> only when grid is powered, solar systems export power to the grid? Worse yet. When grid is down, some grid-tied systems will not allow any local power use ei

> only when grid is powered, solar systems export power to the grid? Worse yet. When grid is down, some grid-tied systems will not allow any local power use either. Few years back, nearly all grid-tied inverters had this problem. Now situation is slowly improving, with "grid-interactive" systems which do allow local use of solar power with no grid.