Haibin Wan1, Yang Cao2 Wei Wang1, Qingrun Yang3, Dongil Lee4, Tao Ding3, Huiming Zhang5

1. Global Energy Interconnection Development and Cooperation Organization, Beijing 100031, China

2. China Electric Power Research Institute, Nanjing 210003, China

3. Department of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China

4. Seoul National University Electric Power Research Institute, 1 gwanak-ro, Gwanak-gu, Seoul 08826, Korea

5. State Grid Yangquan Power Supply Company, Yangquan 045000, China

Abstract: In recent years, the global energy interconnection (GEI) has more and more profound influence around the world, which is a highly practical way for humans to handle the energy crisis. In the studies of GEI, the economic dispatch (ED) is a basic and important content. In this paper, a model of dynamic economic dispatch (DED) of GEI is presented, which include the renewable energy generation. The objective function of this model is composed of the operating costs and the renewable energy curtailment. A series of case studies for the transnational energy interconnection in Northeast Asia are given to verify the superiority of GEI and for further analysis.

Keywords: Global energy interconnection, Dynamic economic dispatch, Renewable energy resources.

During the almost three hundred years of industrialized process, a huge number of fossil energy has been exploited and utilized, which gave a profound promotion to development of the global economy and human society. However, the problems are more and more prominent that the nonrenewable fossil energy is nearly exhausted, along with the phenomenon of environmental pollution and climate change. Therefore, it is obvious that human society can hardly survive with the traditional method of energy utilization, and the energy revolution is extremely urgent. One important part of the energy revolution is the widely using of renewable energy resources, for example, wind energy and solar energy. The renewable energy resources have unexhausted reserves all over the world and are friendly to the environment, which could satisfy the increasing energy demand of human society. Nevertheless, the allocation of renewable energy resources is pretty unbalance among countries and regions, for example, there are abundant wind energy resources in the Arctic, which has few energy demands. Moreover, such a natural distribution is unchangeable, which cause more challenges to the optimal utilization of renewable energy resources. Based on the background above, the concept of “global energy interconnection (GEI)” has been proposed, which has aroused more and more attention around the world. The GEI aims at developing a global power grid, which can transmit the electrical power converted from renewable energy resources and other forms of energy all over the world, become the vital hub of the energy allocation optimization, and promote the smooth progress of energy revolution.

Fig. 1 Diagram of economic dispatch for

global energy interconnection

The significant features of GEI mainly include:

1) Extensively interconnected. This is the most fundamental feature of GEI, which has plentiful meaning. From microgrids to regional distribution networks, intracontinental power grids to intercontinental power grids, every part no matter huge or small is connected closely and develops coordinately, making a complete system of GEI.

2) Strong and Smart. The power grids are the most complex dynamical system, and GEI is the highest form. The flexible and stable operation, as well as the robust adaptation and self-healing capability of GEI, both need the most advanced techniques to support and make the GEI strong and smart enough.

3) Open and interactive. The well cooperation of countries is of great necessity for the GEI. Thus, the construction and operation of GEI must be open and equal for each country. In addition, the load side should also participate actively in the GEI to realize the two-way interaction between the grid side and load side. Among the studies of GEI, economic dispatch (ED) is a basic and vital content. Generally speaking, the ED is an optimization problem aims to minimize the operation cost of power system while satisfying various constraints. From the view of time scale, the ED problem can be divided into two kinds: static economic dispatch (SED), and dynamic economic dispatch (DED). The SED only considers the ED problem with one single time period, i.e. the connections among different time periods are omitted. Oppositely, the DED fully considers the coupling relationship of different time periods, for example, the ramp limits of units. Despite that the DED is more complex, it can better reflect the reality of system operation, and get more practical results. In the GEI, the penetration of renewable energy generation is large, which bring more volatility to the system and make a closer connection of time periods. If SED is applied to the GEI, probably the dispatching results will be infeasible. Thus, DED is a better choice for GEI and used in this paper. As it is mentioned above, the ED is an optimization problem which has its objective function. In the traditional ED, the objective function mainly consists of the fuel costs of thermal units. However, this cannot meet the various requirements of GEI, for instance, the sustainability. Thus, multi-objective function, should be introduced into the ED of GEI. One common method to handle the objective functions with different dimension is distributing certain weight coefficients to them and adding components into one single objective function. In this paper, the curtailment of renewable energy generation is put into the objective function to balance the economy and sustainability.

The rest of this paper is organized as follows. Section 2 gives the model of DED for GEI, which including the parts of renewable energy generation. Section 3 presents the case studies of the application on the transnational energy interconnection of Northeast Asia, and the conclusion is followed in Section 4.