How can China's photovoltaic power generation and grid development be more coordinated?

Solar power is the main force for future power supply. Now, the country has put forward the idea of ​​multiple developments in energy cleanliness. The purpose is to allow nuclear power, wind power, and solar energy to co-ordinate the development, but from a longer-term perspective, solar power generation may be the ultimate, Leading power supply solution. From the perspective of global scope and energy development, due to safety issues, there is a certain degree of uncertainty about the prospects and status of nuclear power development. Individuals believe that nuclear power is only a transitional solution (it may take longer for the transition). It is not an ultimate technological solution, because foolproof nuclear power is difficult to achieve both theoretically and practically. The occurrence of many major accidents and security incidents is a superposition of many low-probability events, and is often out of the various plans and human expectations. Because of the alternative nature and selectivity, with the development of the world economy and the promotion of safe and environmentally-friendly concepts, people prefer to accept higher-priced renewable energy sources and do not want to suffer even one millionth or less. The security risks in Europe have already explained this.

From a scale point of view, the country’s installed target for solar power generation is relatively conservative, with only 5 million kilowatts in 2020, and later adjusted to 20 million kilowatts. The latest planning target may be 50 million kilowatts. I think that this figure is still conservative (it has not considered CSP). Since the pace of development of nuclear power will moderately slow, and it is necessary to complete the 15% non-fossil energy development target by 2020, it is definitely necessary to increase the scale of wind power and solar energy. Compared with the continued increase in the scale of wind power installation, the appropriate increase in photovoltaic power and heat The scale of power generation is more favorable and feasible for the development of the power system and the entire new energy industry.

Practically speaking, China's wind power grid integration and consumption are facing many difficulties. The outside world also has a lot of misunderstandings about power grid companies. The main reason is that it is subject to many objective conditions and physical conditions, not to solve problems, but to deal with a large number of Technical, planning and construction issues, system security issues. Relatively speaking, the photovoltaic power generation characteristics and the power load characteristics are in better agreement. The scale of a single power station is not as large as some current wind power bases, and the requirements for power grid access and transportation will be lower, and it will be able to achieve close proximity. . Therefore, it is more feasible to further increase the scale of photovoltaic power generation, accelerate the development of light and heat, and access the power grid relatively decentralized.

Judging from the structural layout, in addition to the development of photovoltaic power plants of 10,000 kilowatts and 100,000 kilowatts in the desert areas of the central and western Gobi, small-scale, micro-photovoltaic power plants should be established in remote mountainous areas and islands to actively develop rooftop photovoltaic systems in cities. These systems may not be large on a single scale, but promotion is very effective in promoting industrial development. The contribution to clean energy power is also very significant.

In addition, we should also pay special attention to economic issues, which are cost and price issues. In the long run, our company needs to focus more on technical R&D and innovation. However, based on reality and on the basis of national conditions, it is still necessary to highlight cost advantages, and the main purpose of our technological breakthrough is also to reduce costs. Because economy is the core factor that determines the size of a technology and industry's competitiveness. If your costs cannot be reduced to a relatively competitive and scalable application, what ideas and policies are difficult to help you achieve your goals? .

To solve the problem of photovoltaic power generation and grid coordination as soon as possible. What is coordinated development? In my opinion, coordinated development is the intersection of coordination and development. It is an evolutionary process from system to system, or from one element to another within the system, that is consistent, well coordinated, from low to high, and from simple to complex. It mainly emphasizes overall, comprehensive and balanced development. It does not unilaterally pursue the development speed of a single system, and focuses on the balanced development of multi-system or multi-elements in the overall goal.

According to the connotation of coordinated development, the key is to make the photovoltaic power generation and power grid development match in terms of speed, balance in scale, adapt technically, regulate in management, and support policy. Because, whether it is photovoltaic power generation or solar thermal power generation, from the point of view of the entire power system, it is a power source and it is an organic component. Therefore, it must consider its coordination with the power load, coordination with the planning and operation of the power grid, and Coordination of other power sources.

The coordinated development of photovoltaic power generation and power grids is mainly reflected in the three key links of transmission, transmission, and utilization. The power generation link is mainly the power prediction and operation control; the transmission link is mainly how to solve the power transmission problem of large-scale photovoltaic power stations; How to realize energy efficient energy storage and two-way interaction with users. Solving these problems can only avoid the detours of large-scale development of wind power.

