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
Topological module Topological module In mathematics, a topological module is a module over a topological ring such that scalar multiplication and addition are continuous. A topological vector space is a topological module over a topological field. An abelian topological group can be considered as a topological module over Z, where Z is the ring of integers with the discrete topology. A topological ring is a topological module over each of its subrings. A more complicated example is the "I"-adic topology on a ring and its modules. Let "I" be an ideal of a ring "R". The sets of the form , for