In Sun Xiaoqiang's view, solar thermal power generation can help solve the problem of power supply balance and power system safety in high-proportion renewable energy systems. He said that at present, the proportion of thermal power installed capacity in the grid is still relatively high, and the installed capacity of solar thermal power generation is small. Its characteristics have not yet appeared. However, in the future, as thermal power gradually withdraws, the "friendliness" of solar thermal power generation to the power system will Gradually highlight.
Ensuring the safe and stable operation of the new power system
Question: From the perspective of replacing thermal power, what role will solar thermal power generation play in ensuring the supply of electricity and implementing the national energy security strategy?
Answer: With the implementation of the national "dual-carbon" strategy, my country's thermal power construction space will be further compressed, and new energy installed capacity will increase rapidly, but its volatility makes it more difficult to guarantee electricity and electricity at different time scales in the power system, especially under extreme climatic conditions. It’s even more difficult to supply under.
With the addition of emergency gas-fired boilers, the output characteristics of solar thermal power plants are basically the same as coal-fired thermal power, stable and controllable, so as to realize full-capacity replacement of coal-fired thermal power installed capacity and ensure that most of the power generation is still renewable energy. better.
This is of great significance for getting rid of my country's high dependence on foreign oil and gas, ensuring national energy security, for quickly entering low-carbon energy from high-carbon energy, and achieving high-quality carbon peak goals.
Question: How to treat the peak regulation performance of solar thermal power generation?
Answer: As the installed capacity of new energy sources increases, its power fluctuations will further increase. In 2019, the maximum daily power fluctuation of new energy in the operation area of State Grid Corporation of China reached 107 million kilowatts, accounting for 31% of its installed capacity.
According to research by relevant institutions, it is estimated that the maximum daily power fluctuation of new energy across the country will exceed 1.6 billion kilowatts in 2060, exceeding the total installed capacity of conventional power sources such as thermal power, hydropower, and nuclear power that year. It is difficult to cope with the daily power fluctuations of new energy through conventional power regulation alone. , New energy consumption is facing huge challenges.
In the future, the scale of my country's new energy development will continue to expand, but the proportion of flexible power sources is low, and the power system's peak regulation capacity is seriously insufficient. The solar thermal power station has its own energy storage function, which can start and stop peak shaving like gas power. The minimum output of continuous power generation can be reduced to 20%, which is better than 40% of coal power; the regulation rate reaches the rated output (3%). ~4%)/min, which is approximately twice that of conventional coal-fired power generating units; the start-up time of steam turbines is only 20 to 60 minutes, which is only 1/3 to 1/4 of conventional coal-fired power generating units.
As a new energy with its own peak shaving, it has excellent regulation performance, and can fully complement the operation of photovoltaic and wind power to realize "regulate new energy with new energy" and "use new energy to promote new energy consumption".
Question: What is the significance of solar thermal power generation in implementing the national energy transition strategy?
Answer: Under the guidance of the "dual carbon" goal, my country will inevitably form a power system with a high proportion of new energy electricity. According to relevant forecasts, more than 55% of my country's electricity will come from new energy power generation in 2060.
The solar thermal power station itself is a new energy power source. In the process of energy transition, by optimizing the development structure of new energy, a certain proportion of solar thermal power stations can be built in the installed solar power generation capacity, which can not only reduce the configuration scale of conventional regulated power sources, but also effectively increase Proportion of renewable power generation, increase the proportion of renewable energy power consumption, and promote the development of green transformation of the energy structure.
Question: What are the main effects of solar thermal power generation on the safety of the power system?
Answer: For the safety of the power system, solar thermal power generation can solve three key problems: frequency safety, voltage safety, and power angle stability.
