With little fanfare, an off-Island development company has filed plans to build an underwater tidal energy farm in Vineyard Sound. Representatives of Massachusetts Tidal Energy Company (MATidal), based in Washington, D.C., say their installation could potentially supply power to thousands of New England homes. MATidal submitted a preliminary permit application on April 12 to the Federal Energy Regulatory Commission (FERC). If approved, the proposal calls for the installation of one or more clusters of underwater turbines, referred to in the application as "tidal in-stream energy conversion devices." The device is much like an aboveground wind turbine, but submerged to harvest...