the cabinet agencies.

As EPA chief, she pushed for new air quality standards for smog and soot in the face of fierce industry opposition during her tenure. Browner has been a vocal advocate of a system to cap greenhouse gas emissions and allow polluters to trade credits in the marketplace.

The role of Sutley, 46, as head of the White House Council on Environmental Quality remains somewhat unclear. Traditionally, the position has coordinated environmental policy in the White House, but Browner’s new position would seem to take the lead role in setting policy.

The Obama picks appear to synchronize well with the views of the key figures in Congress who will oversee the drafting of climate change legislation next year, including Boxer and House Energy and Commerce Chairman Henry A. Waxman , D-Calif. Both Californians have strong environmental records in Congress and have pushed for the tightest emissions regulations possible.

Even some Republicans offered praise for the selections.

“The incoming administration’s choice of seasoned energy and environmental advisors demonstrates the seriousness with which the new president takes the challenges facing the country in simultaneously tackling climate change and energy security,” said Sen. Lisa Murkowski of Alaska, who is set to become the ranking Republican on the Senate Energy and Natural Resources Committee, which will take up Chu’s nomination.

But not everybody was happy with the picks. Sen James M. Inhofe of Oklahoma, the Senate Environment panel’s ranking Republican and the leading congressional skeptic of man-made global warming, criticized the choice of Browner.

“She is a proud liberal who has long advocated an environmentalist agenda that would drive-up energy costs on families and put thousands of Americans out of jobs,” Inhofe said. “At a time when the economy is already suffering, it will be interesting to see how President Obama will reconcile what seems to be conflicting agendas in the White House.”