As a clean energy source, the role is rather awkward

According to the "Research on the Flexible Operation Policy of Coal power Units" released by China Electric Union in December 2019, the proportion of flexible power supplies in Europe and the United States is generally high, with Spain, Germany and the United States accounting for 34%, 18% and 49% respectively. In China's new energy rich "three North" area, wind power, solar power installed capacity accounted for 72% of the country, 61%, but the flexible adjustment of power supply is less than 3%, adjustment capacity is inherently insufficient.

Before the energy storage technology breaks through the economic constraints and realizes large-scale commercial application, pumped storage, gas turbine units and coal power units with flexible transformation can all be used as flexible power sources of the power grid, and the three have advantages and disadvantages: pumped storage technology is mature and rapid response, but limited by site resources and construction period, far from hydrolyzed. The peak load balancing capacity of single-cycle gas turbine unit can reach 100%, and that of combined cycle unit can reach 70-100%, but they are faced with high gas price and gas source constraints. Coal power can improve the adjustment capacity to a certain extent through flexible transformation, but it needs to sacrifice the unit operating efficiency and increase coal consumption to lower the load. From the carbon emission results, the total carbon emission of the coal-fired unit after the flexibility transformation is still much higher than that of the gas-fired unit.

There is a more radical view that China's energy can be based on coal, over oil and gas directly transition to a zero-carbon system based on new energy. It sounds beautiful, but it's impractical. Under the rapid development of new energy, improving the flexibility of the power system has become a priority. Since energy storage technology is not yet commercially available on a large scale, a balanced power system requires the deployment of flexible technologies, including natural gas generation.

"I personally think this view is inappropriate (note: refers to the direct transition from coal-based over oil and gas to a zero-carbon system based on new energy). First, at present, China's power system does not have the ability to support new energy. The second is that this energy transition is too costly. To build a new power system, we should take the parallel road of energy structure adjustment and renewable energy development, that is, low carbon and zero carbon parallel." Tang Guangfu, academician of the Chinese Academy of Engineering and president of the Global Energy Internet Research Institute, recently said in an interview with the State Grid Magazine that the EU's clean energy and low-carbon development road has given us a lot of inspiration. We should adjust the energy mix by reducing the use of coal and increasing the use of oil and gas. Although China is highly dependent on foreign oil and gas, it is impossible to use natural gas in large quantities like Europe, but it should also moderately develop oil and gas resources, especially the development of natural gas power generation peak adjustment, in order to cooperate with the large-scale development and utilization of volatile and intermittent renewable energy. If we ignore the development of power grid peak load control resources, it will bring a huge and insurmountable technical gap to the construction of new power system.

Tang Guangfu cautioned that there is a misconception in the industry that as long as the energy storage problem is solved, everything will be solved. Of course, energy storage is to be vigorously developed. Energy storage can also meet some of the needs of peak cutting and valley filling, but energy storage can not completely replace flexible power supply. Before energy storage becomes a large-scale flexible power supply, it must rely on natural gas power generation or coal power with flexible transformation as a flexible power supply. The reason why the transition in the United States and Europe is more successful is that there is a large number of natural gas power generation as a flexible power source for peak balancing.

From the practice of European countries, the process of coal withdrawal has accelerated as aggressive climate policies and high carbon prices squeeze the profit margins of coal power plants. At the same time as the annual decline in coal power generation, renewable energy generation is increasing, and natural gas power generation as a flexible power source is also gradually rising.

"It is impossible to give up natural gas transition energy as a ferry car and want to directly board the new energy + energy storage bridge." Zhang Haicheng, chairman of Huizhou Deep Energy Fengda Power Co., LTD., said that the more renewable energy on the horse, backup power and flexibility measures should also grow at the same time, which is obviously insufficient. He told the surging news that under the existing technology path, on the way to the peak of carbon to balance the relationship between the expansion of energy demand brought by economic growth and emission reduction, there are not many options, and gas electricity as a flexible power supply and peak load unit is the most realistic choice.