Under the “Dual Carbon” goals, solar power generation is often referred to as “zero-carbon clean energy,” and many people believe it produces no carbon emissions at any stage. In fact, this is not the case. The “zero-carbon” attribute of solar power only refers to near-zero emissions during the power generation stage. From a full life cycle perspective, a certain amount of carbon emissions will be generated, from raw material extraction to component scrapping and recycling. Understanding this truth helps us objectively evaluate its environmental value and promote the green upgrading of the photovoltaic industry.
To understand the full life cycle carbon emissions of solar energy, it is necessary to clarify its five core stages, each with distinct carbon emission intensity and sources, which are broken down in detail below.
I. Core Stages: A Detailed Explanation of Carbon Emissions at Each Stage
1. Raw Material Extraction and Processing: The “Source” of Carbon Emissions
The core raw material of photovoltaic panels is silicon, and its extraction and processing constitute a major source of carbon emissions in the full life cycle. The production of silicon involves multiple processes such as quartz sand purification and ingot cutting. Among these, smelting quartz sand into industrial silicon and purifying industrial silicon into polysilicon consume large amounts of energy and generate carbon emissions.
In traditional polysilicon production, each ton generates approximately 8-12 tons of COâ‚‚ equivalent, while advanced processes can reduce this to 3-5 tons. The extraction and production of raw materials for photovoltaic panels, such as glass and aluminum frames, also produce a small amount of carbon emissions.
2. Component Production and Manufacturing: The “Core Link” of Carbon Emissions
After the raw materials are processed, they enter the component production link, including wafer cleaning, cell preparation, component packaging and other processes. The carbon emissions in this link mainly come from two aspects: one is the electrical energy consumed in the production process (such as the operation of equipment for cell coating and component lamination), and the other is the preparation and consumption of chemical reagents (such as passivators and packaging adhesives) used in the production process.
There is a significant difference in carbon emission intensity during the production stage among photovoltaic components of different technical routes. Taking the mainstream PERC components as an example, the carbon emissions per watt of components produced are about 0.8-1.2 kg of CO2 equivalent; while the high-efficiency HJT and TOPCon components, due to their more complex production processes and higher energy consumption requirements for equipment, have a carbon emission of about 1.0-1.5 kg of CO2 equivalent per watt. However, with the upgrading of component production processes and the increase in the proportion of clean energy (photovoltaic, wind power) in production electricity, the carbon emissions in this link are continuously decreasing.
3. Power Station Construction and Installation: Hidden Carbon Emissions
The carbon emissions in the construction and installation of photovoltaic power stations are relatively hidden but cannot be ignored. They mainly come from two aspects: one is the production and transportation of building materials such as cement and steel, and the other is the fuel consumption of construction equipment (such as cranes and excavators), both of which produce a small amount of carbon emissions. However, the proportion of carbon emissions in this link is extremely low, usually only 5%-8% of the total carbon emissions in the full life cycle, and can be further reduced by using green building materials and new energy construction equipment.
4. Power Station Operation and Maintenance: A Low-Emission Continuous Link
The operation and maintenance stage of photovoltaic power stations has the lowest carbon emission intensity, mainly derived from the energy consumption of operation and maintenance equipment (such as cleaning robots and inspection vehicles), and the carbon emissions indirectly generated by the consumption of a small amount of water resources during component cleaning. Under normal circumstances, the annual carbon emissions in this link only account for 1%-3% of the total carbon emissions in the full life cycle, and will further decrease with the popularization of intelligent operation and maintenance (such as drone inspection).
5. Component Scrapping and Recycling: The Easily Ignored “Terminal Emissions”
The service life of photovoltaic components is about 25-30 years. If not properly handled after scrapping, they will become a new source of carbon emissions. Traditional landfill and incineration methods will release a small amount of pollutants and carbon emissions; standardized recycling can realize the reuse of resources such as silicon material and glass, greatly reducing emissions, but the recycling process itself (such as component disassembly and material purification) still needs to consume a small amount of electrical energy, generating trace carbon emissions. At present, China’s photovoltaic recycling system is gradually improving, which has been able to control the emissions in this link at a low level.
II. Key Clarification: The True Meaning of Solar “Zero-Carbon”
In summary, solar power generation is not “absolutely zero-carbon”, but “relatively zero-carbon” — its full-life-cycle carbon emissions are much lower than those of traditional energy sources such as thermal power and natural gas power generation. Data shows that the full-life-cycle carbon emissions of photovoltaic power stations are about 30-50 grams of CO2 equivalent per kilowatt-hour, which is only less than 1/20 of that of thermal power (about 800-1000 grams).
The “zero-carbon” of solar energy in people’s mouths mainly means that its power generation link (converting sunlight into electricity) produces almost no carbon emissions, and no pollutants are emitted during the power generation process. With the upgrading of the photovoltaic industry, the reduction of energy consumption in silicon material production, the replacement of clean energy, and the improvement of the recycling system, the full-life-cycle carbon emissions of solar energy are still continuously decreasing, and its environmental advantages are becoming more and more prominent.
III. Conclusion: View Rationally and Promote a Greener Photovoltaic Industry
Uncovering the truth about the full-life-cycle carbon emissions of solar energy is not to deny its environmental value, but to understand it more rationally and objectively. Compared with traditional fossil energy, the low-carbon advantage of solar energy is undeniable, and it is still the core force to achieve the “dual carbon” goals. In the future, through technological innovation to reduce carbon emissions in various links and improve the component recycling system, solar power generation will be closer to “true zero-carbon”, providing more solid support for the global energy transition.