Electricity prices for the first half of the year increased the most in a year-over-year basis since 2009, according to the Energy Department's statistics arm.

U.S. power prices are up 3.2 percent, according to the U.S. Energy Information Administration. Prices rose everywhere except for the Pacific census region, which includes Alaska, California, Hawaii, Oregon and Washington, where they dropped 2.5 percent.

New England led much of the spike, as prices there jumped 11.8 percent. The region faced a brutal winter, leading to a natural gas supply crunch that caused prices to soar.

Many electricity customers there live in competitive power markets — unlike the regulated utility monopolies that dominate much of the country — relying on third-party providers for their power. When the cold came in, wholesale prices skyrocketed 45 percent, which the EIA called "the primary driver of the recent increase in New England retail rates."

Some Southern states fared better than the national average. A region of interior Southeastern states that includes Kentucky, Tennessee, Alabama and Mississippi experienced a 3.1 percent hike. A clutch of states that includes Louisiana, Texas, Oklahoma and Arkansas saw a 2.4 percent increase.

Other power prices increases included: 6.7 percent in the Mid-Atlantic; 4.5 percent in the Mountain region; 4 percent in the South Atlantic, which is bounded by Maryland to the north and Florida in the south; 3.7 percent in part of the Midwest that stretches from Wisconsin to Ohio; and 1.8 percent in a group of states anchored by North Dakota in the northwest and Missouri in the southeast.