Equation 7 · Part 2 · Power Density and What It Permits
subscript
subscript
What this part means
The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.
Its job in the formula
A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.
Full expression→subscript→Article meaning
The passage around this formula
The first factor, capacity density , is a siting and engineering question; the second is a resource and dispatch question. Miller and Keith’s US measurements make the separation visible: they report 2016 mean capacity factors of 32.9 per cent for wind and 22.1 per cent for solar, with 90th-percentile values of 43 and 27.5 per cent, alongside power densities that are not in the same ratio at all [ 4 ] . A technology can improve its capacity factor for years without moving its power density, and the reverse. Van Zalk and Behrens found solar the only one of nine energy types with a statistically significant trend in power density over time, rising an estimated 0.42 watts per square metre…
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
Sources cited in the surrounding passage
- [4] Observation-based solar and wind power capacity factors and power densities ↗
- [3] The spatial extent of renewable and non-renewable power generation: A review and meta-analysis of power densities and their application in the U.S. ↗
These citations provide research context; check each source for the exact claim it supports.