Recently, the National Development and Reform Commission and the National Energy Administration issued the Tentative Measures for Promoting the Construction of Grid connected Microgrids (FGNY [2017] No. 1339) (hereinafter referred to as the Tentative Measures), which was issued in a very timely manner and is of great guiding significance for promoting the healthy development of microgrids and even multi energy complementary systems.

In order to cope with the development of large-scale distributed clean energy and improve the power supply security of the grid, it is generally believed that there are two technical routes to choose:

First, increase the input of main network equipment and adopt a wide range of coordination control technology;

The second is to develop small and micro energy systems to achieve local energy balance through small-scale source network load management, that is, to develop micro grid technology in line with the structural reform of the energy supply side.

Compared with the former scheme, the micro grid technology can delay or reduce the investment of the superior grid, and has flexibility and value in case of main grid failure.

There is no doubt that under the background of large-scale distributed clean energy development, microgrid, as an effective management scheme of distributed power generation, has become an important development direction of modern power grid. At the same time, we must note that the absorption of distributed generation is not only a problem of power technology, but also a problem of power market mechanism. It has been more than two years since the new round of power reform. Reviewing the detailed rules of the relevant documents of the "No. 9 Document", each of them is targeted, but few documents involve issues related to the micro grid market mechanism.

Although microgrid can solve the grid connection demand of large-scale distributed power generation from the technical level, it will further improve the utilization efficiency of distributed renewable energy in microgrid combined with effective market mechanism; At the same time, China is vigorously promoting the construction of terminal integrated multi energy complementary system. Microgrid is one of the solutions for integrated optimization of multi energy complementary system.

The author believes that the specific significance of the Trial Measures is as follows:

(1) The concept of micro grid development is unified, which is conducive to promoting the commercialization of micro grid.
For a long time, hundreds of schools of thought have been arguing about the definition of micro grid, and there are differences in understanding of system capacity and functional structure at different levels. In addition, there are always disputes about who is the microgrid investor and what are the profit models.
The Trial Measures have detailed the connotation and extension of microgrid, which is more practical than the previous microgrid documents. It not only unifies the development concept of microgrid at this stage, but also helps to explore a development path of microgrid that is suitable for China's national conditions.

(2) The micro grid guarantee mechanism has been standardized to improve the utilization rate of distributed renewable energy in the micro grid.
For a long time, due to the problems of grid connection technology and market mechanism, the distributed generation mainly adopts the self use mode, and the surplus power is connected to the Internet or not. Microgrid technology can adjust distributed power generation resources within a certain range. The Trial Measures guarantee the unified management and scheduling of microgrid for distributed power generation resources from a mechanism, which is of great significance for improving the utilization rate of distributed renewable energy in microgrid.

(3) It has innovated the micro grid market mechanism, which is conducive to the healthy development of terminal integrated multi energy complementary system.
China is vigorously promoting the construction of a multi energy complementary system. The terminal integrated multi energy complementary system is conducive to promoting on-site clean energy production and consumption, and improving the overall energy efficiency. There is no doubt that microgrid integration is an effective solution for energy interconnection.
However, in addition to the complementary characteristics of energy technology itself, the market mechanism is the key to effectively achieve multi energy complementation. The Trial Measures have innovatively stipulated the operation mode, transaction mode and profit mode of the micro grid, which will be conducive to the healthy development of the terminal integrated multi energy complementary system with the micro grid as the carrier.

(4) The identity of the micro grid as the main body of the ancillary service market is affirmed, which is conducive to the large power grid to ensure the safe operation of the grid by means of regulation.
One of the starting points of micro grid technology is to solve the security problem of large-scale distributed generation grid connection. Through the unified dispatching management of micro grid, it can not only reduce the impact of distributed renewable energy grid connection, but also provide effective active power support and reactive power support for the large grid.

The Trial Measures clearly encourage microgrids to participate in ancillary service transactions as independent ancillary service providers, which enriches the regulation means of large power grids and is conducive to improving the safe operation of power grids in the context of large-scale distributed renewable energy grid connection.

In a word, this document is of great significance for promoting energy miniaturization and clean development. As stated at the beginning of the document, the document was issued to "promote the structural reform of the energy supply side, promote and standardize the healthy development of micro grid, guide the local consumption of distributed power and renewable energy, establish a diversified integration, supply and demand interaction, allocation of energy production and consumption mode, and promote the construction of a clean and low-carbon modern energy system". It is reasonable to believe that with the release of this document, the commercialization of grid connected micro grid will usher in spring.