olar technology is a total revolution in energy production. It is irreversibly changing the global energy landscape, helping fight climate change, and cutting utility costs. Not only businesses but a large number of residential consumers have already made a switch to solar in order to save on electricity bills and take a practical step toward a greener future.
Understanding solar power: solar basics for newbies
If you are new to solar but consider installing your own PV panels, you might want to know what solar energy actually is. As you can imagine, solar power generation technologies can be hard to grasp. We are here to introduce you to the basics of solar and give a fuller picture of converting sunlight to electricity.
What is solar energy?
The sun is a primary source of energy on Earth. But not all energy it emits reaches the surface of our planet: around 30% of solar radiation is reflected back to space, 20% is absorbed by water vapor and the remaining 50% reaches the Earth's surface. Nevertheless, it is still highly abundant: the amount of solar energy striking the Earth in one hour is more than the world consumes in a year.
It is created as a result of a proton-proton fusion at the core of the sun - a nuclear fusion when protons merge together to form a helium atom. A tremendous amount of energy in the form of waves and particles is generated during this process. It drifts away from the sun, flows all through the Solar System, and eventually reaches the surface of the Earth.
The solar radiation spectrum includes waves of different wavelengths and frequencies, such as visible (Vis), ultraviolet (UV), and infrared (IR). Solar panels mostly absorb visible light but also can take advantage of almost half the infrared rays.
How do solar panels convert solar energy into electricity?
A solar panel consists of several separate solar cells that are typically made of silicon. This semiconducting material is used in about 95% of solar panels on the market due to its generation efficiency, abundance, and stability.
Solar power is produced with the help of a phenomenon called photovoltaic effect, which was discovered back in 1839. Once sunlight hits the surface of a solar panel it is absorbed by the thin silicon layer of its PV cells. Photons knock electrons free from atoms inside a cell, and their movement toward its front surface causes an electrical imbalance between the cell's front and back sides creating voltage. This is how electric current appears, which is captured by cables and wires attached to a solar panel.
Is the electricity generated by solar panels ready to power my home?
The electricity generated in a solar cell can’t be used to power your home appliances yet. The thing is, solar panels produce direct current (DC) electricity, which means electrons flow in one direction around a circuit. But most electric home appliances use alternating current (AC) electricity, where the flow of electric charge periodically reverses its direction. AC is more widely used today as it allows electricity transmission over longer distances, has fewer energy losses and is safer to work with.
To convert DC electricity produced by a panel to AC a solar inverter is used – a crucial piece of equipment in a solar array. But its work is not limited to power conversion. Modern inverters can also track and report the electricity output of solar panels as well as ensure safe PV system operation. In solar-plus-battery systems, advanced inverters help operate independently from the grid and ensure backup power during outages.
There are three types of solar inverters: string inverters, microinverters, and power optimizers. The first one is a centralized inverter, which converts energy from multiple solar panels. Microinverters are installed beneath each panel and convert DC to AC electricity right on the rooftop. Power optimizers are also located under each panel. They correct the voltage generated by the panels to maximize their performance but don’t convert electricity onsite. Instead, they send it to a central string inverter.
How is energy output from the solar panels measured?
The energy generated by solar panels can’t be measured with old analog electricity meters. Solar panel owners have to install a smart meter, which automatically sends the readings to their utility company. If a smart meter is already installed, it will need a reconfiguration to be able to measure the amount of power that is being sent from a solar installation to the grid.
What if I consume less energy than my solar system produces?
If your grid-connected solar system generates more electricity than you consume, it will feed excess electricity from solar panels out to the grid. Some regions offer a net metering program, which means your power provider will pay you for any extra electricity you put back.
Another solution to this problem is to store excess energy from solar panels in a battery. It can provide backup power during grid outages and cut utility bills by discharging during hours of peak demand when the cost of electricity goes up.