The Tennessee Valley Authority is increasing its fuel adjustment charge by 0.7 percent in June. A typical household power bill will rise eighty cents for the same amount of use. TVA spokesman Scott Brooks said the mild winter that was beneficial to customers allowed the federal utility to credit some of the savings to the monthly fuel charge in February, March and April. Those savings have been used up and Brooks said the fuel charge for June is more reflective of TVA's actual costs for producing electricity. TVA said earlier that the mild winter and cheaper natural gas prices lowered its fuel expenses through March by $323 million from the first six months of its previous fiscal year.