Solar panels are a collection of solar cells connected together in series, typically 60 for a standard rigid panel and 72 for a high performance rigid panel. Each solar cell produces a small voltage. The series connection adds the voltage together to produce the panel voltage rating.
Most solar panels come with 25 year warranty. Solar panels will slowly degrade, or lose efficiency over time. Typically this is about half a percent per year, so that in year 20, a solar panel will still be operating at 90% of the efficiency it had in year one.
Most solar panels come with two parts to the warranty, an efficiency warranty and a physical defect warranty. A typical efficiency warranty will guarantee no more than 20% reduction in efficiency over the course of the warranty, which is usually 25 years.
The physical defect warranty can range from 10 to 25 years and covers physical issues such as:
Delamination Vacuum pressure is used to laminate Solar panels. Moisture ingress can cause internal corrosion.
Micro-cracks Micro-cracks are pretty much what you’d imagine. They’re tiny cracks on the panel, often hard to see or invisible to the naked eye. Common causes of micro-cracks are manufacturing production, the change in seasonal conditions and poor handling during shipping.
Hotspots More common in warmer climates, hotspots occur when the panel gets to hot. Accumulation of dirt or poorly soldered connections can create hotspots.
Twenty five years is quite a long time, yet solar panels can continue to produce the bulk of their year one efficiency well beyond the warranty period. With no moving parts they are low maintenance and should continue to produce energy for you for many years after the warranty has expired.
The Smart Export Guarantee (SEG) replaces the Feed-in-Tariff (FIT) which closed in 2019. It is a government backed scheme that compensates energy generators for the excess energy they produce (eg from solar, wind etc) that is exported to the national grid if they meet certain conditions.
A solar cell is made from layers of silicon. Silicon is an excellent semi-conductor with 4 balanced electrons. A semi-conductor will only permit the movement of energy (electrons) in certain conditions (when light energy is absorbed).
The top layer of silicon is mixed with a small amount of an element such as phosphorus. Phosphorus has 5 electrons. This mix creates an excess of electrons that are free to move and makes the silicon mix more conductive. The bottom layer of silicon is mixed with an element such as boron, with 3 electrons. The top layer has an effective negative charge.
When light energy, or photons, are absorbed by the silicon mix, they agitate the free electrons in the negatively charged layer, which are then free to travel to the electron holes create by the effective positive charge of the silicon layer mixed with boron.
This movement of electrons creates and electric field, or voltage. The top of the cell is imprinted with a metal grid, such as silver, whilst the bottom layer is imprinted with a metal plate, such as aluminium. These two metals act as electrodes, creating a flow of electrons, which we know as voltage.