Secretary of Energy Steven Chu, testifying to Congress in November. Evan Vucci/AP Photo

WOODSTOCK, Ga.- Newt Gingrich, who sealed his $2.50 gas promise by adding two large "Newt 2012? gas logos to his campaign bus, called today for the firing of President Obama's Secretary of Energy, Steven Chu.

Chu, testifying before a House subcommittee on Wednesday, was asked if he believed it was the administration's goal to lower gas prices. Chu said no, the goal was decrease foreign oil dependency.

Gingrich took off after Obama: "If he's really serious about helping the American people, having seen yesterday's testimony, he will fire Secretary Chu and get somebody who favors less expensive gasoline," Gingrich said.

President Obama, who gave his second speech on energy in just nine days, made an obvious jab at Gingrich and the other GOP contenders, saying he wanted to talk about real energy solutions instead of "phony election year promises on lower gas prices." The president called for an end to oil and gas subsidies.

Since Obama delivered an energy speech earlier in the month, Gingrich has made energy a larger part of his stump speech. Gingrich added a line at nearly every stop in Oklahoma and Georgia, mocking the president's suggestion that the U.S. invest in biofuels like algae.

Gingrich suggested two contrasting slogans last Friday: "You have Newt: Drill here, Drill Now, Pay Less," vs. "You have Obama: Have Algae, Pay More, Be Weird."

"And maybe what we ought to do at Newt.org is we ought to get t-shirts that say 'You choose,'" he said.

At the California Republican Convention, Gingrich spent nearly an hour, in his words, "taking apart Obama's energy speech, point by point," and also introduced a new gas logo and signs in an effort to make cheap gas prices his campaign brand.

At stops in Georgia, Gingrich has promised $2.50 gas, even asking for $2.50 donations online. He urged people to go online and "give a Newt-gallon." At several events in Atlanta, the Gingrich campaign used gas cans to solicit donations.

Gingrich said at his last event Thursday night in Macon that he would take apart the president's speech yet again. Gingrich told crowds earlier in the day that he wanted Chu to go back to being a scientist as "rapidly as possible."

"In fact, I suspect the American people would chip in to buy the airplane ticket later on today," Gingrich said.