Sandia National Laboratories’ (SNL) environmental assessment modeling tool helps optimize the design of MHK-turbine array layouts within ocean, tidal, and river systems to balance energy generation efficiency with environmental considerations. The new tool, SNL-EFDC, is an augmented version of US EPA’s Environmental Fluid Dynamics Code (EFDC) and includes; (1) a new module that simulates energy conversion (momentum withdrawal) by MHK turbine-like devices including commensurate changes...