Photovoltaic system in northern climes to 5.61 kWh/m²/day in the sunniest regions. For large systems, the energy gained by using tracking systems can outweigh the added complexity (trackers can increase efficiency by 30% or more). For very large systems, the added maintenance of tracking is a substantial detriment. Tracking is not required for flat panel and low-concentration photovoltaic systems. For high-concentration photovoltaic systems, dual axis tracking is a necessity. Pricing trends affect the balance between adding more stationary solar panels versus having fewer panels that track. When solar panel prices drop, trackers become a less attractive option. Systems designed to deliver alternating
Localization of a module of flatness in algebraic geometry, saying in particular that the inclusion of the open set Spec("S""R") into Spec("R") (see spectrum of a ring) is a flat morphism. In terms of localization of modules, one can define quasi-coherent sheaves and coherent sheaves on locally ringed spaces. In algebraic geometry, the quasi-coherent "O"-modules for schemes "X" are those that are locally modelled on sheaves on Spec("R") of localizations of any "R"-module "M". A coherent "O"-module is such a sheaf, locally modelled on a finitely-presented module over "R". Any textbook on commutative algebra covers this topic, such as: Localization of a module In