It seems not a day goes by without White House contenders John McCain and Barack Obama talking about their support for alternative forms of energy. That includes today, with Obama mentioning energy independence at a town hall meeting in Powder Springs, Ga., and McCain telling the League of United Latin American Citizens (LULAC) convention in Washington, D.C., about ways to wean the U.S. from foreign oil.
The subject is now ammunition in their air war. Over the past weekend, the Republican National Committee aired an ad in Michigan, Ohio, Pennsylvania, and Wisconsin claiming that McCain, R-Ariz., was ready to tackle record gas prices with a "balanced" plan.
The ad then asks what Obama has done for conservation: "But Barack Obama? For conservation, but he just says no to lower gas taxes, no to nuclear, no to more production. No new solutions."
On Tuesday, the Obama campaign debuted an ad suggesting his Republican rival was partly to blame for the high price of gas and would continue to pursue the policies of the Bush administration.
"McCain and Bush support a drilling plan that won't produce a drop of oil for seven years," argues the ad.
The ad also claims that Obama will "make energy independence an urgent priority."
It continues by laying out key elements of Obama's alternative energy solutions, including raising mileage standards, fast-tracking technology for alternative fuels, and implementing a tax cut.
The candidates' biggest disagreements on the issue of energy deal with McCain's support for offshore drilling in the U.S., which Obama opposes. On alternative energy, their biggest disagreement deals with McCain's support for more nuclear power plants.
On the subject of renewable energies, such as solar and wind technologies, the major difference between Obama and McCain is how to get there.
Obama favors government investment, and he would spend billions in tax dollars to develop the technology for zero-emission electric cars.
McCain favors free market incentives and would reward an entrepreneur with a $300 million incentive for advancing the technology for electric car batteries.
During his address to the LULAC on Tuesday, McCain assured the crowd that he would develop more clean energy, and reinforced his stance on nuclear power.
One thing the candidates do agree on is the need for advances in clean coal technology.
"Our coal reserves are larger than Saudi Arabia's supply of oil," McCain said.
According to experts, the actual use of clean coal will take far more of a government investment than the $2 billion a year McCain has proposed.
"It's very costly, so it does require a lot of government support to get it up and running," said Divya Reddy of the Eurasia Group.
When it comes to biofuels, such as ethanol, Obama is more bullish than McCain, wanting to spend billions on the investment in advance.
During an event in May, Obama pledged to set a goal to produce the first 2 billion gallons of advanced biofuels by 2013.
"The technology is just not there right now to make it commercial on the scale that everyone is envisioning," Reddy said. "It seems Obama's goal is fueled by hope and not science."
ABC News' Avery Miller and Sunlen Miller contributed to this report.