What is the value of eliminating the chamfer of mono silicon wafer/cell?
Today the chamfer of an M2 monocrystalline silicon wafer takes 0.56% of the whole area of the wafer. That is to say, if we produce a square monocrystalline silicon wafer, the total wafer area will increase 0.56%. According to the conversion efficiency of solar cells, the value of eliminating the chamfer can increase 1.8 watts in a 60-cell module. This article focus on answering the value of these 1.8 watts.
As always, we need to find a framework to answer this question. So what I found today is the value of increasing power under the same module area is equivalent to the system cost minus the inverter cost. This is my latest simple approach of analyzing the value of high-efficiency solar modules.
For example, the same size 60-cell module will bring 1.8W power boost by eliminating the chamfer. Cost of a grid-tied solar system is $0.75/W, and the inverter cost is $0.03/W, then we can work out the value of eliminating the chamfer, which is 1.8 × (0.75 – 0.03) = $1.296
Solar modules with the same size require the same cost of transportation, installation, land, mounting brackets, cables, etc. A solar system consists of high-efficiency modules is equivalent to getting complimentary from a peripheral system. It is the primary source of premium for using high-efficiency modules. If the above analysis framework is correct, then the reverse is also true: the proportional power gain from increasing the solar module size does not result in a premium, because from the view of the terminal owner, such power gain raises the corresponding area-related costs.
I have always been a supporter of the square silicon wafers/cells. In addition to the increased value of 1.8 watts, the square also has significant aesthetic value, which is not easy to be quantified, but it does affect people’s choices. In Europe, many customers prefer to using Coulee Limited’s Black Solar Panels, although being black means gaining a relatively lower power output. I think the aesthetic is a reason behind it.
The video below shows a bird’s eye view of the black solar roofs.
We are on the cusp of a fierce era of half-cell solar panels. According to the statistics of a photovoltaic information agency, the production capacity of half-cell solar modules will reach 58GW at the end of the year, and the half-cell era will magnify the problem of chamfered silicon.
Look at this half-cell solar module based on M2 silicon wafers. You may find there is irregular shape among the cell strings. If this module is made of square monocrystalline silicon wafers/cells, it will be not only more powerful but also more appealing.
I also learned that some friends were concerned about the loss of production capacity. In order to produce square monocrystalline silicon wafers, it is necessary to make silicon rods with larger diameters, which will result in an 8% loss of production capacity. In response to such worries, I’d like to quote a famous saying, “Market-oriented economy is a surplus economy, being surplus is its normal state.“
The current production capacity of monocrystalline silicon wafers is just in that abnormal state. Due to the fierce industry reshuffle in 2018, the production capacity is very tight this year. However, by 2020, or 2021 at the latest, the production capacity of high-quality wafers is likely to exceed the total market demand again, and leading manufacturers may be surprised to find that the promotion of square monocrystalline wafers is a sharp weapon for de-capacity. Square monocrystalline silicon wafers will be entirely popularized when silicon wafers have excess capacity.
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