Problems with power supply structure and grid structure

Problems with power supply structure and grid structure

Power structure problem

Most of the new energy power generation technologies have resource instability, that is, output instability, requiring conventional thermal power and hydropower (currently China stipulates that nuclear power does not participate in peak shaving) for peak shaving, thereby reducing the impact on the grid. However, in the primary energy structure of China’s electric power, hydropower accounts for about 20%, coal power accounts for more than 70%, and there are few other nuclear power, photovoltaic, wind power, pumped storage and gas power plants, which together account for less than 10%, resulting in the contradiction of power structure (base, waist and peak load power), that is, the power grid is seriously short of peak regulation power supply. At the same time, since nearly 100 million kilowatts of small thermal power originally served as the main peak load regulation has been shut down year by year, without supplementary peak load power supply, peak regulation often uses the deep pressure output of thermal power units or shutdown of some thermal power units, resulting in power shortage and energy waste. Even so, the current adjustable peak rate of water and thermal power only accounts for 20% of the total power source, which is far from meeting the 40% to 50% peak-to-valley adjustment requirements of the power grid. The promotion of new energy power generation technologies in China is facing tremendous peak-shaving pressure, and even “wind abandonment” has occurred.

On the other hand, the economics of thermal power and hydropower are currently better than wind power and photovoltaic power generation. In the current state of the power supply structure dominated by thermal power and hydropower, there is insufficient urgency to develop new energy power generation technology, which also restricts the rapid promotion and application of new energy power generation technology.

Grid structure problem

The unified whole of connected power generation and power consumption composed of power transmission, transformation, distribution equipment and corresponding auxiliary systems is called a power grid. At present, China has formed six inter-provincial large-scale regional power grids, namely, Northeast Power Grid, North China Power Grid, Central China Power Grid, East China Power Grid, Northwest Power Grid, and Southern Power Grid, which are managed by the two major groups (among them, Northeast Power Grid, North China Power Grid, Central China Power Grid, East China Power Grid, Northwest Power Grid are owned by State Grid Corporation of China, and China Southern Power Grid is owned by China Southern Power Grid Corporation).

At present, the popularization and application of new energy power generation technology is restricted by the structure of the power grid. This is mainly manifested in two aspects:

(1) The development of new energy power generation lacks a unified plan, and the construction of supporting power grids is difficult. At present, when developing wind power, photovoltaic and other new energy power generation technologies, governments in various parts of China mainly determine the development scale and construction time sequence based on local resource conditions, resulting in local plans that are generally larger than national plans. In addition, the development of new energy power generation projects is prone to disorder, especially in the field of wind power, where the dismantling phenomenon is more serious, and the construction layout and scale are more random. In addition, the approval and construction cycle of power grid projects is much longer than the construction cycle of wind farms and photovoltaic power plants, and it is difficult to achieve overall planning and coordinated development of wind power, photovoltaic power generation and power grids. The construction speed of new energy power generation projects is more prominent than that of power grid construction projects. This causes the contradiction that power generation cannot be connected to the Internet in time.

(2) The construction of China’s power grid lags behind the construction of power sources. In particular, the interconnection scale of the cross-regional power grid is insufficient, which is not conducive to the wider consumption of wind power and photovoltaic power generation. For a long time, China’s power development has focused on regional balance in different provinces and regions, and the interconnection of power grids between provinces is limited and the ability to adjust each other is insufficient. Due to the distribution characteristics of China’s wind and solar resources, the development of wind and photovoltaic power generation is mainly concentrated in the “Three Norths” area. Constrained by the local power load level and the scale of the system, the local consumption capacity of these new energy power is insufficient, resulting in the phenomenon of power consumption.