Focus | The era of photovoltaic "four can" is coming, is your power station ready?

Recently, the National Energy Administration officially issued the "Management Measures for the Development and Construction of Distributed Photovoltaic Power Generation" (hereinafter referred to as the "Management Measures"). The new regulations propose a "observable, controllable, measurable, and adjustable" technical standard system (referred to as photovoltaic "four can") for the first time, focusing on solving the bottleneck restricting the development of the industry and marking the entry of China's distributed photovoltaics into a new stage of high-quality development.

 

 

What is photovoltaic "four can"?

Photovoltaic "four can" refers to the observability, controllability, measurability, and adjustability of photovoltaic power generation systems. It can flexibly and rigidly control the output of photovoltaic power generation, achieve synergistic optimization of photovoltaic consumption capacity, and effectively solve the problems of reverse overload in substations and imbalance in on-site consumption.

Why does China have such requirements for distributed photovoltaic power stations? Will the "four can" transformation of power stations affect users' photovoltaic income? This move has attracted widespread attention from energy industry professionals and photovoltaic power station investors. To better answer these questions, Xiaoe will first use a picture to help everyone understand the general development history of China's distributed photovoltaics in recent years.

From the figure, we can see that the development of distributed photovoltaics has been booming, but it has also encountered "growing pains":

Difficult grid connection: Excessive distributed photovoltaics disturb the "calm waters" of the power grid

In the past, distributed generation played a "small and beautiful" role in the power system and was a useful supplement to the large power grid. Nowadays, under the policy benefits and capital operation, distributed photovoltaics have boomed and become a "big problem" in energy allocation. According to data from the National Energy Administration, by the end of 2024, the cumulative installed capacity of distributed photovoltaic power generation reached 370 million kilowatts, 121 times that of the end of 2013. In June 2023, the National Energy Administration required pilot provinces such as Shandong and Henan to assess the carrying capacity of the power grid for distributed photovoltaic access. The provinces published the assessment results, and more than 150 regions have no space for new distributed photovoltaic access.

To solve the challenges brought to the power grid operation by the "photovoltaic tide", such as reverse overload of transformers, voltage exceeding limits, and frequency fluctuations, it is necessary to implement a series of distribution grid upgrading projects such as active network transformation of lines, transformer capacity expansion, and power quality optimization. In addition, as the installed capacity of distributed photovoltaics exceeds the carrying capacity of the grid, the grid connection cost will also increase significantly. If the distributed photovoltaic power station continues to grow too fast, it will inevitably lag behind the speed of grid supporting transformation, thus leading to obstacles to photovoltaic grid connection.

Difficult consumption: Extensive access will lead to a crisis in new energy consumption

In terms of consumption, distributed photovoltaic power generation has two pairs of "innate" contradictions: one is the time contradiction, and the other is the space contradiction. In terms of time, photovoltaics can only generate power in good weather, especially during the midday period, which is basically during the low valley period of electricity consumption; in terms of space, distributed photovoltaics are mostly distributed in vast rural areas with large space and site resources, far from urban load centers, and have weak on-site consumption capacity, resulting in a situation of "large installation, small output" in local power grids.

According to statistics, the average per capita distribution transformer capacity in China's rural areas is about 3 kVA, and the average per capita electricity load is less than 2 kW, while the average per capita photovoltaic installed capacity is as high as 20 kW. For household photovoltaics, on-site consumption is even more difficult. However, under the numerous policy benefits such as subsidies for household photovoltaics and priority in settlement with the power grid, capital has flocked in and blindly developed, leading to the "photovoltaic fever" being difficult to subside, and the risk of excess new energy power generation is increasing. In addition, China's relatively low residential electricity prices have led to the fact that the income of most household photovoltaics fully accessing the grid is far greater than self-generation and self-use, resulting in insufficient user motivation for self-consumption and further increasing the pressure on the power grid.

Of course, the unexpectedly rapid development of distributed photovoltaics has also forced the industry to enter a new stage of standardized development earlier. The "Management Measures" put forward the "four can" construction requirements for distributed photovoltaics, which is a well-considered decision after repeated deliberation. Starting from the source of the power station, it further improves the ability of the power system to consume distributed photovoltaics and lays an important groundwork for the power station to participate in the electricity market in the future.

