Central enterprises account for more than 70% of the centralized procurement, and string inverters usher in the "best era"

As system costs continue to fall, photovoltaic power generation is entering an era of parity or even low prices. Many consulting agencies, such as the International Renewable Energy Agency and Bloomberg New Energy Finance, believe that even without financial subsidies, renewable energy is currently the cheapest source of power generation. Behind this is the accelerated iteration of photovoltaic product technology and the continuous decline in costs, in which photovoltaic component and inverter companies have made great contributions.

As an indispensable key electrical equipment in photovoltaic power generation, inverters have undergone multiple industry reshuffles, technological innovations, and cost optimizations in the past decade. Taking string inverters as an example, the SunnyTripower 17000TL launched by SMA in 2010 had a rated power of 17KW, which was almost the most cutting-edge product at the time; but by 2020, China's leading inverter companies have launched multiple models of high-power string products, which are fully suitable for large-scale photovoltaic power stations and have achieved significant upgrades in intelligence, overload rate, and DC input.

In 2013, Huawei entered the photovoltaic industry with string inverters, bringing a breath of fresh blood to the photovoltaic inverter field. As a "rising star" in the inverter field, string inverters have begun to rise to a mainstream position in the large ground power station market in recent years with their excellent power generation performance and gradually narrowing price gap with centralized inverters. At the same time, inverter manufacturers that previously mainly promoted centralized inverters have also begun to deploy string inverters.

According to third-party data, string inverter shipments have surpassed centralized inverter shipments since 2017, and have gradually become the absolute mainstream in the industry. Recently, the world's largest single photovoltaic power station with a capacity of 2.2GW invested and built by Huanghe Company was connected to the grid. According to PV people, the project uses string inverters.

PV people counted the bidding of central power enterprises in the first half of 2020. Among the total bidding capacity of 24.3GW, string capacity exceeded 18GW, accounting for 74.3% of the total bidding capacity.

Note: The above only covers some of the larger-scale inverter bidding situations, among which China National Nuclear Corporation is counted according to the largest bidding scale.

Obviously, string inverters are gaining more and more favor among owners. A research and development manager who has been in the industry for more than 10 years believes that if the price of power electronic components is further reduced in the future, the competitive advantage of string inverters will be more obvious. In addition, compared with centralized inverters, string inverters have the advantages of multiple MPPTs and can more accurately identify each string fault, accurately operate and maintain, and greatly improve efficiency.

"At present, the advantages and disadvantages of string and centralized inverters are very obvious. Taking centralized inverters as an example, the average price per watt is relatively cheap, the single-unit conversion efficiency is as high as 98.5% or more, the inverter itself has low power loss, the AC side wiring is simple and low-cost, and the line loss is small. However, the disadvantages are also obvious - the IP level is relatively low (resulting in higher costs such as operation and maintenance dust removal), the MPPT tracking accuracy is not high enough, and the power generation is significantly affected by failures; the advantage of string inverters is that multi-channel MPPT improves tracking accuracy, the conversion efficiency is up to 99%, and the impact of single-string component failures is relatively low. The protection level has generally reached IP65 or even IP66 and above, and the operation and maintenance cost is relatively low. Moreover, compared with the centralized type, the end-to-end support of the system is basically the same," the above-mentioned person in charge explained. On the whole, there is more limited room for improvement in the disadvantages of centralized inverters, which is why developers and owners are gradually choosing string inverters.

As mentioned above, from the perspective of the prices of centralized and string inverters, the price difference between the two is gradually narrowing, especially in the past five years, multiple changes in the inverter landscape, the 531 policy, and fierce competition in the overseas market have brought continuous pressure on the price competition of inverters. PV people compared the key bidding projects from 2012 to 2020, including the prices of inverters of the winning candidates or the winners of the bid announcement. It can be found that the price difference between centralized and string inverters is gradually narrowing from 0.17 yuan/watt in 2016 to less than 0.5 cents.

On the other hand, string inverters are also gaining more favor from owners and developers of large-scale photovoltaic power stations. The head of the new energy department of a power design institute told PV people, "Among the three mainstream inverters, the price of the distributed type has exceeded that of the string type, so it is less used at present. This can also be verified from the results of this year's bidding. The price difference between string and centralized types has become smaller and smaller, close to three cents per watt or even lower. As the single-unit capacity of string types becomes larger and larger, many owners currently tend to choose string inverters. In particular, the advantages of string inverters are also very obvious, especially in terms of power generation income and operation and maintenance."

However, the above-mentioned person also added, "As the power of components increases, the difficulty of selecting inverters increases accordingly, so both centralized and string types are facing continuous technological upgrades. Obviously, there is still room for further reduction in the cost of inverters, so it is not possible to determine which type of inverter will definitely stand out in the competition."

From the perspective of equipment selection, there are many factors to consider. The head of a design institute told PV people, "The design and selection of photovoltaic power stations need to consider many factors, in addition to terrain, light conditions, installation type, the needs of the owner and developer and even related financing terms, etc., so the final implementation of the selection of components, inverters, brackets and other products is to make the overall power generation expectations of the power station reach the best."

In 2019, the global photovoltaic inverter market has exceeded US$9 billion, with shipments reaching 127GW. According to Wood Mackenzie data, the top 10 global shipments are Huawei, Sungrow, SMA, Power Electronics, Fimer, Sineng Electric, SolarEdge, Growatt, TMEIC, and Ginlong Technology, with Chinese brands occupying half of the market. In the past few years, Chinese inverter companies have made efforts both internally and externally, and their products basically cover the 3-30KW household series and 30-250KW string series.

The update and iteration of products and technologies is the most powerful driving force for the photovoltaic industry to participate in the competition in the power market. As one of the key equipment, inverters are deeply involved in it. With the diversification of photovoltaic application scenarios, various types of products will play the greatest value in their areas of expertise. However, there is no doubt that with the increase in grid penetration and the introduction of requirements such as the addition of energy storage in the future, the competition faced by inverters is also gradually intensifying.