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
Galois module of "v" to "L", let "I" denote its inertia group. A Galois module ρ : "G" → Aut("V") is said to be unramified if ρ("I") = {1}. In classical algebraic number theory, let "L" be a Galois extension of a field "K", and let "G" be the corresponding Galois group. Then the ring "O" of algebraic integers of "L" can be considered as an "O"["G"]-module, and one can ask what its structure is. This is an arithmetic question, in that by the normal basis theorem one knows that "L" is a free "K"["G"]-module of rank 1. If the same is