How Does Solar Power Create Electricity?

Solar power generates electricity by using either solar thermal systems that convert sunlight into heat to produce steam that drives a generator, or photovoltaic systems, which transform sunlight into electricity through the photovoltaic effect. These two methods are revolutionizing how we harness energy for residential use and offer a sustainable alternative to traditional fossil fuels.

Harnessing solar power is something humankind has been doing for centuries. From the ancient sundials that helped people keep track of time to today’s modern photovoltaic technologies, we have always sought to utilize the sun’s immense potential. Solar energy is a renewable energy resource that is more affordable now than ever before and is used to produce electricity for a wide variety of residential and commercial uses. Electricity produced from sunlight will be a key part of our journey toward sustainable energy in the future.

Today, solar energy is more accessible than ever. According to the International Energy Agency (IEA), solar photovoltaic capacity has grown by 22% annually over the last decade, and costs for solar installations have dropped by 85% since 2010.

Using solar power to generate electricity at home is a very appealing option for a number of reasons: not only would you be reducing your overall environmental footprint and greenhouse gas emissions, but you would be reducing your bills and could even generate some income by selling back excess energy into the grid.

It is therefore a no-brainer that in the European Union a target has been set to encourage EU countries to roll out renewable sources of energy such as solar power to achieve the overarching target of at least 32 percent by 2030. This shift reflects a global push for cleaner energy solutions as we transition toward a renewable energy revolution.

How Solar Energy Produces Electricity?

Human ingenuity has developed two different ways how to harvest the energy of the sun and turn it into electricity:

Solar thermal systems and solar photovoltaic systems

A solar thermal system generates electricity indirectly by capturing the heat of the sun to produce steam, which runs a turbine that produces electricity.

A solar photovoltaic system produces electricity directly from the sun’s light through a series of physical and chemical reactions known as the photovoltaic effect.

Let’s examine each of these systems in more detail.

How Does Solar Thermal Generate Electricity?

You might be familiar with solar thermal technology from a widely publicized series of photos that debuted in the press in 2013, featuring the Ivanpah Solar Power Facility in the Mojave Desert, California.

At the time, it was the largest solar power plant in the world. The array of 170,000 heliostats, which look like large mirrors are tracking the sun’s movement across the sky to power over 140,000 households [1].

The Role of Mirrors and Heat-Transfer Fluid

Mirrors are one of the main components of the solar thermal system. They reflect sunlight onto a receiver containing a heat-transfer fluid, which is warmed up by the sun. The fluid used for this purpose is often molten salt, which is a mixture of 60 percent sodium nitrate and 40 percent potassium nitrate.

Molten salt has a great capacity to store and transfer heat [2]. This allows the storage of the heat generated from the sun for periods of time with no sunlight.

Heat Storage for Nighttime and Cloudy Days

One of the major advantages of solar thermal systems is their ability to store energy for later use. For example, Gemasolar power plant in Spain can store enough heat to produce electricity for an extra 15 hours with no solar input [3].

This unique capability provides continuous power generation even during periods of no sunlight, a key benefit over some other renewable energy systems.

How Does Solar Thermal Compare to Traditional Power Plants?

Once the heat is stored, the rest of the electricity generation process is much the same as it is at coal-fueled power plants. The heat transferred by molten salt creates steam that runs steam turbines, which power a generator to produce electricity.

This method combines the reliability of traditional energy systems with the sustainability of renewable energy.

How Do Photovoltaic Solar Panels Generate Electricity?

The energy of collected sunlight is transformed directly into electricity thanks to the photovoltaic effect. In short, this effect takes place when photons (tiny electromagnetic particles of light) are absorbed by a specific material, which in turn releases electrons from atoms. These released electrons are then available to do the electrical work, such as powering a light bulb.

Although we cannot see the photovoltaic effect with our own eyes, we can look more closely at the solar panels, where this fascinating process takes place.

Solar panels have become a familiar sight to many of us. While the classic, black and dark blue panels are the most common, scientists have also been working on innovative alternatives, such as aesthetically pleasing green-colored panels or even cyanobacteria-powered bio-panels. Regardless of their appearance, all solar panels serve the same purpose: capturing the energy of light.

Each solar panel consists of many smaller units called photovoltaic cells, where the photovoltaic effect occurs. On average, one cell produces around 0.5 volts, and multiple cells are wired together in series to increase their output. For instance, a solar panel with 36 interconnected cells can generate around 18 volts.

How Photovoltaic Cells Work?

Photovoltaic cells are made of a semiconducting material, such as silicon, placed between two conducting layers to create an electric field. To enhance this process:

• Phosphorus is added to one layer to create a negative charge;
• Boron is added to another layer to create a positive charge.

When photons hit the silicon layer, they knock electrons loose from the atoms. The electric field pushes these freed electrons toward metal plates on the sides of the cells, where they are collected as direct current (DC) electricity [4].

Challenges: Efficiency and Orientation

One of the biggest disadvantages of photovoltaic systems is their efficiency rate. At most installations, this rate is between 15% and 18%, meaning over 80% of sunlight that hits the panels is not converted into usable electricity. However, modern panels are continuously improving, with some high-efficiency models now reaching up to 22% or more.

Orientation and placement also significantly affect the performance of solar panels:

• Panels should face south (in the Northern Hemisphere) or north (in the Southern Hemisphere) for maximum exposure.
• Avoid shading during peak sunlight hours, typically from 9 a.m. to 3 p.m.
• Even a small amount of shade, such as from a tree or building, can reduce output by as much as 25%, depending on the system.

