s early as the 7th century BCE, humans started their attempts to harness solar energy. The sunshine was used to light fires with the help of magnifying glass materials. A few centuries later, Greeks and Romans developed mirror technology that allowed them to use solar power to light torches for their ceremonies.
The discovery of the photovoltaic effect in the 19th century and the invention of modern-type solar panels in the 1950s opened the door for generating electricity from solar energy. Let’s take a look at how exactly solar panel systems work.
What is solar energy? The nature of solar radiation
Solar energy is created by a process called nuclear fusion. When two light nuclei collide in the sun’s core and fuse to create a single helium atom, radiant energy is released into space. Only a small portion of this energy strikes the Earth, yet this amount is enormous.
Or planet gets two forms of power from the sun: light and heat, which we use to produce electric and thermal energy. In this article, we will focus only on solar energy electricity obtained from sunlight.
Harvesting solar energy: how is power from the sun collected?
Solar panels capture the photons - the particles of solar energy that compose sunlight - and generate electricity from solar power they have collected.
Each solar panel consists of solar cells – small devices that capture sunlight and transform it into solar energy electricity. Yet, not all radiation reaching the panels gets absorbed – most residential panels convert only around 20% of the light they collect into electricity.
How does generating solar electricity work?
Electricity from solar is obtained through the photovoltaic effect - generation of voltage and electric current in a material when it is exposed to sunlight. The solar industry employs semiconductors – materials that collect light most efficiently.
A solar cell is basically a sandwich of two different layers of semiconductor, usually silicon. The top layer of the cell contains excess electrons (negatively charged particles), while the bottom layer contains holes (positively charged particles). When the sun’s rays hit the top layer of a solar panel, they knock the excess electrons loose from their parent atoms. The electrons recombine with the holes in the place of the junction between the top and the bottom layers, creating an electrical current. This current is captured by the wiring of a solar panel and then converted to alternating current by an inverter.
Can a solar panel deliver power on a cloudy day or at night?
As explained above, solar systems generate electricity by collecting the energy of the sun. But do they need direct sunlight? In fact, they don’t. Solar panels can generate electric power even from indirect sunlight, for example, on cloudy days, in partial shade, and when it rains. However, the energy output will be lower since fewer photons get absorbed by your solar modules.
As you can probably guess, solar panels can’t produce electricity at night when there is no sunshine at all. This does not mean, however, that you can use your solar system to power your home only during the day. Solar energy and electricity storage technology, such as solar batteries, allow you to supply your home with electricity all day long.
What types of solar energy installations exist?
Most residential solar energy systems are rooftop installations on stand-alone houses. Domestic solar modules can also be installed on the ground or even integrated into the facades of the building. Commercial and industrial solar energy systems are generally bigger than residential systems, as they need to produce more electric power for large-scale use. Another form of solar is utility-scale projects – large solar power plants selling their electricity to utilities.
Is solar energy electricity a green choice?
Yes, electricity from solar is clean energy that we derive from the sun. Solar modules create no carbon emissions during operation, and the manufacturing process of a solar panel has a much smaller carbon footprint than fossil fuels. Using solar energy has almost no negative impact on the environment.
What countries are leading in solar energy?
China is now the undisputable global leader, with an installed solar capacity of over 300 gigawatts. Additionally, the country is responsible for over three-quarters of the world's PV panel supply chain. The USA takes second place in this ranking. Solar power is expanding rapidly in the United States, especially in its utility and residential sectors. Solar electricity is becoming more affordable; nowadays, more than 3.5 million U.S. households use it for their energy needs.
How to plan your home solar panel system
It is no surprise that solar power is a growing trend among homeowners across the country. It reduces dependence on the electric grid and dramatically lowers electricity bills, while pairing PV modules with a battery gives you an uninterrupted power supply even during blackouts. Still, planning to power your house entirely or partially with solar energy electricity requires considerable financial investments and research. Long story short, estimate your electricity needs, assess your home’s solar potential, and check out available solar incentives. If you have difficulties with any of that, consult your solar installer: they will help you plan and manage the process.