Whether the future development of photovoltaics is smooth, energy storage is the key factor
time：2018-09-29
Although China's new energy has developed rapidly in recent years, the phenomenon of abandoning wind and abandoning light still exists. How to integrate fragmented green energy has become the key to the development of the industry.
The biggest change in the industry in the first half of the year was that on May 31, 2018, the three departments jointly issued the "Notice on Matters Related to Photovoltaic Power Generation in 2018" (referred to as "531 New Deal"). The document clearly stipulates that the scale of ordinary photovoltaic power plants will be arranged in 2018. The construction of distributed photovoltaic projects will be arranged at around 10GW, and the on-grid price of newly-operated photovoltaic power plants will be reduced by 0.05 yuan per kWh. ,
The introduction of the New Deal led to the market being extremely pessimistic about the later development of photovoltaics. Some investors discussed whether the direction of the national new energy policy has undergone fundamental changes. We believe that subsidy pressure is the main reason for the introduction of the New Deal. However, the introduction of the New Deal does not mean that the state will restrain the development of the industry, but to promote the healthier and sustainable development of the industry and promote the accelerated price parity of the industry. Although the introduction of the New Deal has brought about a rapid decline in the price of the industrial chain, it is not a good thing to exchange short-term pain for a more sustainable development space in the future.
Affected by China's policies in 2018, the world's new installed capacity may see its first decline since 2012, but it is expected to return to growth in 2019. According to the data, the proportion of photovoltaic power generation in total power generation has increased from 1.1% in 2016 to 1.8% in 2017. The future development of the photovoltaic industry is huge.
There are three challenges in distributed PV access:
1. Due to the lag in the construction of the security access zone and the lack of management, the distributed PV information collection rate is low, and the data is in real-time and reliable.
2. The construction of new energy modules in the regional intelligent dispatch control system lags behind, and the distributed PV power forecasting and scheduling lacks support;
3. Distributed PV has not been connected to the county AVC system, and distributed PV scheduling cannot be realized.
Introduction to photovoltaic energy storage system: Photovoltaic energy storage power generation system can improve power system stability and power consumption integrity. In the photovoltaic energy storage power generation system, the solar module absorbs sunlight, and the generated direct current is converted into alternating current by the inverter, and is stored in the energy storage unit for illumination by the household appliance. Excess electricity generation can be uploaded to the grid to obtain corresponding electricity price income and government subsidies. In addition, the energy storage inverter also has the function of peak clipping and valley adjustment, which can create more power generation benefits.
Working mode of photovoltaic energy storage system
Photovoltaic power generation has a high level of output in the short-term at noon, low output in other periods, and a strong output between the daytime and no power at night. The energy storage technology has the characteristics of real-time energy-shifting, and the photovoltaic power station is equipped with a photovoltaic midday. The output will be transferred to other time periods to reduce the power station's output peak and reduce the abandoned light.
In the working process of the battery energy storage system, the principle of minimizing the number of charge and discharge of the energy storage system is to extend the service life of the energy storage system. During the peak period of photovoltaic power generation, the battery energy storage system is controlled to be charged, and the output of the photovoltaic power station is peaked. After the peak period of photovoltaic power generation, the discharge of the battery energy storage system is controlled, and the discharge control of the energy storage system can assist the smoothing of the fluctuation of the photovoltaic output and the peaking of the auxiliary system to maximize the energy storage. According to the different functions of energy storage discharge, three working modes of energy storage system can be divided, which are peak clipping, peak clipping + smoothing and peak clipping + transfer problem style.
Working mode 1: cutting peak
In the peak period of photovoltaic power plant output, the peak energy is used as the application target to control the charging of the battery energy storage system. After the peak period of photovoltaic output, and during the photovoltaic power generation period, the battery energy storage system is controlled to be amplified and discharged to the battery energy storage system. The lower limit of SOE working range, then the energy storage system stops working, and the working time of the energy storage system is guaranteed. During the power generation time of the photovoltaic power station, the working time of the photovoltaic power station is not increased, and the work arrangement of the photovoltaic power station is reduced. Impact.
Working mode 2: peaking + leveling
During the peak output period of the PV power plant, the peak energy is used as the application target to control the charging of the battery energy storage system. The output fluctuations of large-scale photovoltaic power plants can be divided into two categories. One is the slow change of PV power plant output, such as the cyclical change of PV power plant output caused by day and night alternation; the other is the sudden change of PV power plant output, such as cloud cloud blockage. The sudden drop in the output of photovoltaic power plants. The first round of changes is large, but the change is slow; the second type of change is unpredictable and sudden, and in severe cases, the output is reduced from full to less than 30% of the rated value within 1~2s. After the peak period of photovoltaic output, in the process of smooth day and night alternation, the fluctuation of the output of the photovoltaic power station is the target to control the discharge of the energy storage system, discharge to the lower limit of the SOE working range of the battery energy storage system, and if it has entered the night, the output of the photovoltaic power station is reduced. By 0, the SOE of the energy storage system is still greater than 0.2, and the energy storage system is controlled to discharge at a constant power of rated power to SOE to 0.2, and then the energy storage system is controlled to stop working.
Working mode three: peak clipping + transfer
During the peak output period of the PV power plant, the peak energy is used as the application target to control the charging of the battery energy storage system. The output period of the photovoltaic power station is 8:30~18:30, and the late peak of the load appears between 18:00~22:00. During this period, the photovoltaic power station has basically no output, which can be assisted by controlling the discharge of the battery energy storage system. System peaking, in order to reduce the number of operation of the energy storage system and simplify the operation of the battery energy storage system, control the battery energy storage system to discharge at a constant power, discharge the lower limit of the SOE working range of the battery energy storage system, and then stop the energy storage system jobs.
