A famous doge of the Venetian republic delivered a list of his achievements on his deathbed. In democracies, candidates offer promises for the future, without liability when they fail.
In Tampa, the candidate promised to make America independent of energy imports by the year 2020. This could be achieved by less energy consumption or more domestic production or a combination of both. It would mean no oil imports from Alberta. The Canadian oil industry, partly owned by Chinese partners already, can send the oil to China. It would mean that the additional oil, extracted by fracking, must be cheaper than oil imports from Saudi Arabia or Mexico. But if it was cheaper, it would be exported to the higher-priced world markets and U.S. citizens have to pay the global price anyway. The Republicans are strong believers in the WTO, World Trade Organization.
So they would not go for export customs (like China in rare earths) to keep energy prices for the people lower than the global market would pay for.
When gasoline prices are higher on the East Coast than in Europe, shiploads of gasoline swim from Rotterdam over the pond. They do arbitrage in wet oil, as was done by the banks and speculators in paper oil. Romney forgot to mention that there is no U.S. market for energy. It's a global market. Meanwhile, LNG-tankers take already the route to Europe with Liquefied Natural Gas, because they buy it cheaper here then sell it elsewhere.
Romney is not dull. He knows all that stuff. So why does he offer vague promises, which suggest that energy would become cheaper? Because elections are won with half-truths. Half the truth is worse than a plain lie.