Safe and flexible, the basis for large-scale application of new energy

The volatility and intermittency of new energy generation require that the power system must be flexible. If the power system lacks flexibility, when the regulation capacity of the conventional power supply is insufficient to meet the changes in the net load of the system, in order to ensure the safe and stable operation of the power system, it is necessary to reduce the new energy output when the electricity demand is insufficient, or cut the load during the peak period of electricity consumption, corresponding to the situation of “abandoning wind and abandoning light” and “orderly electricity consumption” respectively. This will directly affect the consumption of new energy and restrict the development of new energy.

685-151509-001 Germany is one of the countries with the highest penetration rate of new energy. In 2010, the German curtailment rate was only 0.33%, but as the proportion of renewable energy generation approached 30%, the curtailment rate began to rise, and by 2016, the German curtailment rate had risen to 4.3%.

Source: Energy Research Institute, National Development and Reform Commission

A Quantitative Comparative Study on the Flexibility of Power Systems in Beijing-Tianjin-Hebei and Germany

In 2020, wind power + photovoltaic power generation in China will account for about 9.5%, wind abandonment rate of 3.5%, and light abandonment rate of 2%. With the increase of the proportion of new energy generation in China, the pressure of wind and light abandonment will continue 685-151509-001 to increase, and the demand for the flexibility of the power system will become more and more intense. Therefore, it is necessary to improve the security and flexibility of the power system in many aspects.

01

Expand the power supply scale

Among the existing technical means, the flexibility transformation of thermal power can greatly improve the system flexibility. The minimum stable output can be reduced to 20%-30% of the rated capacity through the technical transformation of thermoelectric decoupling and low-pressure combustion stabilization, and the input per kilowatt is only higher than the demand-side management. While improving system reliability, it can promote the large-scale consumption of renewable energy.

02

Increase storage capacity

685-151509-001 In the future power system with new energy as the main body, only relying on the flexible transformation of thermal power can not fully meet the flexibility needs. As a flexible power regulation resource, energy storage can improve and enhance the flexibility of power system. In the “oversupply” scenario, excess wind power and photovoltaic power can be stored; In the case of “short supply”, discharge can alleviate short-term power shortage.

Source: SolarPower Europe

Energy storage systems play an important role in different scenarios:

On the power side, the mode of new energy + energy storage and hydrogen production from renewable energy is conducive to calming the output fluctuation of new energy, thus promoting the consumption of centralized new energy connected to the grid;

Power grid side: Pumped storage + new energy storage can assist the 685-151509-001 power grid to achieve peak regulation and frequency modulation needs and improve stability;

Load side: Market mechanisms (such as time-of-use price, power spot trading, demand response, etc.) and distributed new energy can be used to improve the level of energy cleanliness, reduce electricity costs, and also help to ensure the reliability and continuity of load side power supply.