What’S The Difference Between Photovoltaic Panels And Solar Panels?

Photovoltaic panels and solar panels refer to the same technology that converts sunlight into electricity. Both terms describe panels composed of solar cells made from materials like silicon that generate electricity when exposed to sunlight.

The key difference between the two terms has to do with their etymology. “Photovoltaic” comes from the Greek word for light, “photo,” and electricity, “voltaic.” So photovoltaic literally means “light-electricity.” Solar panel is a more colloquial term that conveys the solar origins of the technology.

While photovoltaic panel is the more precise and technical term, solar panel is very widely used and understood. This article will explore the similarities and differences between photovoltaic and solar panels in more detail.

Definition of Photovoltaic Panels

Photovoltaic panels, often referred to as PV panels, are devices that convert sunlight into electricity using the photovoltaic effect. They are made up of many small solar cells, each containing a photovoltaic material that absorbs photons from sunlight and releases electrons. These free electrons create an electric current that can be captured and used as electricity.

The most common photovoltaic material used in panels is silicon, though other materials like cadmium telluride and copper indium gallium selenide are also used. When sunlight hits the photovoltaic material, the photons excite electrons in the material to higher energy states. This frees the electrons from their atomic bonds, allowing them to flow through the material and produce electricity.

The solar cells in a photovoltaic panel are connected together to form modules, which are then connected to form arrays. Wires from the arrays carry the direct current (DC) electricity to an inverter, which converts it into alternating current (AC) for everyday use and connection to the electrical grid. This allows the solar energy captured by photovoltaic panels to power homes, buildings, and more.

Some key references on how photovoltaic panels work:

From IonSolar: “Photovoltaic panels are made up of small photovoltaic cells connected together and made out of semiconducting materials like silicon that exhibit the photovoltaic effect.”

From Quora: “PV cells convert sunlight directly into DC electricity using semiconducting materials.”

Definition of Solar Panels

Solar panels, also known as photovoltaic (PV) panels, are devices that convert sunlight into electricity using the photovoltaic effect. The photovoltaic effect refers to photons from sunlight knocking electrons free from atoms, generating an electric current (1). Solar panels are made up of solar cells, which are assembled together into modules and arrays. Solar cells are made of semiconducting materials like silicon that are treated to form an electric field. When sunlight hits the cell, the energy strikes the electrons in the cell, knocking them loose and allowing them to flow freely, creating electricity.

Solar panels can vary greatly in size, from small rooftop arrays on homes to massive solar farms covering acres of land. Their main purpose is to harness the sun’s energy and convert it into usable electricity that can power homes, buildings or electrical grids. Solar power from panels provides a renewable and sustainable energy source as opposed to fossil fuels.

(1) https://www.livescience.com/41995-how-do-solar-panels-work.html

Comparison of Technology

The key technological difference between photovoltaic panels and solar panels is in how they convert solar energy. Photovoltaic panels, commonly known as solar PV panels, use semiconducting materials like silicon to directly convert sunlight into electricity through the photovoltaic effect. Solar panels, also called solar thermal collectors, absorb solar radiation to heat water or another liquid which can then be used to provide hot water and heating. https://www.products.pcc.eu/en/blog/photovoltaic-panels-vs-solar-panels-differences/

Photovoltaic panels consist of many solar cells containing a photosensitive material like silicon. When light hits the solar cells, electrons are knocked loose and flow through the material to produce an electric current. Solar panels instead consist of tubes of water or a heat transfer fluid that are heated as sunlight hits the panel. This thermal energy can then be used directly for heating, or to produce electricity via a heat engine or generator.

So in summary, photovoltaic panels directly generate electricity through the photovoltaic effect while solar panels collect thermal energy that must be converted to electricity through additional mechanisms. The core technologies and materials are fundamentally different between the two types of solar panels.

Efficiency

Photovoltaic panels, also known as PV panels, tend to have lower efficiency rates than solar thermal panels. Most residential PV panels operate at 15-22% efficiency, meaning they convert 15-22% of the solar energy that hits them into usable electricity (1). In contrast, solar thermal panels can achieve 70-80% efficiency in converting sunlight into heat energy (1).

The reason for the difference in efficiency has to do with the inherent physics of the two technologies. PV panels rely on semiconductor materials that have limits in how efficiently they can absorb photons and release electrons. Solar thermal panels, on the other hand, simply heat up a liquid that flows through the panel, which is a simpler process. Additionally, PV panels lose some energy when converting direct current electricity into alternating current for household use (2).

While lower in peak efficiency, PV panels have the benefit of directly generating usable electricity. Solar thermal is limited to heating applications like water and space heating. So PV panels tend to have greater versatility and uses for consumers (3). Both technologies have a role to play, with PV better for distributed electricity generation and solar thermal ideal for residential heating needs.

