A PV installation comprising: a support surface; an array (212, 392) of PV modules, mounted to the support surface, comprising first and second rows of PV modules, each of said PV modules having a lower, south edge and an upper, north edge; the upper, north edges of the first row of PV modules positioned opposite the lower, south edges of the second row of PV modules respectively; PV module support assemblies secured to the upper, north edges of the first row of PV modules and to the lower, south edges of the second row of PV modules respectively so that the upper, north edges are positioned farther from the support surface than the lower, south edges; wind deflectors secured to at least one PV module support assembly opposite the upper, north edges of PV modules in the first and second rows of PV modules; and the PV module support assemblies being constructed to prevent horizontal separation of the PV assemblies of the first and second rows from one another wherein at least some of the PV module support assemblies comprise: a base; and a module support (340, 316), extending from the base, comprising: a support surface supporting the module; a module registration member engaging the PV module to properly position the PV module on the module support; and a mounting element securing the PV module to at least one of the base and the module support (340, 316), characterized by permitting the PV module support assemblies to flex relative to one another so to permit the array of PV modules to follow a contour of a support surface and in that the module registration member is extending from the support surface of a support arm and has laterally extending tabs that create L-shaped surfaces which engage the outside of the PV modules at the north east and north west corners (318, 320), a support surface; an array (212, 392) of PV modules, mounted to the support surface, comprising first and second rows of PV modules, each of said PV modules having a lower, south edge and an upper, north edge; the upper, north edges of the first row of PV modules positioned opposite the lower, south edges of the second row of PV modules respectively; PV module support assemblies secured to the upper, north edges of the first row of PV modules and to the lower, south edges of the second row of PV modules respectively so that the upper, north edges are positioned farther from the support surface than the lower, south edges; wind deflectors secured to at least one PV module support assembly opposite the upper, north edges of PV modules in the first and second rows of PV modules; and the PV module support assemblies being constructed to prevent horizontal separation of the PV assemblies of the first and second rows from one another wherein at least some of the PV module support assemblies comprise: a base; and a module support (340, 316), extending from the base, comprising: a support surface supporting the module; a module registration member engaging the PV module to properly position the PV module on the module support; and a base; and a module support (340, 316), extending from the base, comprising: a support surface supporting the module; a module registration member engaging the PV module to properly position the PV module on the module support; and a support surface supporting the module; a module registration member engaging the PV module to properly position the PV module on the module support; and a mounting element securing the PV module to at least one of the base and the module support (340, 316), characterized by permitting the PV module support assemblies to flex relative to one another so to permit the array of PV modules to follow a contour of a support surface and in that the module registration member is extending from the support surface of a support arm and has laterally extending tabs that create L-shaped surfaces which engage the outside of the PV modules at the north east and north west corners (318, 320),