Summary:

Shared energy storage is one of the solutions to achieve economic consumption of renewable energy. With a moderate investment scale, efforts should be made to match the capacity and power of energy storage power stations with consumption goals. In this regard, a method of capacity and power allocation of shared energy storage power stations considering new energy consumption was proposed. Aiming at the multi-objectives of lowest operating cost of energy storage power stations and optimal economical operation of micro-energy grids, a two-layer planning model was established, in which The layer model solves the power station configuration problem, the inner layer model solves the economic consumption rate and micro-energy network optimization operation problems, and the Karush-Kuhn-Tucker (KKT) method is used to solve the model transformation. The calculation example analysis shows that after configuring shared energy storage, the operating cost of the micro-energy network system decreases and the new energy consumption rate increases. The research results prove that the proposed method of constructing a double-layer planning configuration can better consider the economic consumption of new energy and improve the economics of the operation of shared energy storage power stations and micro-energy grids.

Research Background:

The proposal of the "double carbon" goal marks an important transformation of the power system to renewable energy. As an extension of the large power grid, the micro-energy grid (MG) can realize cascade utilization of energy, complement each other, improve energy utilization efficiency, promote on-site consumption of new energy, and better adapt to the development of renewable energy. Demand plays an important role in promoting the realization of the "double carbon" goal. Traditional micro energy networks are small in scale and have strong load uncertainty. They usually need to cooperate with energy storage devices to complete the translation of energy in time. However, the cost of self-built energy storage devices is high and users are usually unable to afford it, which limits the use of energy storage devices. User-side applications. The current research mainly conducts a preliminary exploration of shared energy storage’s participation in new energy consumption models, and analyzes application scenarios, implementation methods, configuration methods, evaluation criteria, etc. However, most of them focus on the operation mode of micro energy grid. When considering shared energy storage services, there is less research on the specific configuration and operation strategies of power stations. Although some literature uses double-layer planning methods to study the configuration of shared energy storage power stations, the selection of its consumption goals continues the requirement of full consumption of large power grids, and pays less attention to how to achieve economic consumption of new energy. In response to this current situation, this paper proposes a shared energy storage configuration method that considers economic consumption. First, a business model of shared energy storage service multi-micro energy network system in the context of new energy consumption is constructed, and its profit principle is analyzed. Secondly, the impact of new energy consumption on the configuration of shared energy storage power stations is analyzed, and a power allocation method for shared energy storage capacity that considers reasonable power curtailment is proposed. Thirdly, a two-layer planning model was established to solve the configuration of shared energy storage power stations and the economic consumption goals of new energy in the micro-energy network. Finally, a calculation example is set up to verify the configuration method proposed in this article.

Shared energy storage participates in the new energy consumption model of micro energy network:

Shared energy storage is an energy storage commercial application model that integrates traditional energy storage technology with a shared economic model. That is, energy storage power stations are invested and constructed by shared energy storage power station service providers, and energy storage services are provided to users at a certain price. This model allows users to use energy storage systems without high investments. At the same time, it can use the flexibility of the sharing economy to ensure efficient utilization of energy storage systems and achieve rapid recovery of the cost of shared energy storage power stations. The micro-energy network users analyzed in this article are combined cooling, heating and power micro-energy networks (hereinafter referred to as micro-grids), which contain various forms of power flow to meet energy needs such as cooling, heating, and electricity. Internal equipment includes distributed wind turbines, photovoltaics, gas turbines, boilers, heat exchangers, refrigeration machines, etc. The connection between the shared energy storage power station and the microgrid is shown in the figure. The shared energy storage power station consists of energy storage batteries, power station dispatching modules, inverter modules, and support platform systems;

The power station dispatching module in the figure can respond to users' power needs in a timely manner, manage the charging and discharging behavior of the power station, and implement electric energy metering services. Compared with traditional energy storage power stations, the shared energy storage power station bus is connected to each microgrid user respectively. Users can complete power exchange through the power station bus and realize the spatial transfer of power in multiple microgrid systems. The shared energy storage power station measures the charging and discharging energy as well as the energy exchanged between microgrids and charges service fees. Although the power exchanged between microgrids does not flow directly through the energy storage battery, it is also regarded as charging and then discharging by the power station in terms of measurement. . The power station service fee includes the cost of purchasing electricity from the microgrid, selling electricity to the microgrid and additional service fees. It is determined by the power station dispatching module based on parameters such as grid electricity price, microgrid power consumption status and power station charge status.

After considering the shared energy storage power station service, users can choose to purchase electricity from the energy storage power station when the power is insufficient. The electricity price purchased from the energy storage power station is lower than the grid electricity purchase price during the peak period of electricity consumption, and is higher than the grid electricity purchase price during the low electricity consumption period. Electricity prices are used to guide users to purchase electricity from energy storage power stations during peak periods of electricity consumption, thereby saving electricity costs and promoting the full utilization of wind and solar resources.

Principles for capacity and power allocation of shared energy storage power stations:

When an energy storage power station serves a multi-microgrid system, its power capacity needs to be reasonably configured to make full use of the technical characteristics of the energy storage system and take advantage of the shared energy storage business model. Shared energy storage power stations are built in user-dense areas. In site selection, interconnection with multiple microgrid systems must be considered to make full use of the cluster effect and the complementarity of user loads at the same time. Therefore, compared with users configuring energy storage individually, it Lower costs and higher energy storage utilization.

Matlab calculation example running results:

Matalb code + data sharing:

Research on shared energy storage configuration strategy of microgrid groups for distributed photovoltaic consumption - Matlab code reproduction