A sunny way forward: How solar power works

Date:9 July 2019 Author: Sam Spiller Tags:, , , , , , , , ,

We’ve got a natural nuclear reactor 149 million km away.

Solar energy works by capturing energy from sun and transforming it. Our sun, which is located around 149 million kilometers away from earth emits tiny pockets of energy called photons. These photons travel the distance from the sun to earth in about 8.5 minutes every hour of the day. Each day we’re hit with enough photons to generate solar energy to theoretically satisfy our global energy needs for an entire year.

Photovoltaic (PV) solar panels are made up of multiple solar cells (devices that convert photons from the sun into electricity). Solar cells are made of silicone which in turn act like semiconductors. The solar cells are constructed of a positive and negative layer which create an electric field, much like how a batteries are made.

When photons from the sun come into contact with a PV solar panel they knock electrons loose from their atoms, and if conductors are attached to positive and negative sides of a cell, it creates an electrical circuit. Multiple cells make up a solar panel, and multiple panels can be wired together to form a solar array.

Solar panels generate DC (direct current) electricity. This means electrons flow in one direction around a circuit. Unfortunately, however, a lot of the worlds power consumption uses AC (alternating current) electricity. An advantage AC electricity has over DC electricity is that AC electricity can be rapidly transformed to higher or lower voltage levels, something that is very difficult to do with DC electricity. AC electricity is also much less expensive to transmit over long distances.

How do we convert DC electricity to AC electricity?

Solar inverters play a vital role in any solar energy system and are often regarded as the brains behind the system. The solar inverter converts DC electricity generated by the solar panel into a AC electricity which can then be transmitted to our homes from solar fields hundreds of kilometers away. The inverter takes the DC electricity and, in simplified terms, runs it through a transformer. It is almost as though the inverter is tricking the transformer into thinking it is getting AC electricity by forcing the DC electricity to act in a way similar to AC.

During peak daylight hours, the typical grid-tied PV solar panel system provides more energy than one single household or business needs, so any excess energy is sent back to the solar farm for use elsewhere.

Image: Unsplash

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