While the US is now a net exporter of oil, it is still reliant on imported heavy crude because of refinery constraints

Bloomberg/MSN:

America turned into a net oil exporter last week, breaking almost 75 years of continued dependence on foreign oil and marking a pivotal -- even if likely brief -- moment toward what U.S. President Donald Trump has branded as "energy independence."

The shift to net exports is the dramatic result of an unprecedented boom in American oil production, with thousands of wells pumping from the Permian region of Texas and New Mexico to the Bakken in North Dakota to the Marcellus in Pennsylvania.

While the country has been heading in that direction for years, this week’s dramatic shift came as data showed a sharp drop in imports and a jump in exports to a record high. Given the volatility in weekly data, the U.S. will likely remain a small net importer most of the time.

“We are becoming the dominant energy power in the world,” said Michael Lynch, president of Strategic Energy & Economic Research. “But, because the change is gradual over time, I don’t think it’s going to cause a huge revolution, but you do have to think that OPEC is going to have to take that into account when they think about cutting.”

The shale revolution has transformed oil wildcatters into billionaires and the U.S. into the world’s largest petroleum producer, surpassing Russia and Saudi Arabia. The power of OPEC has been diminished, undercutting one of the major geopolitical forces of the last half century.
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The EIA said the U.S. has been a net oil importer in weekly data going back to 1991 and monthly data starting in 1973. Oil historians that have compiled even older annual data using statistics from the American Petroleum Institute said the country has been a net oil importer since the mid-1940s, when Harry Truman was in the White House.

On paper, the shift to net oil exports means that the U.S. is today energy independent, achieving a rhetorical aspiration for generations of American politicians, from Jimmy Carter to George W. Bush. Yet, it’s a paper tiger achievement: In reality, the U.S. remains exposed to global energy prices, still affected by the old geopolitics of the Middle East.
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To be truly energy independent will require significant changes to refineries which were built before the US started producing large quantities of light crude.  Most of the refining capacity requires heavy crude although it can be somewhat diluted with the light crude most refineries can't handle 100 percent light crude.  They are further hampered by the biofuels mandate that requires them to buy ethanol or other biofuels whether they need it or not.  This waste a lot of money that could be used for the conversion of equipment to handle light crude.  While the biofuels mandate was supposed to reduce reliance on imported oil it is having the opposite effect today.

Strategically, the US would be wise to drop the biofuels mandate and encourage the refineries to change their equipment to handle light crude.  Until it does that it will still be vulnerable to disruptions in the supply of heavy crude.

BTW, when the infrastructure is in place to get more of the Crude from the Permian base to market the US will be a position to export even more oil.  That should happen in the next dozen or so months.