The main factors contributing to the carbon footprint of solar panel manufacturing are the following:
- Energy-Intensive Raw Material Processing
– The production of polysilicon, a key raw material for solar panels, is highly energy-intensive. Extracting and refining silicon from quartz requires very high temperatures (1,500-2,000°C), leading to significant electricity consumption per kilogram of silicon produced.
– This stage often relies on coal-fired power plants, especially in major producing countries like China, which increases greenhouse gas emissions substantially. - Manufacturing Processes
– The processes involved in wafering (cutting silicon into wafers), cell fabrication, and module assembly consume large amounts of electricity.
– Monocrystalline solar panels demand more energy to produce than polycrystalline panels because of the energy-intensive Czochralski process used to create monocrystalline wafers. Despite this, monocrystalline panels have become more popular due to their efficiency.
– Energy efficiency improvements in polysilicon production, notably in the Siemens process over the last decade, have helped reduce energy usage by around 50%, thus lowering emissions per panel. - Transportation and Logistics
– Solar panels are often manufactured in China but shipped worldwide, especially to markets in Europe and North America. This global transportation contributes significantly to the carbon footprint due to fuel consumption during shipping, road, and rail transport.
– The weight of panels, influenced by components like glass and aluminum frames, affects fuel usage in transit, adding to emissions. - Material Efficiency and Technological Improvements
– Reductions in the use of certain materials, such as a one-third decrease in silver content per solar cell, have improved material efficiency, which contributes to lowering the carbon footprint.
– Increased use of renewable electricity in manufacturing countries like China, Germany, and the US has driven down emissions intensity over time.
– Overall, emissions per panel have fallen by about 45% between 2011 and 2021 due to these combined factors.
Summary Table of Main Carbon Footprint Factors
| Factor | Description | Impact on Carbon Footprint |
|---|---|---|
| Polysilicon Production | High temperature refining, coal-powered electricity | Largest contributor; energy-intensive |
| Wafering & Cell Fabrication | Energy-intensive manufacturing steps, more for monocrystalline | Significant energy use |
| Transportation | Shipping from production sites to global markets | Substantial emissions from fuel use |
| Material Usage | Amount of silver and other materials per panel | Reduced material use lowers footprint |
| Energy Source | Coal vs renewable in manufacturing electricity supply | Cleaner energy lowers emissions |
| Technological Improvements | Energy efficiency gains, process optimizations | Continuous reduction in emissions |
In conclusion, the carbon footprint of solar panel manufacturing is primarily driven by the energy-intensive production of polysilicon using fossil fuel-based electricity, the energy demands of wafer and cell manufacturing (especially for monocrystalline panels), and the emissions associated with transportation logistics. Improvements in material efficiency, renewable energy adoption in manufacturing, and advances in production technology have been effective in reducing emissions per panel over recent years.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-main-factors-contributing-to-the-carbon-footprint-of-solar-panel-manufacturing/
