At present, many versions of the calculation data of photovoltaic carbon emissions do not include carbon emissions from silica sand to metallurgical silicon, but from metallurgical silicon materials to photovoltaic systems, including research reports prepared by Li Junfeng. I estimate that because silicon is a raw material for Guangpu industry, such as semiconductors and chemicals, the photovoltaic industry chain begins to calculate from silicon. However, it must be pointed out that the process of reduction of silica sand SiO2 to metallurgical silicon has a large amount of direct emission of CO2 (SiO2+2C=Si+2CO, 2CO+O2=2CO2). A small group of people attacked PV to conceal carbon emissions. I recalculate the carbon emissions from the silica sand to the entire industrial chain of the photovoltaic system. I have exhausted all the related auxiliary materials, packaging materials (tempered glass, EVA, TPT, etc.), photovoltaic system integration equipment (connected network control inverter, cable, The energy consumption of production, such as switches, brackets, and meters, and their carbon emissions are positively viewed.
Before you calculate, you must introduce a few simple concepts to help you understand the calculation method:
1. Carbon Footprint refers to a collection of greenhouse gas emissions caused by a business, activity, product or individual. The main greenhouse gas emission channels are: transportation, food production and consumption, energy use and various production processes. Usually all greenhouse gas emissions are expressed in terms of carbon dioxide equivalent (CO2e). Often referred to as "carbon consumption."
2. Greenhouse Gas (GHG) refers to the gas component of the atmosphere that contributes to the greenhouse effect. The greenhouse gases mainly include carbon dioxide (CO2), ozone (O3), methane (CH4), nitrous oxide (N2O), and artificial greenhouse gas chlorofluorocarbons (CFCs), perfluorocarbons (PFCs), and hydrofluorocarbonization. (HFCs), chlorofluorocarbons (HCFCs) and sulfur hexafluoride (SF6).
From the metallurgical silicon material to the polysilicon production process, there is a direct discharge of toxic gases such as hydrogen chloride exhaust gas (of course, there are corresponding recycling treatment measures), but there is no greenhouse gas emissions. There is also no greenhouse gas emissions from the production process of polycrystalline silicon ingots to photovoltaic systems (there are very few toxic gases that have been treated before discharge).
3. Calculation method
1) Indirect carbon emission: refers to the carbon equivalent emission calculated by the conversion of electricity consumption of production equipment. Here, it mainly refers to the carbon equivalent emission calculated by the conversion of power consumption such as polysilicon reduction, cutting, component packaging, and system integration installation. The industrial chain power consumption data is taken from the [photovoltaic energy recovery period calculation table].
The commonly used formula is: electricity consumption × electricity carbon emission factor = indirect carbon emissions
2) Direct carbon emission: refers to the amount of greenhouse gas directly discharged during the production process of the battery industry chain. This refers to the amount of CO2 directly discharged from the process of silicon sand reduction to metallurgical silicon.
According to calculations, from the perspective of the polysilicon photovoltaic industry chain (silica-photovoltaic power station system), the average carbon emissions per degree of photovoltaic power generation is only 47.32gCO2/KWH, which is about 10-17 of the traditional fossil energy power generation. Photovoltaic power generation is a true low carbon energy source.
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