So, what specific roles do the "four can" transformations of distributed photovoltaic power stations play? Let's hear what experts think.

"Four can" control strengthens the foundation of dispatching

 

Shi Jingli, a researcher at the Energy Research Institute of the National Development and Reform Commission, pointed out in her interpretation article "Promoting the Scientific, Orderly, and Healthy Development of Distributed Photovoltaic Power Generation" on the "Management Measures" that for dispatching departments, power sources must have "four can" capabilities to participate in dispatching. For distributed photovoltaics to participate in the electricity market, having "four can" capabilities is a basic condition. More distributed photovoltaics with "four can" capabilities can significantly improve their grid connection capacity and controllability. Dispatching institutions can accurately and reasonably dispatch distributed photovoltaics, instead of being forced to cut off power when it is difficult to dispatch, and it is also conducive to power system stability and power supply safety.

Aerial photograph of a large-area distributed photovoltaic power station of Zhejiang Huayuan Jinbo Technology Co., Ltd. | Photographed by Wang Conghang

Standard foundation safeguards data security

 

In the article "Accelerating the Promotion of Distribution Network Construction to Support the High-Quality Development of Distributed Photovoltaics", jointly authored by Yu Jianghua, Wang Qing, Bai Hualin, and Zhang Tianyu of the China Photovoltaic Industry Association, the dual-protection path is emphasized. "While promoting 'four can', it is necessary to ensure the information security of data acquisition from power sources and distribution networks, ensuring the confidentiality, integrity, and availability of information interaction; on the other hand, it is also necessary to formulate technical standards and protocols suitable for distributed power sources accessing distribution networks to avoid the cost increase caused by inconsistent interface forms." "Distributed power sources that meet the 'four can' requirements should also have power control capabilities. Through distribution network optimization, reasonable grid protection and control strategies should be formulated to improve the distribution network's adjustment capabilities and promote the consumption of distributed power sources."

Staff from the State Grid Dongyang City Power Supply Company replace photovoltaic Internet of Things meters for distributed photovoltaic owners and install photovoltaic "four can" equipment | Photographed by Wu Yaqin

Intelligent control upgrade increases power station income

 

Through observable and measurable modifications, real-time monitoring and analysis of power plant operational data is achieved. Power plant owners can promptly identify and resolve equipment malfunctions, preventing power generation losses due to downtime. According to the "Research Report on Improving the Operational Efficiency of Distributed Photovoltaic Power Plants" released by the China Electric Power Research Institute, after the introduction of "four-enable" modifications, power generation efficiency has increased by approximately 5%, and annual revenue can increase by more than 8%. Through controllable and adjustable modifications, power plant owners can actively participate in grid peak shaving and other auxiliary power market services according to grid demand and market electricity prices, obtaining additional economic benefits. In addition, "four-enable" modifications can also reduce power plant operation and maintenance costs and extend equipment lifespan. According to power plant professional operation and maintenance manufacturers such as Zhejiang Zhengtai Zhiwei Energy Service Co., Ltd., "four-enable" modifications can effectively reduce the frequency of manual inspections, promptly identify equipment problems, reduce equipment replacement expenses, and the operation and maintenance costs are expected to decrease by about 20%.

Staff from the State Grid Dongyang City Power Supply Company help distributed photovoltaic owners install photovoltaic "four-enable" integrated wiring harnesses | Photo by Liu Suwei

Based on the views of professionals, it is not difficult to see that the "four-enable" transformation, by building a technical closed loop of "full data acquisition - precise instruction delivery - real-time response feedback", can not only increase the power generation revenue of distributed photovoltaic power plants but also enhance the load capacity threshold of the distribution network, ultimately forming an aggregation effect of millions of distributed resources "gathering sand into a tower".

In the wave of photovoltaic "four-enable" transformation, we will all be witnesses and participants. After listening to the above analysis, you must have a deeper understanding of photovoltaic "four-enable". Here, I also appeal to everyone: Let us work together to participate in the photovoltaic "four-enable" transformation and embrace a brighter future with smarter and healthier green energy!