Yang Panfeng: Introduction to the Multi-energy Complementary Project in Qinghai Province

China Energy Storage Network News : From May 19th to 21st, the "8th China International Energy Storage Conference" was grandly held in Shenzhen. More than 1,500 representatives from government agencies, research institutes, industry organizations, power companies, new energy project units, system integrators and other countries and regions from China, the United States, Germany, the United Kingdom, Canada, Spain, Japan, South Korea, Australia and other countries and regions attended the conference.

Yang Panfeng, deputy chief engineer of Northwest Electric Power Design Institute Co., Ltd. of China Electric Power Engineering Consulting Group, delivered a wonderful speech entitled "Introduction to Multi-energy Complementary Project in Qinghai Province" at the "Energy Internet and Multi-energy Complementarity Special Session".

The speech is as follows:

Yang Panfeng : Good afternoon, everyone! I would like to share two projects with you. I have been engaged in the planning and design of power systems. My main work experience is in power system planning, such as power grid planning. In recent years, we have participated in the preparation of the "13th Five-Year Plan" power planning research in Shaanxi, Gansu, Qinghai, and Xinjiang in the northwest region. Including some power grid planning research. My explanation is mainly from the perspective of the power grid, how to achieve multi-energy complementarity. I will mainly share two projects.

There are two main contents. One is the large-scale multi-energy complementarity, the multi-energy complementarity of Qinghai Province, and the other is the multi-energy complementarity of Haixi Luneng. It mainly introduces our design considerations for these two projects.

The situation in Qinghai Province, as of the end of 2017, the situation of Qinghai power grid, we can see that Qinghai's total installed capacity is 25 million, hydropower installed capacity is 11.91 million, thermal power is 3.99 million, and renewable energy is 9.53 million. This figure is the data in 2016. In fact, you can calculate that in the Qinghai power grid, the proportion of thermal power in 2017 was only a little over 15%. It can be seen that more than 80% of Qinghai's installed capacity is renewable energy installed capacity.

Qinghai Province will develop two large clean energy bases in the long term, one is Hainan Clean Energy Base, and the other is Haixi Prefecture Clean Energy Base. Haixi Prefecture is characterized by particularly good light resources and vast desertified land resources, which are very suitable for the development of solar thermal and photovoltaic. In addition to the hydropower in the upper reaches of the Yellow River, Hainan Prefecture also has very good light conditions. The long-term development scale of these two bases is 30 to 40 million, which is a large amount. Therefore, the Qinghai power grid is a power grid with a high proportion of renewable energy. Conduct multi-energy complementarity research in the whole province of Qinghai. This is in the national "13th Five-Year Plan" energy plan, and it is also proposed in the national "13th Five-Year Plan" energy plan. It proposes that Qinghai, Gansu, Yunnan, and Guizhou use the combined advantages of wind, solar, hydropower, coal, and natural gas resources in large energy bases to establish supporting power dispatching, market transactions, and price mechanisms, carry out wind, light, water, and fire storage multi-energy complementarity, integrated operation, improve the stability of the power system, and improve the capacity and comprehensive benefits of wind power, photovoltaics, and intermittent renewable energy in the power system. This is a large province-wide multi-energy complementarity. The overall design idea for the multi-energy complementarity of Qinghai Province is to utilize the power sources of the hydropower group in the upper reaches of the Yellow River, solar thermal and pumped storage solar thermal energy storage. In the large power system, hydropower and pumped storage are more mature. Under the premise of meeting the economic efficiency of power generation, through optimized scheduling and complementary operation of photovoltaic and wind power, the imbalance of power and output fluctuations in different time scales, such as years, months and days, can be smoothed to meet the requirements of safe and reliable power supply and DC power transmission.

