What are photovoltaics?

What is photovoltaic technology?

Photovoltaics is a technology that directly converts sunlight into usable electrical energy. It lets you generate electricity from a renewable source: the sun. Unlike traditional methods of electricity generation, which often rely on fossil fuels, photovoltaics create electricity without causing pollution or using up limited resources.

Photovoltaic systems are used in many different ways. They can be installed on rooftops, where they capture sunlight and convert it into electricity for domestic or business needs. They can also be set up in large solar power plants, where they generate electricity on a larger scale, contributing to the overall energy supply.

How does PV technology work?

PV technology is based on the principle of the photovoltaic effect, which involves the conversion of light energy into electrical energy.

The photovoltaic effect

At the heart of PV technology lies the solar cell. Solar cells are constructed using semiconducting materials, typically silicon, that transform sunlight directly into electricity.

The photovoltaic effect starts when sunlight reaches the surface of a semiconductor. It releases its energy in the form of small particles called photons, which are absorbed by the semiconductor. Electrons within the semiconductor gain enough energy to break free from their atomic bonds, resulting in the creation of electron-hole pairs.

Inside a solar cell, the semiconductor material has a structure that works like a tiny power plant. When sunlight hits the cell, it creates a separation between negatively charged electrons and positively charged holes within the material. This separation sets up an electric field.

To collect the electrons and make them useful, metal contacts are placed on the surface of the semiconductor. These contacts gather the electrons and create a flow of electric current, which is used to create power.

» MORE: How do solar panels work?

How the devices in a photovoltaic system work

Solar panels are made up of multiple interconnected solar cells. When sunlight strikes the panels, the semiconducting material inside the cells absorbs the photons and generates an electric current. The panels are typically installed on rooftops or in open spaces to capture maximum sunlight.

Solar cells are made up of semiconducting materials that absorb photons from the sun to produce an electric current.

The electric current produced by the solar panels is in the form of direct current (DC) energy. Because most homes and businesses use alternating current (AC) for their electrical devices, the inverter converts the DC electricity from the panels into AC electricity, making it compatible with standard electrical appliances and the power grid.

» LEARN: Solar inverters: types, benefits and cost

In some PV systems, batteries are used for energy storage. Excess electricity generated by the solar panels during the day can be stored in batteries for use when the sun isn’t shining at night or during cloudy periods. These batteries store the energy as DC power and can provide backup electricity when needed, reducing dependence on the grid.

» COMPARE: Best solar batteries

You can also use a metering system to monitor the energy production and consumption of a PV system. It tracks how much electricity the system generates from the solar panels and how much is consumed by the electrical devices in the building. This information helps to understand your energy usage, assess the performance of the PV system and potentially feed surplus electricity back into the grid for credit or compensation.

Efficiency and performance

The efficiency of PV technology is measured by how effectively solar cells convert sunlight into electricity. Factors influencing performance include the quality of materials, design of the solar cell and external conditions such as sunlight intensity and temperature.

» COMPARE: Most efficient solar panels

Other types of photovoltaics

Photovoltaic technology comes in a few different forms, including silicon-based, thin-film, concentrated, multijunction and organic/dye-sensitized solar cells.

• Silicon-based photovoltaics: Traditional silicon-based photovoltaics are the most commonly used type of solar technology. They offer high efficiency and durability, making them suitable for various residential and commercial rooftop installations as well as large-scale solar farms.
• Thin-film photovoltaics: Thin-film photovoltaics use a thin semiconductor layer to convert sunlight into electricity. This type of technology is flexible and lightweight, allowing for versatile applications such as integration into building materials, portable solar panels and even wearable electronics.
• Concentrated photovoltaics (CPV): Concentrated photovoltaics employ lenses or mirrors to concentrate sunlight onto small, high-efficiency solar cells. CPV systems are particularly useful in areas with high direct sunlight, such as desert regions. They’re commonly used in utility-scale solar power plants and can achieve very high energy conversion efficiencies.
• Multijunction photovoltaics: Multijunction photovoltaics use multiple layers of semiconductors to capture a broader spectrum of sunlight and increase overall efficiency. These solar cells are commonly used in space applications, such as satellites, where high efficiency and compactness are crucial.
• Organic and dye-sensitized solar cells: Organic photovoltaics (OPV) and dye-sensitized solar cells (DSSC) are emerging technologies. OPV utilizes organic materials and can be produced using low-cost printing, making them suitable for flexible applications. DSSC uses dyes to absorb sunlight and is often employed in consumer electronics and building-integrated photovoltaics.

Cost of solar photovoltaics

Solar photovoltaic (PV) systems can offer significant long-term cost savings and a range of other benefits. However, before making a purchase, it’s crucial to thoroughly evaluate the financial aspects involved.

• Components: To get your PV system up and running, you'll need to invest in solar panels, inverters, mounting structures and the labor to install them. The upfront costs can vary based on the size of your system, the technology you choose, and how complex the installation is.
• Maintenance and operation: Maintaining and operating your PV system isn’t very expensive. It’s generally low-maintenance, mostly requiring occasional cleaning and inspections. Operation costs involve performance monitoring and addressing any minor issues that pop up.
• Technology and efficiency: Different PV technologies and higher-efficiency modules vary in cost.
• Installation complexity: Factors like roof type, accessibility and electrical system upgrades can affect installation costs.
• Local market and labor rates: Regional variations in material costs and labor rates can impact overall system costs.

» MORE: How much do solar panels cost?

Incentives, grants and subsidies for solar energy adoption

To encourage solar energy adoption, governments, utilities and organizations offer various incentives. These include tax credits, rebates, grants and net metering programs, which can help offset initial investment costs and accelerate the return on your investment.

» MORE: How does the federal solar tax credit work?

Don't stress about paying for everything upfront. There are different financing options to consider, like buying with cash, getting a loan, leasing or opting for a power purchase agreement (PPA). Plus, don't forget about the incentives and tax credits offered by the government — they knock down the overall cost and make solar more accessible.

» LEARN: How do solar loans work?

With net metering, when a solar energy system produces more energy than is consumed, the surplus is fed back into the grid and, in return, the energy provider credits the owner's account. This enables solar system owners to offset their electricity bills and even receive compensation for the energy they contribute to the grid.

Economic benefits of solar photovoltaics

Investing in solar PV systems can provide several economic benefits, including the following:

• Energy savings: Using solar energy reduces reliance on grid electricity, resulting in lower utility bills and long-term energy savings.
• Return on Investment (ROI): The time it takes to recover the initial investment in a solar PV system, known as the payback period, depends on various factors, including system cost, energy consumption and available incentives. According to the National Renewable Energy Laboratory, rooftop solar panels typically pay back their energy production within one to four years and can last for about 30 years.  Afterward, the solar PV system generates free electricity, contributing to even greater savings.
• Increased property value: Installing a PV system can increase the value of your property. Potential buyers are often attracted to homes equipped with solar technology due to the long-term savings they offer and their positive environmental impact.

» MORE: Do solar panels increase home value