(1) https://www.skillstg.co.uk/blog/photovoltaic-panels-vs-solar-panels/

(2) https://www.products.pcc.eu/en/blog/photovoltaic-panels-vs-solar-panels-differences/

(3) https://blog.ecoflow.com/us/solar-photovoltaic-vs-solar-thermal/

Cost

The cost of photovoltaic panels is generally higher than the cost of solar thermal panels. According to research from Energysage (Energysage, 2024), photovoltaic panels cost an average of $2.70 per watt, while solar thermal panels average $2.10 per watt. This means a typical 5kW photovoltaic system would cost around $13,500, compared to $10,500 for an equivalently sized solar thermal system.

The main reason for the cost difference is that photovoltaic panels are more technologically advanced, requiring silicon cells and more complex components. Solar thermal panels, on the other hand, are a simpler technology relying on fluid circulation to capture heat. Additionally, photovoltaic systems require more supporting equipment like inverters to convert the electricity generated.

That said, prices for both technologies have dropped significantly in recent years. According to Forbes (Forbes, 2024), average photovoltaic costs have fallen from over $7 per watt in 2010 to around $2.70 today due to improved manufacturing and economies of scale. So while photovoltaic remains more expensive upfront, the gap is narrowing over time.

Applications

Photovoltaic panels and solar thermal panels have some overlapping but also some distinct use cases and applications. Photovoltaic panels are best suited for electricity generation applications like powering homes, businesses, and the grid. Their ability to directly convert sunlight into electricity makes them ideal for these use cases. According to one source, “Photovoltaic panels are primarily used to convert solar radiation into electricity” (Skillstg).

Solar thermal panels, on the other hand, are more often used for water and space heating applications. As one source explains, “Solar thermal collectors are designed to absorb solar radiation and convert it into heat energy that can be used for water heating, space heating, and even cooling” (PCC). So while photovoltaic panels generate electricity, solar thermal panels tend to be used for direct heating applications.

That said, there can be some overlap in applications. For example, photovoltaic panels can be used for solar water pumping and heating in some cases. But their primary purpose remains generating electricity. Understanding the core technological differences helps match each panel type to its optimal uses.

Environmental Impact

Both photovoltaic and solar panels provide clean, renewable energy with minimal environmental impact compared to fossil fuels. However, there are some differences in their environmental pros and cons.

Photovoltaic panels have very low emissions during operation, but manufacturing does require energy and rare materials like silicon, which has some environmental impact (Environmental Impacts of Solar Power, 2013). Thin-film PV like cadmium telluride is of particular concern due to toxicity, though recycling can help mitigate this (Environmental impacts of solar photovoltaic systems, 2021). Overall PV panels have relatively low lifetime carbon emissions.

Solar thermal panels also have minimal emissions when generating electricity. However, some concentrated solar power plants use significant amounts of water for cooling, putting strain on water resources in arid regions. This is less of a concern with photovoltaic panels (Solar energy and the environment, n.d.).

In terms of land use, utility-scale PV and concentrated solar plants can potentially displace wildlife habitat and vegetation. Careful site selection is needed. Rooftop solar minimizes land impact for both technologies (Environmental Impacts of Solar Power, 2013).

Overall, both technologies are far superior environmentally compared to conventional power generation. With responsible manufacturing and deployment, their pros greatly outweigh the cons.

Future Outlook

There are a number of exciting innovations on the horizon to improve both photovoltaic and solar thermal technologies.

For photovoltaics, advanced solar cells such as perovskites and tandem designs offer the potential for higher efficiencies and lower costs. Perovskites can be manufactured using low-cost methods like printing and can achieve efficiencies over 25%. Tandem cells, which combine two different solar cell materials, can achieve efficiencies beyond 30%.

Researchers are also working on improving manufacturing methods, flexibility, and applicability of photovoltaics to create new opportunities for solar energy. Examples include solar window coatings and solar paint.

For solar thermal, innovative concentration and storage designs may improve efficiency and dispatchability. Multi-tower concentrated solar power plants can achieve higher temperatures and incorporation of thermal storage allows solar thermal plants to provide power on demand.

Advanced heat transfer fluids, coatings, and materials may enable new high-temperature concentrating solar thermal designs in the future. For example, researchers are developing solar thermophotovoltaic systems which use solar-heated emitters to generate electricity.

Conclusion

In summary, the key differences between photovoltaic panels and solar panels are:

• Photovoltaic panels directly convert sunlight into electricity using semiconducting materials, whereas solar thermal collectors absorb sunlight to heat a liquid.

• Photovoltaic panels tend to have higher efficiencies, typically 15-20%, compared to solar thermal efficiencies around 15-30%.

• Photovoltaic systems are more complex and expensive to manufacture but require less maintenance than solar thermal systems.

• Solar photovoltaic panels take up less space than solar thermal collectors for an equivalent power output.

When deciding which solar technology is better for your needs, consider factors like climate, space availability, upfront costs vs. long-term savings, and local regulations and incentives. For most residential uses, rooftop photovoltaic systems are preferable for their simplicity, higher efficiency, and flexibility in installation.

Speak to a qualified solar installer to determine whether photovoltaic or solar thermal systems make the most sense for your particular home or business.