Sometime last month, National Grid began laying a little over 6,000 feet of new pipe under Bushwick and East Williamsburg in a project that the business — the sole natural gas supplier for much of Brooklyn, Queens, Staten Island and Long Island — says is the latest phase of its Metropolitan Natural Gas Reliability Project, a venture it ties to the needs of “the area’s economic growth.” Residents can expect to see streets suddenly torn up, blocked off by tape, and then covered up as if nothing has changed at all.