Energy Storage Models: Four Configurations for Business

Energy storage models differ in whose network the system connects to, who uses the stored energy and how its operation is organized. The same battery can be part of an enterprise, work together with a power plant or be part of a separate energy project. Therefore, the choice begins with the scheme of use, and not with the name of the equipment.

For a preliminary comparison, consider four basic configurations: a separately connected ESS, storage at a generator’s site, a consumer’s ESS and a shared connection point. These describe how a project is organized, rather than four mutually exclusive ways to earn revenue. First define the main task and the required inputs, then assess the appropriate arrangement. Its name alone does not establish permitted operations, equipment requirements or financial results.

Connection layout and purpose: two different questions

The connection diagram shows the electrical connections and boundaries of responsibility. The purpose answers a different question: why the storage system is charged and discharged. This can be shifting solar energy to the evening, maintaining selected equipment, reducing peak grid demand or working in the electricity market.

For example, a storage system near a solar power plant can accumulate production for further sale. At another facility, similar equipment helps to use its own generation in the production process. The sites may look similar from the outside, but the accounting, contracts, governance and success criteria will be different.

The owner of the equipment and the person who will manage the modes are determined separately. The location of the battery on the premises of the enterprise does not yet explain who owns it, who buys the energy for charging and who is responsible for operation. These questions should be recorded before comparing commercial offers.

Separately connected ESS: independent power facility

In this model, the installation has its own connection to the transmission or distribution system and is used for independent energy storage activities. Charging and subsequent discharge are considered together with available network capacity, commercial accounting and organization of market work.

Important distinction: a separately connected ESS does not mean a stand-alone system without a power grid. Such a facility, on the contrary, may depend on the ability to import and export electricity through its grid connection. If the task is to provide a facility without reliable external power, autonomous energy solution should be considered separately.

For an independent project, the permitted capacity is checked in two directions. The ability to export a given amount of power does not imply that the same capacity is available for charging. Also needed are those responsible for management, accounting, contracts and commercial results.

Generation at the site of the ESS operator is also possible as a separate configuration. Therefore, the conclusion "there are solar panels, therefore it is always the generator’s model" would be too simplistic. The role of the participant and the actual organization of the entire facility are important.

ESS at the site of the electricity producer

The storage facility can be connected to the generator’s internal electrical networks, such as a solar or wind power plant. Its work is related to the generation schedule and the subsequent use or export of the stored energy. For this configuration, the concept of co-location with generation is used.

Storage may help shift some generated energy to another time, adjust the export schedule and reduce some losses of potential generation. But the battery does not eliminate all network constraints: its capabilities depend on free capacity, charging power, generation forecast and control settings.

The combined operation of the solar plant and storage system is checked at the connection point. If a station is already using the available export capacity, adding storage alone does not increase this limit. In the same way, the charge from the network must be compared with the available import capacity, and not only with the power of the equipment.

Economic comparison should consider the entire facility: the mode without storage and the mode after its integration. The potential reduction of imbalances or the transfer of sales should not be recorded as guaranteed income. For a new solar project, initial site and consumption data can be prepared through site audit for a solar plant; the scope of individual works on ESS is additionally agreed upon.

ESS of the enterprise for its own needs

At the enterprise, the storage device can work in internal electrical networks and provide energy to its own consumers. Among the possible tasks: use of daytime solar surplus later, reduction of peak grid demand and backup for specified loads. Each function must be confirmed by the system composition.

Self-consumption of solar energy requires a comparison of two schedules: production and operation of the enterprise. If a significant part of the generation is already consumed immediately, it is not possible to automatically assume a large amount of additional savings from its accumulation. For a complex task with solar generation, a battery and the grid, it is appropriate to consider a hybrid system for an enterprise.

Power backup is a separate technical scenario. It is necessary to determine the load, the permissible interruption, the order of switching and the energy reserve. The presence of a battery does not confirm the ability to work in the event of a network failure. For a production facility, start by selecting the processes that need backup production power supply.

Use only for own needs and participation in the sale of electricity should not be described in the same way. If an export to the grid is planned, the proper participation model, connection conditions, accounting and contracts are checked separately. Installation of equipment in itself does not solve these issues.

The active consumer model combines consumption with other permitted operations, including storage. It should not be identified with any company that purchased the battery. For the future sale of energy, the legal status and relevant operating conditions need to be defined separately, not just adding a function in the software.

An option with another owner's ESS at the consumer's site is also possible. Access to equipment, control, maintenance, energy use and billing must then be agreed upon. The legal regime of such interaction is checked for a specific configuration.

A shared connection point: what to agree on

Several electrical installations can use a common network infrastructure or connect through the networks of another user. The main issue here is the organization of shared access, not just that the battery is next to the solar panels.

For such a project, it is necessary to define users, rights to the infrastructure, limits of responsibility, accounting procedure and flow management. It is important to find out in advance which modes have priority when several installations need available network power at the same time.

The sum of the nameplate capacity of the equipment is not equal to the authorized capacity of the common point. The actual combined import and export through it is evaluated. A shared cable or transformer does not create an unlimited opportunity for all participants at the same time.

The technical solution must be consistent with the contracts and applicable connection rules. The model name is not a substitute for checking these conditions. For the initial discussion, it is useful to draw one diagram with owners, meters, connection points and possible directions of energy flow.

Comparison of four configurations

This is a guide for describing the project, not a list of mutually exclusive ways of earning. Infrastructure sharing can be combined with generation or consumption. The final configuration should be described in more detail than a single term in the vendor's presentation.

How to compare the result of different models

First determine which baseline the project is being compared against. For an enterprise, it can be the current schedule of purchases and consumption. For the owner of the power plant, production, restrictions and adherence to the export schedule are important. For an individual ESS, its own operations and costs are considered. Mixing these initial conditions makes the comparison incorrect.

Next, separate energy sales from cost savings. Reduction of purchases by the enterprise and income from sales outside the facility have different meanings. Not every saved kilowatt-hour can be counted towards both results at the same time. Also consider charging energy, losses, installation availability, and mode effects on battery life.

Comparing scenarios requires a common horizon and agreed assumptions. Check what will change with lower solar generation, a different load or a less favorable price difference. Such a comparison shows what the result depends on. It is more useful than the promise of equal payback for all four configurations.

If market activity is considered, determine in advance who will plan the charge and discharge, monitor the fulfillment of obligations and analyze the result. These functions may be performed by an in-house team or by an appropriate partner to an agreed extent. The purchase of equipment does not replace the organization of daily management.

How to go from task to model selection

1. Identify the main need. Support the production process, use more of your own generation or create a separate energy asset.
2. Describe the existing facility. Generation, consumption, network and equipment owners, installation location, current connection points.
3. Match the modes. When charge is available, when energy return is required, what constraints occur simultaneously.
4. Prepare input data. Schedules, connection documents, accounting scheme and list of persons responsible for operation.

Illustrative example: a business with solar generation has an evening shift and a critical load. It may consider using the day's surplus in the evening and at the same time require a minimum backup reserve. However, the energy spent on evening work can no longer be considered a constant reserve. In the task, you need to determine the priority and the minimum allowable stock.

Similarly, the same available capacity cannot be taken into account twice for different commitments at the same time. The combination of modes requires resource allocation by time and volume. This applies both to the internal needs of the enterprise and to market operations.

After choosing the arrangement, proceed to determining ESS power and energy capacity. Then compare specific equipment, for example by checking the Sungrow PowerTitan 2.0 documentation. Match the proposed power, usable energy and controls to the required operating schedule. Separately confirm the connection and backup capability if needed. The model name does not establish suitability for every scenario or facility.