The United States has been burning more natural gas this year and relying less on imported energy overall, according to the U.S. Energy Information Administration (EIA), which credited the Bakken, Marcellus and Eagle Ford shales as well as the Permian Basin for increased liquids production.

U.S. net imports of energy as a share of consumption fell to their lowest level in 29 years for the first six months this year, EIA said in a report Friday. “Total energy consumption in the first six months of 2014 was 3% above consumption during the first six months of 2013, but consumption growth was outpaced by increases in total energy production,” the agency said. “These changes led to a 17% reduction in net imports compared with the first six months of 2013.”

The infamous polar vortex of early this year made its presence felt in EIA’s consumption data. Energy use increased every month this year compared with the year-ago period, but January and February accounted for 81% of the total consumption increase due to much colder weather.

Natural gas accounted for 55% of the year-to-date increase in energy consumption, according to EIA. Coal accounted for 24%. Renewable energy made up 12% of the increase, while petroleum accounted for 8% and nuclear electric power accounted for 3%.

“Of the total natural gas consumption increase, the residential and commercial sectors accounted for 69% of the gain, again reflecting the cold winter, while 30% of the increase came from the industrial sector, continuing a long-term trend toward higher industrial use of natural gas,” EIA said.

The growth in domestic energy production came almost entirely from petroleum and natural gas. Petroleum accounted for 52% of the year-to-date increase, while natural gas accounted for 27%. Renewable energy stepped in to account for 9% of the increase, and nuclear electric power accounted for 2%. However, overall coal production fell 1% during the first six months of the year.

“The increased liquids production reflects the use of advanced drilling methods, including hydraulic fracturing and horizontal drilling,” EIA said, noting the Bakken, Marcellus, Eagle Ford and Permian.

“Total energy imports in the first six months of 2014 fell 6% compared with the first six months of 2013, almost entirely because of decreasing petroleum and natural gas imports, which fell 6% and 5%, respectively,” EIA said. “Total energy exports increased 8% compared with the first six months of 2013. The increase was almost entirely the result of a 21% increase in petroleum product exports.”