With the economic value of solar PV projects of 25 years, the question is what to do to handle the large number of solar cells after their expiration date. This article will help readers to reconsider in a proper way when viewing solar cells as waste (when expired, damaged)
I. Opening
Renewable energy plays an important role in replenishing and meeting a significant part of human increasing demand of energy. This is a very rich resource, available in nature and in many common forms. In particular, solar energy is an infinite source of energy that can be exploited all over the world, they are emerging as an ideal complement to other traditional energy sources.
According to the Institute of Energy – Ministry of Industry and Trade, the solar power potential in Vietnam is about 1677.5 GW. According to the current situation, it is required by 2030, a total of 385.8 GW of solar power should be put into operation for the country’s economic development. According to World Bank, the rooftop solar power potential in Ho Chi Minh City is 6.3 GW, and Da Nang is 1.1 GW. With such great potential, some false information and negative opinions can hinder the development of solar power in Vietnam.
Many people believe that expired solar cells will become hazardous waste for the environment and need to be disposed. So why are expired solar batteries considered hazardous waste?
II. Why are expired solar batteries a hazardous waste? Is it mistaken to say that expired solar cells are hazardous waste?
To answer these questions, first of all, we need to consider what the main components of solar panels are?
a. Components of solar panels:
Solar cells or photovoltaic cells (Solar panel /module) are composed of many photovoltaic cells (solar cells) – a semiconductor element on the surface a large number of sensors that are photodiodes, which convert the energy of light into electrical energy.
Today, the main material for making photovoltaic cells (solar cells) is crystalline silicon (monocrystalline, polycrystalline) or thin silicon film. Photovoltaic cells (solar cells) are assembled into blocks to become solar cells (solar panel). Typically, there are 60 or 72 photovoltaic cells per solar panel.
Solar battery structure.
The main materials of solar panels (solar panel)
- EVA (Encapsulant) film is a thin film layer that creates a firm bond between photovoltaic cells (solar cell) and toughened glass /polymer coating (backsheet) to protect against impact and improve longevity of optical cells (solar cell). EVA is a polymer material (Ethylene Vinyl Acetate Copolymer), which is combined between Ethylene and Acetate and is produced through polymerization under very high pressure, widely used in the garment, footwear, supporting industries…
- Solar cell is a crystalline silicon sheet (monocrystalline, polycrystalline) or thin silicon film that is the main element of the solar cell.
- Polymer coating (Backsheet) is a layer that protects the underside of the solar cell to avoid environmental abrasion. Most solar cell manufacturers use PVF (Polyvinyl fluoride) to make Backsheet. PVF is a polymer material mainly used in aircraft interiors, raincoats … Some more advanced batteries use a toughened glass “Backsheet” layer (double glass type).
- Junction box: The box is normally a polymer that is heat resistant, fireproof, weather resistant, anti-aging UV … The connectors in the box are usually made of brass, coated with silver, or covered with tin.
- Conductors (Wiring) link between photovoltaic cells (solar cells) and link with electrical junction boxes. These conductors are made of copper or silver.
In the above structural components, tempered glass panels and photovoltaic cells are produced from sand with mainly silicon oxide (SiO2), which is the material to produce common items in everyday life. like a glass food bottle..
b. Is it mistaken to say that: Expired solar batteries are hazardous waste?
It can be noticed that: The main structural component of the solar cell is totally free from harmful substances. So where is the reason that many information says: Expired solar cells will become hazardous waste and need treatment measures?
Perhaps this incorrect statement comes from the name of solar power as “PIN” in Vietnamese. When it comes to the word “PIN”, people immediately think of normal charged types of batterries. This word “PIN” in French is “PILE” or “ACCU”, or called in Vietnamese as “Batteries”. Lead-acid “Batteries” have been commonly used charged devices for hundreds of years.
All PINs for charged use, similar to flashlights or batteries, are considered hazardous waste and need to be collected for disposal. Therefore, when referring to PIN, people immediately think of hazardous waste, so the solar cell becomes the victim of this naming (“PIN MẶT TRỜI”). So why name it “PIN MẶT TRỜI” without using another name without the word “PIN”? Where does the name “PIN MẶT TRỜI” come from? This question is really difficult to answer, but in the opinion of the author, it probably comes from the word “CELL”.
In today’s daily life, when we buy / replace batteries for laptops, for some cell phones … we often ask “How many cells does this battery have?”, “4 or 6 cells?”… This is a technical term to simply describe the battery’s capacity. Structure and operating principle of batteries and solar cells have many specific similarities such as batteries are derived from cell-module-rack-system, while batteries are cell-module/panel-array/table system. So perhaps the naming of the word “PIN” for solar power systems comes from this similarity.
Research and assessment of countries around the world and solutions to the expired solar cell waste
Thus, “PIN MẶT TRỜI” is not a hazardous waste and is confused by naming. So the question is, how do countries around the world view this? The author has learned about this issue and would like to provide the reader with some reference information from the surveys and research of prestigious organizations in the world as below.
1/ According to SolarTech (USA): PV panel life lasts 20-30 years, some solar panels from the 1970s and 1980s are still in use. Many control agencies in the US and its states have conducted experiments to test the danger to the environment, but most products have passed these tests and cannot be categorized as hazardous waste. Measures for expired panels: separating the materials that make up the panel (glass, cell, metal, plastic /polymer) for reuse. For example, glass panels are used to make bottles, the cells are chemically disposed so that factories can reuse to produce new cells with higher efficiency…
In a nutshell, according to SolarTech, in the US, the solar panels that are no longer in use (due to expiration, failure, etc.) are not considered hazardous waste but a resource as input materials to produce new solar cells, or for other purposes.
2/ According to IEA Photovoltaic Power Systems Programme – IEA PVPS (Switzerland): This organization has surveyed and studied the processing of solar cells that have expired for a long time and in many countries. According to documents published by this organization, the response and assessment in countries are as follows:
– EU: Regulations on the rate of recycling and reusing solar cells in the EU is 85%/80%.
– USA: There are currently no laws regulating the management of expired PV panels
– Japan: There is no specific regulation on the disposal of expired solar cells, panels that must be disposed (if no longer in use) are processed as ordinary solid waste (harmless). In Japan, these panels are also recycled for use.
– China, Korea: There are similar reviews as above.
The life of PV panels extends to 30 years and the majority continues to operate. All materials that make up the solar panel are recovered and reused. The materials are considered resources, not hazardous waste. IEA PVPS documents also provide information on treatment technologies for recycling and reuse in countries for different types of PV. Countries have also been researching technologies for efficient, low-cost recycling, and reduced recycling time…
III. Opinions of the authors
First: There is confusion when naming solar power as “PIN”, leading to conflicting information that “PIN MẶT TRỜI” is a hazardous waste.
Second: Expired solar cells will not be hazardous waste but a resource for reuse for the purpose of producing new solar cells with higher quality and cheaper price. In addition, it can also be used for other purposes.
Third: The life of solar cells is very long 20-30 years, solar cells from the 1970s and 1980s are still in use. Therefore, the amount of solar cells in the world that need to be processed is quite small compared to the scale produced and mainly due to defects and failures. In Vietnam, it might take 20-30 years to start considering the plan to handle expired solar panels.
Fourth: Vietnam is considered to be a potential place to develop solar power on a very large scale, so there is a need for strong propaganda for people to properly understand the nature of solar cells and to support solar power development in Vietnam.
Source: Dao Minh Hien, Director of R&D-PECC2 Center and nangluongvietnam.vn
