Low-carbon new knowledge: The integration of new energy and smart grid is a major trend

Climate change and energy shortage are the largest public crisis ever encountered by humans. The transition to a low-carbon and green economy has become a major trend in the world economy. Energy conservation and emission reduction, green energy, and sustainable development have gradually become a concern in various countries. Focus. Governments of various countries have begun to realize the importance of smart grids in promoting the development of low-carbon technologies and increasingly regard smart grid construction as a strategic infrastructure investment.

In order to effectively promote the integration of new energy and smart grid technology and industrial development, on October 21, the Shanghai Songjiang District Economic Committee and the Shanghai New Energy Association jointly organized Ningbo Xingnuo Venture Capital Co., Ltd. to organize experts in the Shanghai Smart Grid Industry Base. Scholars, leaders of government management departments, industry experts in scientific research institutions, industry elites, leaders of industry associations, in particular, invited technical experts engaged in the integration of new energy and smart grid technologies and made breakthroughs in innovation, jointly held a "new energy and smart grid Technical and practical seminars."

Participants generally believed that improving energy efficiency and the use of renewable energy and reducing greenhouse gas emissions are inevitable trends in the future development of the power grid. They also discussed the various countries’ current proposals for smart grid concepts and plans. They all agreed that one can be integrated. The distributed renewable energy smart grid is the direction of the national energy strategy and the only way to reform the energy layout.

The development goal of the smart grid is to build a modern, energy-saving, environmentally-friendly, highly-efficient, reliable, and stable power grid. One of its core issues is to address the access and effective deployment of various new energy generation in distributed energy sources, as well as the issues of safe, reliable, and stable operation. .

Solving the problem of integration of smart grids and distributed energy sources is a “heart disease” in the power industry in the world. This is because a series of problems such as instability of wind energy, solar photovoltaic and other renewable renewable energy generation, low operability, poor access to grid technology, and impact on the harmonic management of the grid are still to be resolved; The concept of many problems was put forward. Although they differed, they all realized that building a microgrid in a decentralized manner and accessing the distribution network to balance the ground, strengthening user-side interaction and management, and promoting the use of distributed power, Promote the development of smart homes and accelerate the construction of smart grids and interactive service systems.

It can be said that the end users of the smart grid, which is one of the important players in the future, are the single grid users who are using distributed power such as wind power generation and solar power generation in the new power market. Its goal is to increase the capacity of its own power generation equipment from a few hundred watts to several hundred kilowatts, with a stand-alone capacity of less than 100 kilowatts, for its own use. The excess power is self-distribution sold or sold to the power grid, on the low-voltage side of the distribution network ( Or the user side) builds its own network or connects to the network. The intelligent controller automatically controls the networking or the conditions for the network connection. When the networking or network connection conditions are met, the network is automatically connected or networked. If not, the network is off-line at any time. For home users with power generation equipment capacity of a few hundred watts to several kW, they can be “plug and play” through 220V outlets.

In China, the State Grid Corporation's strong smart grid is more about how the national grid is playing chess, building its high-voltage, ultra-high-voltage transmission network, and making its transmission network more optimized, especially the integration of cross-regional resources, and strong The power backbone network framework is the basic framework of security support necessary for any model of smart grid. The intelligent energy information framework and control and deployment analysis and decision model are the carriers for implementing smart grid technology. In particular, flexible access to distributed renewable energy will be Achieve the peak of the smart grid.

However, China's smart grid is currently facing tremendous pressure and challenges in accessing and using the distributed generation of power generated by solar power generation.

Taking solar power as an example, in terms of technology and market models, there are currently two approaches. First, grid-connected power generation and sale to electric power companies require energy storage—transmission—transmission, and even two after entering the grid. Sub-transformation and supply to users after distribution; this process investment increased by about 30%, and resources consumed nearly 30%. It is expensive solar energy system itself (approximately 30-40 yuan***/watt investment) for one year The return on electricity generation is only one yuan and more (in terms of one yuan/degree), and the return rate is only 2.5% to 3%. Due to huge subsidies from the government, China subsidizes about 20 yuan per watt (or 50% to 70% of the investment amount), and the subsidy for purchasing electricity prices is 1.5 to 2.5 yuan per degree, making investors 10% to 15%. s return. However, the government’s burden is huge, with a subsidy of about 20 yuan per watt, and future tariff subsidies cannot be discounted. Each watt still costs 2 to 4 yuan per year. The “plan” proposes that solar power be 1.8 million kW by 2020. As a result, it is calculated that the country should bear a subsidy of 460 billion yuan, and that it should also bear the annual electricity price subsidy of about 36 billion yuan. However, this is only one-third of the U.S. solar roof's planned power generation capacity; equivalent to Japan's 2007 solar power generation capacity.