In terms of frequency safety, solar thermal power generation has rotational inertia and excellent frequency modulation performance, which can ensure the frequency stability of the AC power grid. Unlike photovoltaic and wind power, which are mostly power electronic components, the grid-connected components of solar thermal power plants are conventional synchronous units, which can provide rotational inertia for the system. At the same time, because it has no coal-fired boiler, its heat exchanger has high efficiency and can participate in the primary frequency regulation and Secondary frequency modulation has a performance that exceeds that of thermal power units, can quickly respond to grid load fluctuations, and maintain grid frequency stability.
In terms of voltage safety, solar thermal power generation, as a voltage support power source, can effectively suppress the transient overvoltage of new energy sources. The solar thermal power station is a traditional generator set that generates new energy. While generating active power like photovoltaic and wind power, it can also adjust the reactive output according to the voltage regulation needs of the system. At the same time, it can be used as a synchronous generator power supply to provide short-circuit capacity for the system. With voltage support capability, it can effectively suppress the transient overvoltage of new energy sources.
In terms of power angle stability, solar thermal power generation as a synchronous generator power source can improve the power angle stability of the AC power grid. The solar thermal power station integrates new energy sources and traditional steam turbine generators. It has obvious advantages as a synchronous generator power source. Because it does not have the combustion link of conventional thermal power boilers, the valve is easy to shut down and open, and the adjustment speed is faster. It can quickly respond to the emergence of the system. Large and small disturbances are of great significance for maintaining the stability of the power angle of the new power system.
The positioning of solar thermal power generation needs to be rediscovered
Question: From the perspective of the power grid, what are your expectations for the development of solar thermal power generation in the future?
Answer: First, the cost is further reduced. Affected by many factors such as technology, financing and electricity price policies, the construction and power generation costs of solar thermal power stations are still high. In the past 10 years, the cost of photovoltaic and wind power generation has dropped rapidly, and it has basically been able to achieve parity on the Internet. The cost of energy storage batteries represented by lithium-ion is also rapidly decreasing, and distributed adjustment cameras are needed to solve the transient overvoltage problem of new energy sources. Born.
Therefore, the development of solar thermal power plants is also facing competition with the route of "new energy + energy storage + adjustment camera", and the cost of solar thermal power generation needs to be rapidly reduced.
Second, the positioning of solar thermal power generation needs to be rediscovered. Under the “dual-carbon” goal, the consumption of new energy requires systematic thinking. As a thermal storage type peak shaving power source, solar thermal power generation should be designed from a global perspective at the beginning of the design, with the goal of maximizing the consumption of new energy in the system, and rational configuration Light collection system and heat storage system;
At the same time, in the future, the issue of power security for new power systems based on new energy is more important. As a stable supporting power source, CSP stations can replace conventional thermal power with full capacity by optimizing the configuration of emergency gas boilers to ensure reliable power supply under extreme weather conditions.
The third is that the performance of CSP stations needs to be optimized. At present, there are not many CSP stations that have been put into operation, and there has not been a practice of fully participating in grid peak shaving. The performance of CSP stations needs to be further verified. It is necessary to combine the operation requirements of grid peaking, frequency, and voltage regulation to rationally optimize CSP Station technical parameters to support the safe and stable operation of the new power system after large-scale development.
Fourth, the demonstration significance of "Integrated Photovoltaic and Thermal Development" is obvious. As photovoltaic technology continues to progress and costs continue to fall, the grid-connected power price for photovoltaics in Northwest China will be further reduced. Therefore, the integrated development of photovoltaic and solar thermal power generation aggregates low-cost photovoltaics and CSP stations that can perfectly replace thermal power. It has certain technical and economic advantages. Under the background of "dual carbon", it is important to promote the high-quality development of new energy. Positive demonstration significance.
At present, we are studying the supporting effect of CSP stations on the system, and strive to consider the development trend of the cost of various technical routes from the perspective of the overall national economy, through the use of solar thermal and new energy + electrochemical energy storage + adjustment camera, new energy + The technical and economic comparison of multiple schemes such as pumped storage, comprehensively sort out the comparative advantages of CSP in the whole process of power and electricity balance and the full function of grid operation, and provide a reference for the development of new energy in my country and the safe operation of the grid.