Are you wondering how solar panels work? First, the two main types of solar energy technologies include concentrating solar-thermal power and photovoltaics (PV). They absorb sunlight (solar radiation, also known as electromagnetic radiation) and convert it into energy used to generate electricity, which can be used on the spot or stored in either batteries or thermal storage for future use.
Solar panels utilize PV. Here, we will break down how PV works so that you understand the solar panel.
The Breakdown of a PV System
The PV technology in solar panels is what captures the solar radiation and turns it into usable energy. Sunlight activates the PV, therefore activating the solar panel.
A PV device is a small cell that produces about 1-2 watts of power alone. There are many PV cells in a solar panel. They are connected in chains, forming larger units (modules, aka panels).
The PV cells are made of ultra-thin semiconductor materials (usually silicon) sandwiched between protective materials (plastic or glass) to withstand the outdoors. While silicon is the most used material because it is abundant and affordable, there are other possibilities, including quantum dots, perovskite, semi-transparent organic, and even cells enhanced with graphene, hair, or chili.
A module can generate electricity on its own or be connected to other modules, forming arrays. A PV system consists of single or multiple arrays connected to the electrical grid. They can be as large (or small) as necessary, thanks to this modular structure. These panels are rigid, but new advances are creating better flexible solar panels, so eventually, solar energy applications with PV will be truly endless.
Solar panels are just one part of a PV system, which also includes mounting structures (positioned so that the panels face the sun) and components (inverters and wiring) that convert the direct-current (DC) electricity produced by modules into the alternating-current (AC) electricity used to power buildings and infrastructure.
If the solar panels are free-standing (not on a building or canopy), like in an open field, they can be made to move with the sun or reflect the sunlight shining on the floor back up onto the solar panel to increase efficiency. However, the latter only works if the solar panel is double-sided.
How Solar Panels Produce Electrical Current
The thin semiconductor wafer within a PV cell comprises two layers of silicon (95% of the time) – one negatively charged and the other positively charged to form an electric field. When solar radiation strikes a PV cell, it energizes it, causing electrons to ‘loosen’ from atoms within the semiconductor wafer. The wafer’s electric field sets the loose electrons into motion, creating an electrical current that can be extracted for use as power via contact with a conductive metal.
PV Solar Cell Efficiency Explained
The amount of energy produced by the cell compared to the light energy shining on it dictates the PV cell’s efficiency. The closer those two figures are, the more effective the PV cell is at converting energy from solar radiation into electricity. However, many factors are at play here, including the intensity of light available, the wavelengths of light available, temperature, air quality, dirt or other grime on the module, and performance attributes of the cell.
How Electrical Energy Powers a Building
After the solar panel converts the energy into electricity and the inverter converts it from DC to AC electricity, the power runs through an electrical panel and is distributed within a building. Electricity coming from the grid by an electric utility company works the same way.
If the solar panels don’t generate enough electricity, the building’s electrical panel can draw from the grid. On the other hand, suppose the solar panels generate surplus electricity (more than the building needs). In that case, the power can be sent to the grid, and the utility company often provides credits for the contribution. This is called metering.
Solar Energy Storage Solution: Batteries
Batteries are the primary storage solution for solar photovoltaic energy. They save excess electricity for future use. This method enables off-grid living. When the solar panels don’t generate enough electricity to meet demand, a building can draw power from the battery; when the solar panels generate excess, it is stored in the battery instead of being sent to the grid.
Batteries are also playing an increasingly vital role in utilities. Their adoption will modernize and stabilize electric grids, allowing customers to feed solar energy from residential rooftop solar arrays or commercial-scale solar parks back to the grid to be stored in batteries for times of peak demand.
Some fantastic examples of battery storage in the real world include:
- The 33MW battery storage facility near Bristol, UK.
- The massive system in California that’s 3x bigger than the Tesla Powerpack project in South Australia.
- And the Elkhorn Battery Storage Facility, which is also in California and set to be the world’s most enormous.
Not a battery, but another feat in prolonging the use of solar is the Power Potential Project in the UK, a trial of reactive power that shows it is possible to provide electricity from solar power systems to customers at nighttime.
PV Solar Panel Technology Progress
Over the past two decades, PV technology has rapidly improved, yielding improved durability, lower costs, and better efficiency. It will likely progress faster as we transition to a carbon-neutral world. Furthermore, many people are beginning to understand the numerous benefits of installing solar panels on their property.
You will undoubtedly see more and more solar panels on rooftops, along roadsides, over highways, in fields and deserts, and floating on lakes, canals, or the sea over the years to come. Australia is even preparing for the expected surge of solar devices with a solar panel recycling facility. Recovering what those panels contain is another matter: the silver that carries most of a module’s value is the hardest part to get back.