The main steps of our research are as follows: 1. Solve the imbalance of seasonal power in the large power grid. New energy installed capacity accounts for a large proportion. For example, photovoltaic power generally generates more power in spring and autumn, and generally consumes less power in spring and autumn. There is a seasonal imbalance in itself, which is mainly solved by hydropower cross-regulation. Then a long-term power purchase agreement with the surrounding provincial grid is established to solve it. 2. Solve the imbalance of daytime power. A large amount of photovoltaic and wind power, it changes with the weather, such as sunny and cloudy days, more power generation on sunny days, less power generation on cloudy days. This imbalance must be solved by energy storage. It is unrealistic to store energy through batteries for such a long time scale. The main consideration is the conditions of hydropower and pumping. 3. Photovoltaic power mainly generates power during the day, not at other times. In this way, it is also necessary to reasonably configure the power supply of energy storage and the power supply of frequency modulation every day. By optimizing the working position of the daily load curve of various power sources every day. 4. After configuration, the production simulation calculation is carried out for 8760 hours throughout the year, and the power demand of Qinghai for 8760 hours is met by means of hydropower, solar thermal, pumping and storage and inter-provincial coordination. 5. Optimize the plan, mainly by adjusting the power supply structure and optimizing the energy storage capacity.

The multi-energy complement optimization software is used to solve the problem. The main thing is to determine the power of the load and DC, the characteristics of water energy and the output characteristics of new energy, and the long-term trading curve of the interconnection line. With the goal of minimizing coal consumption and maximizing the acceptance of water energy and new energy, the startup plan and operation mode of the unit are arranged to achieve production simulation calculation within a given period and calculate a series of indicators. To evaluate the large multi-energy complement, the system is mainly evaluated from four aspects. For the power supply of the load, whether it can guarantee the power supply of the load after this multi-energy complementation, the reliability indicator is mainly used here. The utilization of new energy in the system and whether the new energy has been fully utilized are listed here through the indicators of abandoned electricity. The abandoned electricity includes hydropower, photovoltaic, solar thermal, and wind power. It is possible to abandon electricity directly, or it is possible that after peak regulation, the efficiency of solar thermal operation is low, which will be less than the original power generation. The third is the economic efficiency of operation, the economic indicators, and the economic indicators here write the economic efficiency of operation. When we design, the construction economy of power configuration is considered together. The main thing here is to see whether the utilization hours of thermal power are reasonable, and then the various regulating energy storage regulation losses. Another consideration is that through so many multi-energy complementarities, there are also transactions of electricity and power with other regions and provinces. We cannot rely too much on transactions. Therefore, in Qinghai's multi-energy complementarity, we mainly rely on long-term transactions, not short-term transactions. This means that the system is considered to be more reliable.

The final conclusion of the study is that the direct current project from Qinghai to Henan has now started, and it may be started this year. This is a direct current project that transmits 10 million kilowatts of electricity, and Qinghai transmits electricity to Henan. This project relies on the Qinghai power grid. The load of the Qinghai power grid itself is only more than 10 million kilowatts, plus the direct current transmission is 10 million kilowatts. For such a system, my installed capacity is about 16 million kilowatts of hydropower, and the proportion of thermal power is very small, only 5.1 million kilowatts. New energy is photovoltaic, solar thermal, and wind power with more than 20 million kilowatts. Such a system, through the comprehensive operation of this system, the above-mentioned four indicators must be achieved. The effect of multi-energy complementarity after research, non-complementarity is the general operation of conventional power systems. Conventional power systems generally consider the peak-shaving effect of thermal power and hydropower during the day. Basic complementarity mainly considers the cross-day regulation of hydropower, and considers the use of solar thermal power stations, which basically have energy storage. Consider the use of this energy storage, and the solar thermal power station participates in peak regulation. It can be seen that they are not complementary. The conventional operation mode of the power system and the multi-energy complementary mode have significantly improved the reliability of the power system, including the improvement of the amount of power abandonment, that is, multi-energy complementarity. Further work is done from the perspective of optimization: with the surrounding provinces, Qinghai’s surrounding areas relative to Xinjiang, Gansu, and Shaanxi, there are some long-term trading curves. Based on the principle that both parties can benefit from each other, some long-term surrounding trading curves are formulated. In addition, the power structure is also adjusted. When power abandonment occurs, the power structure is adjusted. Including the DC curve, combined with the power supply situation at the sending end and the load situation at the receiving end, the DC curve is optimized and adjusted.