There is little question that the solar market in general has thus far shown a growing preference for the LONGi Hi-MO 4 module with M6 wafer (166mm), but there are nevertheless still some in the PV industry who have an ambiguous attitude towards the product. In this article, we have put together a Q&A list on the LONGi Hi-MO 4 and trust that this will provide a more systematic and in-depth understanding of its background and benefits.
Why has LONGi chosen the M6 wafer (166mm) specification for the Hi-MO 4 module?
Figure 1: The reasons for choosing the M6 wafer (166mm) for Hi-MO4
The cost saving and compatibility advantages of the M6 wafer (166mm) are achieved at both the manufacturing end of the industrial chain and the application end of the system. For the cost saving on the system side, the fundamental reason is that the increase of current basically makes use of the margin of the current commercial inverter and increases the capacity of a single string for unchanged Voc (the string length is unchanged). Since M6 bifacial modules fully utilize the current margin of the inverter, any wafer larger than M6 will limit the inverter’s current and lead to a loss in power generation. Although new module circuit design can reduce current, the benefit in BOS cost will disappear when compared with M6 modules.
How has the LONGi Hi-MO 4 module evolved?
Figure 2: Upgraded Hi-MO4
LONGi optimized the design size of the Hi-MO 4 module earlier this year. The size of the 72 cell module changed to 2094 * 1038mm. The efficiency of mass produced modules exceeded 20% across the board, and that of the 450W module reached 20.7%. The improvement in efficiency brings further BOS cost savings, and the land area occupied by a power station is also significantly reduced.
What is the difference in BOS cost between the LONGi Hi-MO 4 module and modules of other specifications?
Figure 3: Comparison of main products in market (Bifacial Module)
With a 72 cell module with a 158.75mm silicon wafer, at a power station adopting a centralized inverter and fixed bracket configuration, the BOS cost of the Hi-MO 4 can be reduced by 0.65 US cents/W. Although the power of a 78 cell module is equal to that of the Hi-MO 4, the reduction in the number of series connections leads to a significant gap between the cost saving of its BOS and that of Hi-MO 4.
Figure 4: BOS cost comparison (Using string inverter)
At a power station adopting string inverters, the BOS cost of Hi-MO 4 can be reduced by 0.86 US cents/W due to the increase of capacity ratio.
LONGi’s Hi-MO 4 module is obviously larger. Can it really reduce installation costs?
Figure 5: Workers installing the LONGi Hi-MO 4 module with ease on a fixed bracket.
Obviously, a high power module with an M6 wafer (166mm) brings higher power generation gains and lower BOS costs in practical application. But will the increase in module size and weight make the actual installation more difficult? Will it add more installation costs?
According to detailed research, there is no obvious difference between a Hi-MO 4 module and a conventional module in terms of handling, upper bracket and installation work. However, due to the increase in power of a single Hi-MO 4 module, the number of modules required is lower, meaning that installation effort is reduced, efficiency improved, and the overall construction period shortened, significantly lowering overall installation costs.
What is the market performance of the LONGi Hi-MO 4 module?
LONGi’s Hi-MO 4 module has been in a state of relatively short supply since it was launched, with more than 10GW of cumulative orders and letters of intent. Shipments in 2019 reached 1.5GW. Projects where the Hi-MO 4 module has already been utilized cover, among other territories, all regions of China, Bangladesh and Vietnam. Feedback from customers and EPCs has generally been that significant savings have been seen in most aspects of the construction process.
The market response to Hi-MO 4 has been extremely positive. In 2020, the capacity of the module will exceed 20GW, ensuring stable global supply.
After continuous optimization, the Hi-MO 4 module has an impressive mass production version, with a further reduction in weight. With the addition of bifacial technology, BOS and LCOE costs have also been lowered. The LONGi Hi-MO 4 module has quickly become the preferred choice for global clients, especially for large-scale PV power plant investors, and has demonstrated huge investment value worldwide.