What is the concept of new electric energy?

New energy power systems and their characteristics

With the development and utilization of new energy power such as wind power and solar power, the proportion of new energy power connected to the power grid is increasing. As we all know, the basic characteristic of electricity is that it is difficult to store on a large scale, and the production and consumption of electricity must be carried out simultaneously. Through unified dispatching and command, the power system enables power production to follow changes in load demand and ensures a real-time balance between supply and demand of electric energy. For traditional power systems, the power dispatch center issues dispatching instructions to the power generation units according to changes in user load demand. The power generation units execute Automatic Generation Control (AGC) dispatch instructions to change the power generation load to meet user load needs and maintain grid security. Stable and guaranteed power quality. When the dispatchable capacity on the power generation side is difficult to meet the demand on the load side and situations occur that may affect the security and stability of the power grid, the power dispatch center will take measures such as cutting off user loads to ensure the safe and stable operation of the power grid. For traditional thermal power, hydropower, nuclear power, and oil/gas power generation, power generation units generally have good dispatchability. The generating set can change the generated power within a certain capacity range according to the grid dispatch AGC instructions. Therefore, on the premise that the installed power generation capacity can meet the user's maximum load, the entire power system is adjustable and controllable. An important feature that distinguishes wind power and solar power from traditional power generation is its random fluctuation. Since the primary energy that generates electricity comes from the flow of natural air and the radiation of sunlight, it is not only unstorable, but is also affected by seasons, climate, time and space, and has strong random fluctuations and intermittent properties. Therefore, for certain installed capacity For a new energy power generation unit with a large capacity, its actual output first depends on the constraints of wind power and solar intensity at the current moment. When wind power and solar power are connected to the power grid on a large scale, the power system must achieve a balance between power supply and demand between the randomly fluctuating power generation side and the randomly fluctuating load side to maintain the security and stability of the power grid.

Another important feature of new energy power is its low energy density. For example: when the wind speed is 3m/s, its energy density is about 20W/m2. However, even at noon on a clear day, the energy density of solar energy projected vertically to the earth's surface is only about 1000W/m2. This makes new energy power generation The single machine capacity of the equipment cannot be too large. A large number of small-capacity generating units are connected to the power grid, resulting in an explosive growth trend in controlled power generation units in the power system. As of the end of 2012, my country's cumulative installed capacity of thermal power units was 819.17GW, and the total number of thermal power units with a single unit of 6MW and above was approximately 6,600 units. During the same period, the total installed capacity of wind turbines was only 75.324GW, but the number of installed units reached 53,764 units, exceeding that of thermal power units. 8 times the quantity. According to the expectation that my country's wind power installed capacity will reach 200~300GW in 2020, based on the current average single-machine installed capacity of wind power, the number of wind turbines that need to be integrated into the power grid will reach 140,000 to 210,000 units! With the large-scale development of new energy power and the increase in the proportion of new energy power in the power grid, the basic characteristics of the traditional power system have undergone significant changes, mainly reflected in the following aspects: randomness, controllability, security, Holistic and intelligent. This will in turn promote fundamental changes in the structural form, operation control methods, planning, construction, and management of the power system, which will gradually form a new generation of power system, that is, a new energy power system.