20 Terms That Will Make You a Solar Energy Production Master
Annual Production – Amount of total kWh produced in a single calendar year.
Azimuth or Orientation – Azimuth is the direction the roof plane faces, measured in degrees. Orientation is the cardinal direction of the roof plane – north, east, west, or south.
Capacity Factor – The ratio of actual energy generated by a power plant over a time period (usually a year) and the total energy that power plant could have generated over the same time period.
CEC-AC Rating – Rating system used to qualify for the California Solar Initiative; the rating system multiplies the PTC-DC rating of a solar panel by the number of panels and the inefficiency from the DC to AC inverter.
DC to AC Size Ratio – The ratio of the inverter’s maximum AC wattage output to the size of the solar array, measured in DC watts; the closer the ratio is 1:1, the more efficient the system functions.
Design Factor – The ratio of the proposed and optimal system summer output.
Light-Induced Degradation – Refers to the reduction in efficiency of PV cells over time due to exposure to UV light.
Mismatch – The production losses resulting from the interconnection of PV modules that do not have identical properties or experience different conditions from one another (shading, multiple arrays).
Monthly Production – Amount of kWh produced in one month; varies seasonally with monthly production higher in the summer than during the winter (in the northern hemisphere).
Pitch – Pitch is the numerical measure of the steepness of a roof.
Production Simulation – The estimated energy production for the first year based off of computer modeling software.
PV Watts – A calculator, created by the National Renewable Energy Laboratory, that estimates the production and cost of energy of a grid tied photovoltaic system.
Reverse Bias – Situation when a PV cell’s capability to produce power is greatly diminished compared to other PV cells in the same string; this occurs during inadequate conditions, such as a damaged cell or shading.
Shading – When an obstruction, such as a tree or a chimney, blocks sunlight to a panel, limiting energy production.
Short-Circuit Current – The current through the solar cell when the voltage across the solar cell is zero.
Soiling – Accumulation of dust and other particulate matter on a solar panel that negatively affects energy production.
System Loss – The combination of factors, due to real life conditions, that reduce the performance of a PV system from it’s STC rating (Standard Testing Conditions).
System Production – Estimated amount of energy that a solar system will create during the lifetime of the system.
Tilt – Also know as the angle, tilt is the numerical degree of the panel in relation to the horizon (180°).