Is Solar Photovoltaic Cell Renewable Or Nonrenewable?

Table of Contents

Definition of Renewable vs Nonrenewable

Renewable energy sources are naturally replenished and virtually inexhaustible. They include sunlight, wind, water, plants, and geothermal heat. Renewable resources regenerate and can be used again and again. Nonrenewable energy comes from sources that will eventually dwindle in supply. Fossil fuels like coal, oil and natural gas are finite resources that formed underground from the remains of plants and animals over millions of years. Unlike renewable sources, nonrenewables can’t be easily replenished in a short period of time.

The key difference between renewable and nonrenewable energy is renewal rates. Renewable sources can regenerate within a human lifespan, while nonrenewables take many years to form and replenish. Renewables are constantly renewed by natural processes and are considered unlimited. Nonrenewables exist in fixed amounts that are being depleted much faster than new reserves are created. Once these finite resources run out, they are gone for good unless new technological methods are created to reproduce them.

How Solar Cells Work

Solar cells, also known as photovoltaic cells, convert sunlight directly into electricity. They are made of semiconducting materials that exhibit the photovoltaic effect. When sunlight hits the solar cell, photons are absorbed by the semiconducting material, causing electrons to break free from their atoms. This generates electron-hole pairs, which create a flow of electrons or electrical current.

The photovoltaic effect occurs at the atomic level as photons interact with the solar cell material. Silicon is commonly used in solar cells due to its abundance and semiconducting properties. When a photon hits a silicon atom, its energy gets transferred to an electron, exciting it to a higher energy state and allowing it to move freely. Meanwhile, the area where the electron was creates a positive charge or “hole”. The movement of the electrons and holes generates an electric current.

Solar cells contain electric fields formed by the special junctions between two different semiconducting materials. These induce the flow of electrons in a certain direction across the junction, resulting in a usable electric current that can power electrical devices and be fed into the grid. In this way, the photovoltaic effect allows solar cells to directly convert sunlight into electricity cleanly and silently.

Solar Cell Materials

Solar cells are typically made from semiconductor materials that can convert sunlight into electricity. Here are some of the most common materials used:

Silicon – Crystalline silicon is the most widely used material for solar cells. It is made from silica, one of the most abundant materials on Earth.
Cadmium telluride – This is a thin-film material that absorbs sunlight well. It is less expensive than silicon.
Copper indium gallium selenide – Also called CIGS, this thin-film material has a high absorption rate but is more expensive.

Gallium arsenide – This material has a very high efficiency rate but is more complex and costly to manufacture.
Perovskites – An emerging thin-film material made from abundant low-cost materials, but still in early research stages.

The abundance and low costs of key component materials, especially silicon, make solar PV cells widely accessible and renewable.

Abundance of Materials

Solar cells are primarily made from silicon, a material that is very abundant on Earth. Silicon is the second most abundant element in the Earth’s crust after oxygen. It makes up about 28% of the crust by mass. With such a high natural abundance, there are vast reserves of silicon available for solar cell production.

Other common solar cell materials like boron and phosphorus are also relatively abundant. Boron is predicted to have a crustal abundance of 10 parts per million. Phosphorus has a crustal abundance of about 1,000 parts per million. While less common than silicon, supplies of boron and phosphorus are more than adequate for manufacturing solar cells.

Some solar cells incorporate more exotic materials like gallium arsenide. While rarer than silicon, the amount of these materials needed for solar cells is very small compared to global reserves. For example, indium is used in certain thin-film solar cells and has an estimated global reserve of 16,000 tons. Only a few grams of indium are needed per square meter of solar panel.

Overall, materials scarcity is generally not a concern for solar photovoltaic technology. The raw materials are relatively abundant and only small amounts are needed for each solar cell. With prudent use, supplies are sufficient to support large-scale solar cell production.

Production of Solar Cells

Solar cells are primarily made from silicon, a material that is very abundant on Earth. To produce solar cells, silicon is purified and formed into ingots or bricks. The silicon ingots are then cut into very thin wafers using wire saws or lasers. The wafers are then processed and doped with other materials to form the solar cell devices which can convert sunlight into electricity.

The manufacturing process for solar cells has become very efficient and scalable over the past few decades. Automated production lines allow solar cells to be mass-produced rapidly and at low costs. Many companies around the world have built large factories and facilities dedicated to solar cell and panel production. Total global production has increased from under 5 gigawatts in 2006 to over 100 gigawatts today, showing the scalability of the manufacturing process. And production costs have declined dramatically as a result of economies of scale and technology improvements.

