The state that brought us acid rain figures prominently in the battle for going green this year. Incumbent Sen. John Sununu, the Republican, is “too close to big oil” and “no friend of the environment,” according to environmental groups. His challenger, former Gov. Jeanne Shaheen, cites her solid record as governor as evidence of her support of green causes. Most polls show this race tilting toward Shaheen, although many are within the margin of error.