Main content:
Grid connection in the power industry refers to the connection of the generator set transmission line to the transmission grid, and in the heating industry refers to the merger of two heating pipe networks.
Behind the rapid expansion of the market, all aspects cannot keep up with development, resulting in energy not being fully converted into energy.
1. Severe grid-connected latency problems
According to the scale and installation form of photovoltaic power generation system, it is divided into centralized photovoltaic grid connection and distributed photovoltaic grid connection.
● Centralized photovoltaic grid-connected
It generally refers to large-scale photovoltaic power stations built in large areas of deserts, wastelands or water surfaces. The electrical energy is directly integrated into the high-voltage transmission system, which is evenly distributed to supply power to the user.
The power exchange between grid-connected centralized photovoltaic and high-voltage transmission systems is unidirectional. Usually, large-scale photovoltaic power stations are located in remote locations and require long-distance transmission lines to send power into the grid, which will cause some line losses.
● Distributed photovoltaic grid-connected
In general, photovoltaic power generation facilities are built near the user site, and the operation mode is spontaneous self-consumption on the user side, surplus electricity is on the Internet, and the balance adjustment of the power distribution system is featured. The most widely used distributed pv system.
It refers to the use of solar photovoltaic panels on the roof or building façade, and the generated electrical energy is directly connected to the user load at the inlet switch of the user's distribution box, or directly connected to the low-voltage bus bar of the substation.
When the photovoltaic power generation capacity and the total load capacity of the transformer load end are not equal, it can be adjusted through the power grid, and the power exchange between the photovoltaic power generation system and the power grid can be bidirectional.
However, distributed photovoltaic power generated by the home energy storage can be implemented with the approval of the relevant departments to achieve surplus power on the grid. The United States is one of the most important markets for the global energy storage industry.
Since 2020, with the rapid rise of photovoltaic and wind power installations, the instability of the power system has promoted a significant increase in the proportion of clean energy distribution and storage, and driven by multiple factors such as energy storage policies and technologies, the installed capacity of energy storage in the US has grown rapidly.
However, behind the rapid growth of energy storage facilities, the U.S. energy storage market has a serious problem with grid connection delays. Affected by the cumbersome grid-connected process, the average queue time for clean energy in the United States is more than 2 years.
2. The main process of grid-connected research
The U.S. transmission and distribution network is seriously aging, and grid system operators or utility companies require new energy projects, including energy storage, to conduct a series of grid-connected impact studies before they are connected to the grid.
● Feasibility
Determine whether a project will cause power failures when connected to the grid and assess whether grid upgrades are needed to avoid related problems.
● Systems impact
More detailed information from developers and a deeper assessment of the project's impact on the grid are needed, with the potential for project design changes during the process.
● Facility
Estimate in more detail the cost of equipment, engineering, and facility modifications required to bring your project online.
3. The main reason for the lack of energy supply
The main reasons for the delay in grid connection in the market can be summarized as the cumbersome grid connection research process and the high cost of grid transformation.
● Cumbersome grid connection research process
After each study is completed and approved by management, the project can move on to the next stage. However, if other projects in the queue with large installations decide to leave the queue, the project may need to be revisited. This cumbersome process greatly delays the development of energy storage projects.
In addition, some people believe that in the research process, grid managers lack an understanding of energy storage technology and functions. It pays too much attention to the negative impact of energy storage systems on the grid system, and ignores the help of energy storage systems to the grid system in peak shaving and frequency regulation, which delays the development progress of energy storage systems.
Upon completion, the project is considered economical or not. If a decision is made to connect to the grid, an agreement with management is required, which contains a plan to upgrade the grid facilities and is not actually completed until the facilities are completed.
● High grid retrofit costs
The overall power grid system in the US is relatively old, and with the continuous rise of new energy access, some power grids are overwhelmed. As a result, there are additional costs to renovate the power plant, such as grid and substation upgrades.
Due to the high cost of grid transformation and the relatively low cost of queuing, some developers in the US energy storage market have also applied for the same project in different regional power grids, and then cancelled the queue after obtaining information on the cost of grid transformation in each region, which further aggravates the delay problem of other projects to a certain extent.
4. The development status of the grid-connected problem
If the core problem is not solved, the grid connection problem will still exist in the short term. Cumbersome procedures and confusing regulations in various places have severely affected the development of renewable energy in the region. Implement centralized grid-connected studies.
Conduct unified research on multiple grid-connected projects to be built, rather than studying each grid-connected project separately, improving grid-connected efficiency and reducing latency costs. Speed up grid-connected queue processing and punish grid operators who fail to complete grid-connected studies in a timely manner.
Grid operators are required to allow multiple generation facilities, including energy storage facilities, to be built at shared sites behind a single grid-connected point. and share a single grid-connected request. Grid operators are required to allow customers to add new items to existing grid connection requests in certain circumstances.
Although the process of connecting renewable energy to the grid has been greatly simplified, it still does not solve the most critical problem of grid transformation cost allocation. The current aging power grid in the United States cannot accommodate large-scale clean energy access. And its high renovation costs involve benefits.
5. Conclusion
The measures do not fundamentally solve the problem of grid integration in the United States. The proposed centralized grid-connected research method has been applied in some regions before, but has had little effect.
In the future, the problem of grid connection delays will still hinder the development of large-scale energy storage markets, and at the same time, it will affect the demand for energy storage lithium batteries to a certain extent in the short term.
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