Given the abundance of raw silicon materials and the inherently scalable nature of solar cell manufacturing, production can keep expanding to meet rising demand. As long as there is sunlight to fuel the growth of the solar industry, production of solar cells and panels can scale up indefinitely without any fundamental barriers to continued expansion.

Lifespan of Solar Panels

The lifespan of solar panels depends on the quality of manufacturing and materials used. Most solar panels are built to last 25-30 years or more. Many manufacturers provide 20-25 year power output warranties for around 80% of the panels’ original productivity. With proper maintenance, a solar panel system can remain productive for over 35 years.

There are a few factors that affect the lifespan of solar panels:

Manufacturing quality – Lower quality solar cells and wiring will degrade faster.

Panel technology – More advanced panels using monocrystalline silicon tend to last longer than older amorphous silicon models.
Climate conditions – Exposure to high temperatures, moisture, snow loads and hail can accelerate wear.
UV exposure – The ultraviolet radiation from the sun degrades materials over time.

Physical damage – Impacts from debris can crack panels and expose them to moisture.
Maintenance – Regular inspections, cleanings and repairs extend lifespan.

With ongoing maintenance and inverter replacements as needed, a high quality solar PV system can remain productive for 30-40 years or longer before requiring panel replacement.

Recyclability

At end of life, solar panels can be recycled and their materials reused, which makes them a renewable energy source. Most solar panel components like aluminum, glass, and semiconductor materials can be recovered and recycled. Recycling reduces waste going to landfills and also lowers the need for new raw material extraction and processing.

Silicon makes up the biggest portion of solar panels, and it can be reused to make new silicon wafers for solar cells. Other metals like silver and copper interconnects can also be recovered and reused. The encapsulant materials like EVA can be separated and recycled. Recycling processes are being improved to increase material recovery rates and purity.

There are some challenges with recycling, such as the need to disassemble panels and separate out the components. However, solar panel recycling is economically viable and some companies already provide recycling services. With rising recycling rates and processes, solar power can move towards a circular economy model. This supports its status as a renewable resource.

Ongoing Resource Use

Solar panels do require some ongoing resource use during their operation. The main resources needed are:

Water for cleaning – Solar panels need to be kept clean to maintain optimal efficiency. Water is used regularly to wash dust and dirt off the panels.
Land area – Solar farms require large plots of land to capture enough sunlight. The amount of land depends on the size of the installation.

Maintenance – Some maintenance activities like inverter replacement use additional resources over the lifespan of a solar farm. However, maintenance is minimal compared to fossil fuels.
Storage batteries – For solar energy to be dispatchable, storage systems like lithium batteries are needed. These require mining of resources like lithium, cobalt, and nickel.

However, the ongoing resource requirements are still vastly lower than extraction and transportation of fossil fuels. And unlike coal or oil, sunlight will never run out. So while solar power does need some ongoing inputs, it remains a renewable resource over human timescales.

Environmental Impact

When compared to fossil fuel energy sources like coal, oil and natural gas, solar photovoltaic cells have a much lower environmental impact over their lifetime. Fossil fuels produce large amounts of greenhouse gas emissions like carbon dioxide and methane when burned to generate electricity. These emissions are the leading cause of climate change. Solar panels produce no direct emissions when generating electricity from sunlight. The manufacturing process for solar panels does use some fossil fuels for mining raw materials and energy for production. However, it is estimated that solar panels “pay back” this embedded carbon footprint in just 1-4 years of operation through clean energy generation. After this payback period, they produce clean energy for decades. Solar panels also use very little water when compared to fossil fuels. Coal, nuclear and natural gas power plants require immense amounts of water for cooling and steam generation. The life cycle water usage of solar PV is over 200 times lower per kilowatt hour compared to these conventional power plants. With rising concerns about water scarcity globally, solar PV’s low water usage is a major advantage.

Conclusion

In summary, solar photovoltaic cells utilize abundant materials like silicon, which can be recycled and does not get consumed in the process of generating electricity from sunlight. The manufacturing process does require some inputs of energy and raw materials, but solar panels can last for decades and pay back the energy used in their production many times over. While some components may need replacing, the vast majority of a solar panel’s materials can be reused or recycled. There are some emissions and resource use associated with solar panel production, but the environmental impact over their lifespan is far lower than fossil fuel energy sources. Given the recyclability, abundance of source materials, and clean energy production, solar photovoltaic cells can be considered a renewable form of energy overall.