As environment groups across the US get up this morning, nursing hangovers from celebrating the end of the Atlantic pipeline dream from dual proponents Dominion Energy and Duke Energy, there is a feeling in the air that some kind of threshold has been passed. For Dominium it was not enough to simply change its mind on the pipeline, take a hit on its quarterly numbers and draw a line under the whole episode, but it went the whole hog and sold off its natural gas business to Berkshire Hathaway for just under $10 billion, of which some $5.7 billion is assumption of debt. Unfortunately this puts the assets in a pot with almost limitless cash, so there is no saying…