Title: During the dry season, the supply and demand of electricity in some provinces in the southwest is tight, which has aroused many concerns - the "water shortage" in major hydropower provinces has a solution

Load reduction ratio of about 40% - Recently, many electrolytic aluminum enterprises in Yunnan Province received a notice to reduce the power load. A local aluminum enterprise revealed that this is the third time since September 2022 that Yunnan Province has required the reduction of electricity load.

Behind the reduction is the tight power supply and demand situation in Yunnan, a major province of water and electricity. China is moving towards the goal of "dual carbon" in an orderly manner, and renewable energy sources such as wind, light and water are placed on high hopes. However, renewable energy is inherently volatile and unstable. In the past two years, Yunnan, Sichuan and other major hydropower provinces in the southwest will face the problem of "water shortage" during the dry season, and power supply and demand are obviously tight. How to resolve this contradiction has aroused the attention of all parties.

Water is scarce and electricity supply and demand are tight

Mentioning the power rationing of the electrolytic aluminum industry in Yunnan Province, it can be started from September last year.

The relevant person of the local electrolytic aluminum enterprise reflected that since September 2022, the enterprise has received three notices of the power load reduction in Yunnan Province. The first time requires a preliminary reduction of about 10% of the electricity load, the second reduction of the electricity load is 15%-30%, and the third time is in the near future, requiring a reduction of about 40% of the electricity load.

Why implement load management measures for some high energy consuming enterprises? Increasing demand for electricity and insufficient water supply are two of the main reasons.

Yang Kun, executive vice chairman of the China Electricity Council, told this reporter that in recent years, the load of aluminum and silicon photovoltaic industry in Yunnan Province has grown rapidly, and the demand for electricity has risen more than expected, which has become one of the factors of tight power supply and demand in the province. On the other hand, during the dry season of this year, drought weather occurred in 90% of Yunnan province, resulting in severe hydropower output limitation and serious shortage of hydropower station capacity.

As of the end of last year, the province's installed power generation capacity was about 111 million kilowatts, of which hydropower installed capacity was 81.12 million kilowatts, accounting for more than 70%. Therefore, hydropower output is the key to the balance of power supply and demand in the province." Yang Kun said.

Like wind, light and other renewable energy sources, hydropower has the characteristics of "relying on the sky to eat". Zeng Ming, director of the Energy Internet Research Center of North China Electric Power University, told our reporter that generally speaking, the dry period is from October to April of the following year. For Yunnan Province and other provinces with large hydropower, there are obvious differences in power supply between wet season and dry season. In particular, Yunnan, Sichuan and other major hydropower provinces also shoulder the responsibility of "west power transmission to the east", which should not only ensure the power consumption in the province, but also take into account the power transmission between the provinces. When the water is dry, the power supply is obviously insufficient, and it needs to be adjusted by other means. Among them, guiding high-energy-consuming enterprises to use electricity in an orderly manner and use electricity at different peaks is one of the important adjustment means.

Data released by the Yunnan Supervision Office of the National Energy Administration show that in recent years, the power supply guarantee situation in Yunnan Province is severe and complicated due to the adverse factors such as the substantial growth of provincial electricity demand and the abnormal drying of water in major river basins. It is estimated that the electricity load in Yunnan Province will increase by 7% this year, and the electricity consumption will increase by 13.3%, and the annual electricity growth in the next three years will be more than 20 billion KWH. In order to fully protect people's energy, prevent large-scale power cuts and ensure stable economic and social development, Yunnan Province began to carry out load management for more than 300 high-energy-consuming enterprises in the province since September last year. As of March 20 this year, load management has been implemented for 192 days, and the cumulative execution of 12.956 billion KWH of electricity.

Plan the "fire and water scenery" joint dispatch

In the past two years, not only Yunnan Province, not only the traditional dry season, but also the southwest hydropower province is generally facing a shortage of power supply and demand. How to resolve this contradiction? Experts believe that planning ahead is essential.

"Sichuan, Yunnan and other hydropower provinces, to fully take into account the power consumption in the province and 'west to east transmission' and other electricity demand." In order to ensure the stability of intra-provincial and inter-provincial power transmission, when signing the inter-provincial power transmission agreement, we should fully consider the factors such as the difference of incoming water during the abundant and low water periods, make overall planning in advance, and weigh the transmission demand of other eastern provinces while taking into account the guarantee of electricity in the province, and agree to it in the medium and long-term contract." "Zeng Ming said.

It is necessary to strengthen the judgment of the change of water and coal supply and electricity demand to alleviate the power shortage situation in the major hydropower provinces during dry season. Yang Kun believes that it is necessary to give full play to the role of annual regulation and multi-year regulation of the reservoir, rationally control the water level of the reservoir, clarify the pre-control target water level of the reservoir by month, and ensure the safety protection capacity of the power grid system while ensuring the power supply. "At the same time, it is necessary to strengthen the joint operation of 'water, fire and scenery', speed up the study of scientific and reasonable power production and supply structure under multiple boundary conditions such as extreme climate and transmission channel capacity, and make timely adjustments to fundamentally solve the hidden dangers of power gap during dry seasons in major hydropower provinces." Yang Kun said.