The first experience in the coordinated development of photovoltaic power generation and power grids abroad is speed control. As a growing industry, solar power generation should be accelerated at this stage, but the increase in speed is not without boundaries. While strengthening policy incentives, we should maintain a balanced and orderly development and avoid problems such as ups and downs and the rapid increase in social costs brought about by explosive growth and difficulties in power consumption.

Although the development of photovoltaics in Germany has attracted worldwide attention, the continuous and rapid growth since 2006 has led to a series of problems. For example, terminal electricity prices have grown too fast, the distribution network has become increasingly constrained, and the demand for power grid upgrades has increased. Therefore, Germany recently cut its on-grid tariffs to curb overheated investment in the industry.

Second, it is balanced in scale. The ability of power systems to accept such volatile power sources, such as photovoltaic power generation, depends to a large extent on the flexibility of system operation. The flexibility of power system operation is mainly reflected in the proportion of flexible power available to the system, the power grid infrastructure and interconnection scale, and the demand side response capability. Therefore, the scale of photovoltaic power generation must be balanced with the system's flexible adjustment of resource size.

Again, it is technically adaptable. From the perspective of the development of photovoltaic power generation, the development of photovoltaic power generation must meet the requirements of the development of the power grid. It is to build a power grid-friendly photovoltaic power generation station, and to improve the adjustable and controllable photovoltaic power generation in an all-round way, and to meet the requirements of flexible grid dispatching and operation. Compared with conventional power plants, there are significant differences in the operating characteristics of solar photovoltaic power generation, which are mainly reflected in the intermittent and random nature of power generation output. Different from ordinary photovoltaic power plants, the grid-friendly photovoltaic power plant has control characteristics similar to those of traditional power sources. It can meet relevant technical standards and requirements in terms of active power control, reactive power control, and power quality.

Germany's "Renewable Energy Law" clearly stipulates that photovoltaic installations with an installed capacity of more than 100 kilowatts must be equipped with remote control devices. The grid operators can directly adjust their power generation output under grid overload or other safety constraints. The grid operator has the right to control the grid-connected photovoltaic power generation equipment with a capacity exceeding 100 kilowatts under certain conditions.

In large-scale centralized photovoltaic power plants, changes in irradiance will cause fluctuations in output, which will have a great impact on the peak-to-peak frequency regulation of the power grid and the safety and economic performance of the operation. Photovoltaic power generation forecasting is a response to this adverse effect. Important technical means. Research on photovoltaic power generation forecast has been carried out abroad. For example, the United States proposes photovoltaic power forecasting, which is divided into short-term forecasting and long-term forecasting. The short-term forecasting is 1 to 3 hours ago and 1 day ago, and the long-term forecasting is season and year. It is used for long-term purposes. For planning purposes, the Technical University of Denmark also carried out relevant research and proposed that the irradiance of the numerical weather forecast is used as input to predict the power generation of the photovoltaic power generation system.

Finally, it is a policy package. Under the current technology and economic conditions, it is still not fully capable of market competition. Therefore, the government needs to introduce incentive policies to promote the development of photovoltaic power generation, and provide investors with investment in photovoltaic power generation with necessary market protection and basic earnings expectations. The incentive policies adopted by countries mainly have the following forms:

The first is to implement a preferential Internet access policy. Countries generally require priority access to the PV under the premise of ensuring the safe and stable operation of the power grid. For example, according to German law, only in the special case of overloaded power grids that affect the safe and stable operation of the system, the power grid companies may not implement preferential acquisition of photovoltaics; the second is the introduction of on-grid tariffs with expected return on investment. The fixed on-grid price mechanism is a universally adopted policy in Europe and the United States and has been successfully applied in many countries. Germany has a long-term “fixed on-grid tariff”, with a clear starting price and declining rules year by year; Spain has set ceilings and minimums for subsidies to ensure that the project’s internal rate of return stays at around 7%; and thirdly, it implements a renewable energy quota system. Ensure that government planning goals are achieved. The renewable energy quota system is a government policy that mandates that renewable energy in the region must reach a certain percentage of power generation or consumption. By the end of 2010, Australia, Japan, India, and 36 U.S. federal states and other countries and regions have implemented this policy. The quota system in some US states specifically regulates the percentage of photovoltaic power generation that must be achieved.