The biggest change in the industry in the first half of the year was that on May 31, 2018, the three departments jointly issued the "Notice on Matters Related to Photovoltaic Power Generation in 2018" (referred to as "531 New Deal"). The document clearly stipulates that the scale of ordinary photovoltaic power plants will be arranged in 2018. The construction of distributed photovoltaic projects will be arranged at around 10GW, and the on-grid price of newly-operated photovoltaic power plants will be reduced by 0.05 yuan per kWh. ,
The introduction of the New Deal led to the market being extremely pessimistic about the later development of photovoltaics. Some investors discussed whether the direction of the national new energy policy has undergone fundamental changes. We believe that subsidy pressure is the main reason for the introduction of the New Deal. However, the introduction of the New Deal does not mean that the state will restrain the development of the industry, but to promote the healthier and sustainable development of the industry and promote the accelerated price parity of the industry. Although the introduction of the New Deal has brought about a rapid decline in the price of the industrial chain, it is not a good thing to exchange short-term pain for a more sustainable development space in the future.
Affected by China's policies in 2018, the world's new installed capacity may see its first decline since 2012, but it is expected to return to growth in 2019. According to the data, the proportion of photovoltaic power generation in total power generation has increased from 1.1% in 2016 to 1.8% in 2017. The future development of the photovoltaic industry is huge.
There are three challenges in distributed PV access:
1. Due to the lag in the construction of the security access zone and the lack of management, the distributed PV information collection rate is low, and the data is in real-time and reliable.
2. The construction of new energy modules in the regional intelligent dispatch control system lags behind, and the distributed PV power forecasting and scheduling lacks support;
3. Distributed PV has not been connected to the county AVC system, and distributed PV scheduling cannot be realized.
Introduction to photovoltaic energy storage system: Photovoltaic energy storage power generation system can improve power system stability and power consumption integrity. In the photovoltaic energy storage power generation system, the solar module absorbs sunlight, and the generated direct current is converted into alternating current by the inverter, and is stored in the energy storage unit for illumination by the household appliance. Excess electricity generation can be uploaded to the grid to obtain corresponding electricity price income and government subsidies. In addition, the energy storage inverter also has the function of peak clipping and valley adjustment, which can create more power generation benefits.
Working mode of photovoltaic energy storage system
Photovoltaic power generation has a high level of output in the short-term at noon, low output in other periods, and a strong output between the daytime and no power at night. The energy storage technology has the characteristics of real-time energy-shifting, and the photovoltaic power station is equipped with a photovoltaic midday. The output will be transferred to other time periods to reduce the power station's output peak and reduce the abandoned light.
In the working process of the battery energy storage system, the principle of minimizing the number of charge and discharge of the energy storage system is to extend the service life of the energy storage system. During the peak period of photovoltaic power generation, the battery energy storage system is controlled to be charged, and the output of the photovoltaic power station is peaked. After the peak period of photovoltaic power generation, the discharge of the battery energy storage system is controlled, and the discharge control of the energy storage system can assist the smoothing of the fluctuation of the photovoltaic output and the peaking of the auxiliary system to maximize the energy storage. According to the different functions of energy storage discharge, three working modes of energy storage system can be divided, which are peak clipping, peak clipping + smoothing and peak clipping + transfer problem style.
Working mode 1: cutting peak
In the peak period of photovoltaic power plant output, the peak energy is used as the application target to control the charging of the battery energy storage system. After the peak period of photovoltaic output, and during the photovoltaic power generation period, the battery energy storage system is controlled to be amplified and discharged to the battery energy storage system. The lower limit of SOE working range, then the energy storage system stops working, and the working time of the energy storage system is guaranteed. During the power generation time of the photovoltaic power station, the working time of the photovoltaic power station is not increased, and the work arrangement of the photovoltaic power station is reduced. Impact.
Working mode 2: peaking + leveling
During the peak output period of the PV power plant, the peak energy is used as the application target to control the charging of the battery energy storage system. The output fluctuations of large-scale photovoltaic power plants can be divided into two categories. One is the slow change of PV power plant output, such as the cyclical change of PV power plant output caused by day and night alternation; the other is the sudden change of PV power plant output, such as cloud cloud blockage. The sudden drop in the output of photovoltaic power plants. The first round of changes is large, but the change is slow; the second type of change is unpredictable and sudden, and in severe cases, the output is reduced from full to less than 30% of the rated value within 1~2s. After the peak period of photovoltaic output, in the process of smooth day and night alternation, the fluctuation of the output of the photovoltaic power station is the target to control the discharge of the energy storage system, discharge to the lower limit of the SOE working range of the battery energy storage system, and if it has entered the night, the output of the photovoltaic power station is reduced. By 0, the SOE of the energy storage system is still greater than 0.2, and the energy storage system is controlled to discharge at a constant power of rated power to SOE to 0.2, and then the energy storage system is controlled to stop working.
Working mode three: peak clipping + transfer
During the peak output period of the PV power plant, the peak energy is used as the application target to control the charging of the battery energy storage system. The output period of the photovoltaic power station is 8:30~18:30, and the late peak of the load appears between 18:00~22:00. During this period, the photovoltaic power station has basically no output, which can be assisted by controlling the discharge of the battery energy storage system. System peaking, in order to reduce the number of operation of the energy storage system and simplify the operation of the battery energy storage system, control the battery energy storage system to discharge at a constant power, discharge the lower limit of the SOE working range of the battery energy storage system, and then stop the energy storage system jobs.