Another way is to use the island form, one-one-one-system, self-installation, and one-time subsidies provided by the state, which is adopted by China in the remote areas (rural areas). This method is difficult to get rid of relying on days to generate electricity and rely on electricity for days. Limitations, in order to improve the application effect, only increase investment, increase solar power generation equipment, increase battery capacity, such a result is a good time waste, bad weather is not enough, and when the use of electricity is not enough, when not in use Needs to be discharged (this condition occurs when the family travels for a week) and there is no guarantee for the user's electricity use.

As the system power generation is not only too small, it is impossible for the islanding mode to achieve network sharing or network sharing or complementation, and its use quality and efficiency are greatly reduced.

At a deeper level, solar panels (most of them are crystalline silicon materials) have a high power consumption during the material production process. It takes only 5 to 7 years of power generation to make up for it, and investment subsidies for national support are also double-edged swords. From a strategic point of view, resources are stored and coal and electricity are stored on solar panels. On the other hand, when grid technology and conditions are not available, distributed energy applications will need to be transfused in order to survive. It caused huge investment waste and resource depletion, and its scale and degree are also alarming.

Therefore, although global experts do not have a common conclusion, they collectively recognize that with the advancement of technology, it is foreseeable that the future grid will gradually get rid of the model of single centralized power generation in the past and turn to the mode of distributed generation-assisted centralized power generation. At the same time, when a large number of distributed power sources are integrated into the large power grid, most of them are directly connected to the distribution network at all levels, making the power grid from top to bottom a power exchange system that can flow in both directions on the branch roads, but the current distribution system The electric network is designed according to one-way flow and does not have the technological potential to effectively integrate a large number of distributed power sources. It is difficult to handle the uncertainty and intermittent nature of distributed power sources, and it is difficult to ensure the reliability and safety of the power grid. The problem is very prominent. It can be seen that the important direction of distributed energy technologies and markets is to establish a microgrid that is both independent and controllable and integrates with the smart grid.

In this regard, China's engineering and technical personnel have made unremitting efforts and innovations. Among them, the "hybrid power intelligent deployment technology" proposed by the senior engineer of the patented inventor and senior engineer Zhou Xiwei is a model example of micro-net R&D practice. The hybrid power smart distribution system announced at the “New Energy and Smart Grid Technology and Practice Symposium” held in Shanghai has achieved a good multi-energy power input and multiple power power output both technically and practically. Intelligent nodes, digital interconnection, free interconnection between nodes, automatic resource allocation and sharing, automatic building and forming of micro-grid and multi-microgrid interconnection and intercommunication; also can be used as a single controllable independent user system of the power grid. The connection of large power grids solves the problem of distributed energy access to the power grid, realizes complementary power, enhances the performance robustness of both the large power grid and the microgrid, and improves black start capability.

The practice of hybrid power intelligent deployment technology adopts advanced multi-sensing and two-way monitoring and metering technology, advanced electronic power module technology, advanced multi-agent automatic control method, and unique “periodic relationship” path continuation method, etc. Technologies and methods to achieve a free network and advanced intelligent decision-making and deployment model and support system technology to form a safe, efficient, environmentally friendly microgrid. The system solution of the hybrid power intelligent deployment technology breaks through the existing power supply mode of the power market and is a real solution to the two-way interactive management of the user side compared to the dominant technology solution of the smart grid that is currently popular in the world. Smart grids based on smart meters give users limited information, especially when the user is always in a passive interaction mode. Users can freely network, plug and play, buy electricity, sell their own electricity; users have the opportunity to shift from passive to active in the electricity market, from one-way to two-way, to recover the dignity of the user of equality and mutual benefit.

According to the preliminary estimation of research and practice, researchers use the micro-grid composed of hybrid electric power intelligent deployment technology. Compared with the grid-connected method, the investment can save about 30%, and the overall efficiency can be increased by about 30%. Therefore, the investment efficiency is relative to the grid connection. The method can be more than doubled. The user-level hybrid power smart distribution system based on the microgrid, which does not require the government to subsidize the electricity price, estimates the annual electricity price by more than 8% based on the calculation method of the ladder power price. Solar power generation can still survive if the government does not pay the price subsidies each year, ie it does not "transmit blood."

As the microgrid-based user-class hybrid electric power smart distribution system can easily form a microgrid, and can be used as a single controllable independent user system of the power grid, it is well connected with the large power grid, solving the user-side power generation and networking. The access problem of the network has reduced the threshold for investment and grid connection, making it easy for private capital and even the capital of the people to enter the new energy power market, which will help speed up the construction and development of new energy and smart grids.