The skyrocketing price of oil isn't just a burden for American drivers at the gas pump -- it's also a potentially crippling problem for the US military, the nation's number one energy consumer.

The combined branches of the American military burn through a whopping 340,000 barrels of oil a day, reports CNN Pentagon correspondent Barbara Starr. "If you think it's expensive to fill your gas tank," Starr told Situation Room host Wolf Blitzer, "just consider what the military is going through right now."

With the already high price of oil still on the rise, military expenditures on energy are increasing dramatically.

"And with oil near $100 a barrel," Starr reports, "the Pentagon estimates each $10 a barrel increases in oil costs the military -- and the tax payer -- an additional $1.3 billion a year. To pay the tab, money is sometimes borrowed from other vital military programs. "

"If they were a country, they'd be the 38th largest consumer of oil," Lawrence Korb, of the Center for American Progress, told CNN. "If you look at in total, you're getting close to $20 billion a year that the Pentagon has to spend on oil."

The military's single biggest user of oil is the Air Force, whose oil-hungry ships and planes account for $8 billion a year in fuel. That figure represents more than half of the Pentagon's total energy bill.

To mitigate at least a portion of the expense, the military is taking some steps to go "green," CNN reports.

In September, the Air Force will debut a bomber that eschews oil power in favor of a coal-based fuel system. And at the Naval Air Weapons Station, in China Lake, Calif., the Navy is operating a geothermal-powered generating station. One military location, Nevada's Nellis Air Force Base, even has December plans to draw a third of its power from solar energy.

"But with rising oil prices, energy savings are eaten up," Starr continued. "In 2005, the military used 14 million barrels of oil less that what it used two years earlier -- but paid $3 billion more for it."

A May study ordered by the Pentagon found that oil costs threatened to seriously hamper US military capabilities, making it's commitments around the world "unsustainable in the long term."