Where Does the Electricity Go Next?

Once the solar energy is captured, the direct current (DC) generated by the photovoltaic cells flows into an inverter, which converts it into alternating current (AC). This AC electricity powers our devices and appliances [5].

For any extra electricity not used immediately, there are three main options for homeowners:

• On-grid systems

On-grid systems feed electricity back into the electrical grid. Electricity companies typically give customers credits for any extra electricity that is fed back into the grid from their solar panels. You can use these credits to draw electricity from the grid on days when your solar array doesn’t produce any. One drawback to this type of solar system is that when the grid is down, the system might not be utilized.

• Off-grid systems

Off-grid systems are standalone solar systems that rely on batteries to store solar energy for use during the night and at other times when more electricity is needed than is generated by the solar system.

• On-grid solar systems with a battery backup

On-grid solar systems with a battery backup feed solar energy-generated electricity back into the grid when the grid is operating, but in the event of a grid blackout, these systems will switch to an off-grid mode. In this off-grid mode, the backup battery is used to supply stored solar power, and the solar panels charge the battery [6].

How Can You Generate Solar Electricity at Home?

Solar power is one of the most attractive renewable energy options for homeowners. With costs falling by 85% since 2010, installing solar panels at home is now more affordable than ever. In fact, solar power is becoming the cheapest way to generate electricity, according to Bloomberg New Energy Finance analysts. 

Home solar systems can power appliances, lighting, and more, even on cloudy days, thanks to advanced photovoltaic technology. Solar panels are also relatively compact and can be placed on rooftops, balconies or different places on your property.

So can you generate solar electricity at home? The simple answer is yes, you can. Indeed, there is a term for generating power at home: it is called micro-generation and refers to the stand-alone generation of low carbon heat and/or electricity which is feasible for the average home [8].

How to do it is a fairly straightforward question too: by installing a set of photovoltaics. Having said that, while going off the grid entirely may be difficult for many homeowners, generating a portion of a home’s electrical needs is definitely possible with solar power.

The extent to which solar power generation is an attractive option for your own houseful will be largely determined by the following factors:

• the availability of the key resource – the sun
• space for the solar system size you need to power your household’s energy needs
• the level of cost and investment involved
• the local permits required

These are important considerations you will need to take into account and look into before planning to invest in a solar power system.

One of the biggest disadvantages of photovoltaic systems is the conversion rate of the sunlight into electricity, otherwise referred to as the efficiency. At most installations, this number remains between 15 and 18 percent. This means that over 80 percent of the sunlight falling on the solar panel is not transformed into power.

How Much Energy Do Solar Panels Produce?

In terms of how much energy you will be able to generate, this largely depends on the availability of the sun. Solar photovoltaic panels use the sun’s energy to create electricity to run appliances and lighting.

This doesn’t mean that it needs to be sunny all the time for power to be generated, as the technology relies simply on daylight.

How to Get the Best Energy Output from Your Solar Panels?

Solar cells, which are usually placed on the roof, are made up of layers of semi conducting material which create an electric field, when the sun shines on them, causing electricity to flow. The stronger the sun, the more electricity is produced [8].

But how much power you will generate will also depend on where the solar panels or tiles are placed. Roofs are an option that is preferred by a number of people, but to maximize energy there needs to be no shade on the panels, especially during the prime sunlight hours of 9 a.m. to 3 p.m.

If you are able to install your solar system to face the South this will provided an optimum potential for energy generation. This is very important as even if just one of a solar panel’s 36 cells is shaded, power production will be reduced. With today’s modern technology, solar panels are light and solar tiles, in particular, can replace traditional roof tiles.

Most photovoltaic units installed in homes are linked to the utility grid. This allows for the power collected through the solar powers to be fed directly into the utility power distribution system of the house or building. In this way, the solar energy system installed reduces demand for power from the utility when the solar array is generating electricity – thus lowering the utility bill. These types of solar energy systems are also known as “on grid” or “battery-less” and they make up approximately 98 percent of the solar power systems installed today [9].

Practical Considerations for Homeowners Interested in Going Solar

If you are considering photovoltaic solar panels for your home, here are a few key facts to help you make an informed decision:

1. Cost and ROI: The average cost of installing a solar system in the U.S. is around $20,000, but with federal tax credits and incentives, homeowners can save up to 30% of the installation cost. Most solar systems pay for themselves in 7 to 10 years.
2. Lifespan: Most solar panels come with a 25-year warranty and can continue generating electricity efficiently for 30 years or more.
3. Energy production: A typical 5 kW system can generate about 6,000 to 8,000 kWh annually, enough to offset a significant portion of an average household’s electricity needs.

The Future is Bright with Solar Energy

Solar power is not just a technology of the future—it’s a solution for today. By harnessing the sun’s energy through solar thermal systems or photovoltaic panels, we have the ability to generate clean, sustainable electricity that reduces our environmental footprint and saves money over time.

For homeowners, adopting solar energy is a step toward energy independence and a greener future. Whether you are looking to power your entire home, supplement your energy needs, or reduce your utility bills, the options are more accessible and affordable than ever. With innovations in efficiency, storage solutions, and incentives like tax credits, there has never been a better time to explore solar power.

Ready to take the first step?

1. Assess your home’s solar potential by checking for sufficient sunlight and available installation space.
2. Explore government incentives and rebates in your area.
3. Reach out to a trusted solar provider for a customized quote.

By switching to solar, you are not only investing in your own energy future but also contributing to a cleaner, more sustainable planet for generations to come. Start your solar journey today and be part of the renewable energy revolution.

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