Solutions and principles of energy storage systems on the generation sideenergy storage systems
The current normal operation of the power system must first face an engineering problem: to realize the real-time dynamic balance between power consumption and power supply. If consumption continues to be greater than the supply, it will form a power supply shortage, resulting in some customer blackouts; if the supply continues to be greater than the consumption, it will be manifested in the frequency exceeds the standard, affecting the quality of power, and ultimately affecting the normal use of the customer.
The principle is shown below:
The grid is located at the core of the power system and is responsible for maintaining the dynamic balance between consumption and supply. Adjusting the real-time power generation supply from the power source becomes critical, as power cannot be stored and deviations between consumption and forecasts need to be adjusted in real time. Traditional power sources work smoothly with the grid, but new energy power plants are constrained by natural conditions, and their volatility and intermittency pose challenges that require good controllability of the power source.
New energy development will force the grid to adjust the scheduling mode, gradually oriented to new energy direct scheduling. Generation side energy storage from the use of the main two categories: Auxiliary thermal power dynamic operation. It can reduce the cost of equipment maintenance and replacement, improve the efficiency of thermal power units, and thus reduce carbon emissions. Realize new energy-friendly grid connection.
Wind and photovoltaic power generation is affected by seasonal and meteorological factors, and has a large intermittency and randomness, through the configuration of the energy storage system, it can improve the renewable energy-friendly grid connection and promote the development and utilization of renewable energy.
From the level of application scenarios, over the past 10 years, the cumulative installed proportion of new energy storage on the power generation side has ranged from 21.2% to 47.6%, of which the installed proportion of new energy storage on the power supply side is the highest at 47.6% in 2020, and slightly decreases to 44.7% in 2021.
From the level of technology distribution, as of the end of 2021, the proportion of lithium-ion batteries in power generation side energy storage is 97.5%, followed by 1.4% of liquid current batteries, 1.0% of lead-acid batteries, supercapacitors, and flywheels, both of which account for 0.1%.
An expedient solution for the coexistence of power systems and new energy power sources：
In response to this dilemma, a solution is proposed: as long as the total power supply (new energy power generation + traditional power generation) is equal to the total power demand, the stability of the power system can be maintained. If the supply of new energy power is insufficient, the traditional power supply will be dispatched. Specific operational steps are: first predict the future electricity demand; then predict the overall future supply of new energy power supply, the difference between the supply and demand is the future supply of traditional power generation.
The traditional power supply is then broken down into each traditional power station, which forms the power generation plan of each traditional power station and the overall scheduling plan of the power grid. If the actual operation deviates from the plan, relying on the advantage of fast and accurate response of traditional power supply to the grid scheduling instructions, the grid adjusts the generation supply of traditional power supply in real time to realize the balance of supply and demand. Grid scheduling through this way of thinking, although not fundamentally solve the contradiction with the new energy power supply, but the same new energy power supply into the power system effectively.
The two prerequisites that constitute the scheme of rights and interests are changing rapidly. The grid will effectively integrate new energy power into the power system, traditional power (thermal power, hydropower) plays an important role. Implicit in this is an important assumption - the ability of traditional power sources to act as stabilizers.
When the proportion of traditional power supply is above 70%, of course, there is no problem, but as the proportion of new energy increases, when the proportion of traditional power supply is lower than a certain threshold (e.g., 50%), whether the grid still has enough traditional power resources to achieve a real-time balance of supply and demand in the power system?
This is a question that deserves attention. There are two prerequisites for the grid to realize a real-time balance of power supply and demand by dispatching traditional power supply: The new energy power supply installed share and power generation share are very small, and the impact on the power grid is limited; New energy power supply power generation cost is high and already needs government subsidies, and then additional power supply can be controlled requirements, the cost is even higher, the human energy transition will be greatly affected.
Now these two preconditions are rapidly changing:
1. the proportion of installed new energy power sources and the proportion of power generation are moving from incremental replacement to stock replacement. At the end of 2018, the sum of installed wind power and photovoltaic power sources accounted for 18.7% of all power source installations, and their overall power generation share amounted to 8.8%.
The grid wants to achieve a real-time balance of power supply and demand by dispatching traditional power sources, which is becoming more and more difficult as the proportion of traditional power sources becomes smaller and smaller.
2. New energy power generation costs are rapidly declining, new energy power supply compared to traditional power supply gradually formed cost advantage, new energy will gradually have the ability to bear the cost of "power control".
With the rapid change of these two preconditions, the grid scheduling mode of work will gradually change, and the new energy direct scheduling sooner or later will be put on the agenda. From the perspective of the power system as a whole, new energy will sooner or later become the grid that can be dispatched to power.
Energy storage on the power generation side will be the standard of a new energy power station, AEAUTO is committed to providing energy storage system solutions, if you want to know please contact us.