The shortage of power supply in large hydropower provinces also reminds the industry to strengthen the diversified supply of electric energy, especially the regulatory role of thermal power.

Yang Kun told reporters that for a long time, the development of coal power in Yunnan Province has been slow. At present, coal accounts for about 11.7% of Yunnan's installed power generation capacity, and the utilization hours of coal power units have been low for a long time, only 2,858 hours last year, far below the national average. When there is a large fluctuation in renewable energy power generation and a shortage of supply, coal power with strong controllability can not be supplied due to insufficient preparation, which will affect electricity consumption.

It is understood that the major hydropower provinces have made efforts in this regard. Among them, the Yunnan Provincial Development and Reform Commission issued the Implementation Plan for the Market-oriented Reform of coal-fired power generation in Yunnan Province (Trial) at the end of last year, requiring the establishment of a coal-fired power generation regulation capacity market. "The plan is conducive to improving the enthusiasm of market players to invest in the construction of new thermal power projects and the implementation of flexible transformation of coal power units, and will play a positive role in improving the absorption capacity of new energy and ensuring power supply." Yang Kun said, "Of course, the development of coal power needs to be arranged as far as possible in accordance with the idea of 'increasing machine and reducing quantity', under the premise of increasing thermal power installed capacity to meet the requirements of power balance, priority is given to the use of clean energy power generation, and the carbon emission intensity of power generation is reduced as a whole." In the use of coal power units, carbon dioxide capture, storage and utilization and other related technologies should be widely used to reduce environmental pollution and control carbon emissions as much as possible."

We will give full play to the role of a unified national electricity market

Electricity is a special commodity, both to ensure a stable supply, but also to reflect its time value. Experts pointed out that with the gradual formation and improvement of the national unified power market, such as the Southwest hydropower province faced with this kind of electricity supply and demand contradiction, is expected to be solved through market-oriented means.

"The power supply capacity is weak during the dry season, but the power supply still needs to be kept up, and at this time, the large power grid needs to be adjusted." This regulation usually consists of a variety of measures, such as various types of energy storage, charging at peak times and discharging at low times, to balance the power supply." Zeng Ming said, "Of course, these means should enter the electricity market, and the market supply and demand situation will determine the value of the corresponding adjustment capacity and the corresponding price." In addition, the electricity price mechanism can be used to encourage users to use off-peak electricity. Especially for high-energy-consuming enterprises such as electrolytic aluminum, using peak and valley electricity prices to guide off-peak power consumption is one of the ways to ensure a relatively stable supply of electricity."

The reporter learned that the National Development and Reform Commission previously issued the "Notice on Improving the policy of ladder electricity Price in the electrolytic aluminum industry", which improved the policy of ladder electricity price in the electrolytic aluminum industry from seven aspects, such as adjusting the ladder electricity price grade standard power consumption indicators and encouraging electrolytic aluminum enterprises to improve the level of clean energy utilization. The Notice on Further Improving the time-of-use Tariff Mechanism issued by the National Development and Reform Commission requires the improvement of the seasonal tariff mechanism. In places where the proportion of renewable energy such as hydropower is significant, overall consideration should be given to the multi-energy complementary factors of wind and water, and further establish and improve the mechanism of abundant and weak electricity prices. The floating proportion of electricity price is set reasonably according to the supply and demand situation of the system.

"Adjusting the electricity price mechanism has indeed played a role in guiding off-peak electricity consumption to a certain extent." The person in charge of an aluminum company in Southwest China told reporters, "If the electricity load is too large, it may face limited production and production reduction." We are also actively responding to off-peak power consumption in order to reduce production and operating costs and meet emission reduction targets."

While improving the electricity price mechanism, it is necessary to speed up the construction of a national unified electricity market, which is also an important means of orderly allocation of electricity and ensure stable supply. Experts pointed out that the national unified electricity market has broken down the barriers to inter-regional trade, helping to allocate electricity more quickly to meet electricity demand, in order to resist the instability of power supply caused by natural disasters.

"Taking Yunnan as an example, by participating in the southern regional power market and in the future participating in the national unified power market, resources can be optimized on a larger scale, so that Yunnan can get more power support from other provinces during periods of tight supply and demand, and better promote the consumption of renewable energy such as hydropower during periods of loose supply and demand." Yang Kun said, "Participation in the power market trading can also increase the income of Yunnan power enterprises in the auxiliary service market and alleviate the operating pressure of thermal power and other regulated power supplies." Therefore, continuing to deepen the power reform and accelerate the construction of the national unified power market will play a great role in resolving the similar phenomenon of electricity consumption in Yunnan Province, and it is of great significance."