WASHINGTON — In October, Energy Secretary Steven Chu pledged that solar panels and a solar water heater would be installed on the White House roof before the start of summer.

Jimmy Carter installed solar panels on the White House roof in 1979. Now, many months after President Obama promised to reinstate solar panels on the white house, they are still no where to be seen. Now, summer is almost over, the 2012 election campaign is well under way, and there are still no solar panels on the White House roof.

Why? That's a mystery.

The Energy Department will say only that the project is mired in the "competitive procurement process." Spokeswoman Joelle Terry declined to go into details of the holdup. Questions about when that process might be completed also were rebuffed. So were queries about the projected cost of adding the panels and where the panels would be located.

The National Park Service, which put solar panels on White House outbuildings during the administration of President George W. Bush, said it couldn't comment on why the previous installation was completed more quickly. It directed questions to the White House, where press spokesman Clark Stevens deferred to the Department of Energy, where spokeswoman Terry stuck to her original statement.

Not even Solar Design Associates, which according to the magazine Solar Today installed the previous panels, was willing to comment. A search of the government contracting website USASpending.gov did turn up a $10,000 contract, awarded in January, to Overly Manufacturing Co. That contract was to "support the contractor" for the photovoltaic system and "ensure that the integrity and warranty of the White House roof is maintained."

No one was willing to reveal the details of the formal government bidding proposal, which was not posted online.

Solar panels atop the White House, America's most famous government building, have long been a policy statement. President Jimmy Carter installed 32 in 1979 when an Arab oil embargo spiked fuel prices.

"No one can ever embargo the sun or interrupt its delivery to us," Carter said at the installation ceremony, having never seen the episode of "The Simpsons" where Mr. Burns blocks out the sun with a giant disk.

President Ronald Reagan removed the panels in 1986. Then came the National Park Service-directed installation during the most recent Bush administration. Those panels went on a maintenance building and on the president's cabana to heat water for the outdoor White House pool.

Chu announced that panels would be going up on the White House itself at the GreenGov Symposium, which was described on its website as "a three-day educational event to identify opportunities around greening the Federal Government." It was sponsored by the White House Council on Environmental Quality and held at George Washington University in Washington Oct. 5-7, 2010.

"As we move toward a clean energy economy, the White House will lead by example," Chu said then when he promised that solar panels would be returned to the White House roof. "It's been a long time since we've had them up there."

The project was intended to be part of the Energy Department's larger SunShot Initiative to make solar technology cost-competitive.

Solar power is one of the staples of the growing alternate energy sector. Both commercial buildings and homes are incorporating the technology, though it still makes up only about 1 percent of the energy produced by alternative fuels in the U.S., according to the U.S. Energy Information Administration.

A spokesman for the organization 350.org, named after an atmospheric target of 350 parts per million of carbon dioxide recommended by some scientists to ward off the "greenhouse effect" blamed for global warming, expressed disappointment that the solar panels hadn't yet made it to the roof of the White House.

"This isn't rocket science. Hammer it in, make a few connections — you're good to go," said Jamie Henn, the group's spokesman. "If the first lady is going to go out and get her hands dirty planting her garden, then it's up to the president to do some home improvements as well."

His group has been a leading proponent of heads of state adding solar panels to their residences.

"The administration needs to do more to show that they're serious about moving clean energy forward," he said. "There's no better way of doing that than getting on the roof of the White House and proclaiming that there shouldn't just be solar panels there, but on rooftops all across America and around the world."

While it may be a little more complicated than Henn jokes, two other heads of state have installed solar panels on their official residences.

In the Maldives, 48 panels went up on the Mulee Agee Palace in 2010, within days of Chu's appearance at the GreenGov Symposium. President Mohamed Nasheed helped install the solar panels himself and pledged to make the island nation carbon-neutral by 2020. The Maldives, which sit off the tip of India, are vulnerable to the rising seas associated with climate change. How vulnerable? The highest point is less than eight feet above sea level.

In New Delhi, 64 solar panels were installed on the auditorium at Rashtrapati Bhavan, home of India's president, Pratibha Devisingh Patil. One hundred solar-powered streetlights also illuminate various sections of the Rashtrapati Bhavan compound, which boasts of five electric vehicles that are charged with solar power and leave no carbon footprint, according to the government's website. India began greening the presidential compound in 2008 as part of the Roshni initiative to develop green urban habitats.

Biron reports for Medill News Service, the Washington program of Northwestern University's Medill School of Journalism.