Grid connection: How the application to the grid company works

An industrial BESS (battery energy storage system) must be connected to the collective electricity grid before it can be used. That connection does not happen by itself; it goes through an application to the local grid company, the distribution system operator that owns and operates the electricity distribution network in the area. For a decision-maker, that process is often invisible until it becomes a timing factor in the project. It is not about the battery itself, but about an agreement document, some technical annexes, and an administrative process whose duration cannot be predicted in advance.

This article walks through how the grid connection application works in practice: when it is triggered in the project, what documentation must be submitted, who does what, why processing time varies, and what happens if capacity in the grid is not sufficient. The question of why a grid connection of around 400A is a practical benchmark for when a system makes sense is covered in its own article in this guide and is not repeated here.

When the application is triggered in the project

The application to the grid company does not belong among the very first steps. It assumes that the scope of the system is clarified: how much power the system must be able to draw and send, where on the plot it is placed, and which connection point is needed. That comes after the initial dialogue and the contract that sets out the turnkey process, which we describe separately in the guide. Only once the framework is known does it make sense to approach the grid company with a concrete case.

In practice, the grid process runs in parallel with the rest of the project. While the battery is ordered and is in production and transport, we work with an authorised electrical installer to prepare and submit the documentation the grid company needs, and to get the connection point determined. The grid application is therefore not a standalone step, but a track that runs alongside the physical preparation work on site until the system can be put into operation. It is also one of the tracks that can become a bottleneck, because the time horizon lies outside what a supplier can control.

The typical starting point: an existing connection

For most of our industrial turnkey projects, the grid process builds on an existing grid connection at the address. The company often already has a delivery scope of 400A or more, and the task is usually to obtain an amended grid connection agreement, not to establish an entirely new physical connection to the electricity grid. The central point is typically to agree an injection scope, bi-directional metering, and the technical terms, so the system can legally both draw and send electricity. That type of case processing can still take time, but it is a different process from physically expanding the grid, which is described further below as a rarer exception. On site, a new switchboard and cables may still need to be established, but that is work on the company's own installation and is not the same as expanding the grid company's network.

The grid connection agreement: the document that sets the framework

The core of a grid connection is an agreement document. The grid company prepares a grid connection agreement, in some processes called an ordering letter (bestillerbrev), in which all matters around access to the collective electricity grid are described. That applies both when an existing agreement must be amended with a new injection scope for a battery, and in the rarer cases where the grid must be physically expanded or reinforced. It is here that the framework for the system is fixed, and it is therefore one of the most important documents in the entire process.

Three elements in the agreement are central for a battery. The first is the connection point, the place where the installation is coupled to the collective electricity grid. It is the grid company that designates the point based on an overall assessment of capacity in the grid and of the costs of the different connection options. The point is therefore not something the customer chooses themselves. The second is the delivery scope (leveringsomfang), which describes how much power the system may draw from the grid, stated in amperes or kilowatts. The third is the injection scope (indfødningsomfang), which describes how much power the system may send back to the grid.

It is precisely this last part that makes a battery different from an ordinary consumption facility. Because a battery both draws and sends electricity, a connection requires that both a delivery scope and an injection scope are agreed, that is, rights in both directions. Beyond the three elements, the agreement also describes the ownership and operational responsibility boundary, the physical and technical requirements, establishment of settlement metering, and payment. The application is therefore in practice about reaching this agreement.

Documentation and technical annexes

The path to the agreement goes through an installation form, in everyday language called an ISB. The customer's electrical installer must complete and submit an ISB to the grid company as early in the process as possible, because it is a precondition for connecting the installation to the grid, for choosing an electricity supplier, and for installing a meter. It is important that the information in the ISB matches what is stated in the grid connection agreement, so the two documents describe the same system.

That it is an electrical installer who handles the technical submission is not accidental. Work on fixed electrical installations may only be carried out by an authorised installation company approved by the authorities, and it is therefore the authorised company that delivers the necessary technical documentation to the grid company. For solar and batteries, this documentation must show that the system meets the applicable technical requirements for that type of system. Part of that assessment is eased through an industry scheme in which certain units have in advance been reviewed for compliance with Danish grid requirements, so the grid company does not need to review every individual system in detail.

A final technical matter is metering. Before a battery may deliver electricity to the grid, the settlement meter must be configured for bi-directional metering, so that both what the system draws and what it sends back can be measured separately. This too belongs to the electrical installer's tasks in connection with registering the system. Taken together, the application therefore does not consist of a single form, but of a grid connection agreement, an ISB, and the technical documentation showing that the system can be connected safely.

Who does what in the application

For a decision-maker, the essential question is often how much the company itself must handle. In our turnkey model, we prepare and handle the grid application together with the electrical installer, so the company does not have to navigate the grid company's systems or handle the technical dialogue themselves. That is part of the coordination a customer pays for.

There is, however, a boundary worth knowing. A grid connection agreement is an agreement between the customer as system owner and the grid company, not between the grid company and us. It is therefore the customer who, as owner of the system, is the formal contracting party towards the grid company, while we prepare the supporting documentation and coordinate the process towards the agreement. In practice, the customer experiences it as a simple task, because the work has been done in advance, but it is still the system owner who stands as party to the agreement itself. Throughout the process, the company has one fixed contact person with us, so the same person knows the project from the initial dialogue through the ongoing dialogue with the grid company and the electrical installer.

The decision itself sits with the grid company, which designates the connection point, sets the technical terms, and ultimately decides on what conditions the system can be connected. The role split is therefore clear: we coordinate, the electrical installer carries out and submits the technical material, the customer is the contracting party, and the grid company makes the decision. The grid connection is at the same time only one of several authority tracks. A building permit is a separate track, where it is the individual municipality that handles building cases and can set local frameworks via a local plan, and that has its own article in the guide. Energinet, Denmark's national transmission system operator, and the system requirements that apply beyond the grid connection itself also belong to a different stage, which is covered separately.

Processing times: why there is no fixed date

The question that comes up most often is how long the application takes. Here the honest answer is that there is no fixed processing time that can be promised in advance. Only once the grid connection agreement is entered into does the grid company's project manager contact the customer and agree a start time and an expected date for when the system can be put into use. The expected date is therefore something that is fixed along the way in the specific case, not a figure that applies across all projects.

The reason is that processing depends on the state of the grid exactly where the system is to stand. In most cases, the time horizon is primarily about processing an amended connection on existing infrastructure: can injection scope and metering be approved within the capacity already allocated? In exceptional cases, the grid company must examine whether there is already a spare point in the grid, or whether a new connection point must be built, and that affects how long the case takes. If there is spare capacity at the existing point, the connection can often happen more quickly. If new grid must be established, it requires excavation work, an excavation permit from the municipality, and consideration of other cable owners, and then the process takes considerably longer. Two otherwise similar systems can therefore have very different time horizons solely because of local grid capacity. For a timeline, that means the grid process should be treated as an estimate with uncertainty, not as a fixed delivery date, and that it is worth starting early.

When capacity is not sufficient

Grid connection is not a formality, and it cannot be guaranteed in advance. An important starting point is that an existing delivery or injection scope is not in itself the same as capacity for a battery. That a company already has a large connection therefore does not automatically mean that a battery can be added within the same framework.

If capacity is not sufficient, there are typically two outcomes. One is a redesign within the existing connection, for example adjusted placement or sizing, so the system fits the terms the grid company can offer. In rarer cases, the grid company designates a different connection point that lies further away or requires the grid to be reinforced, which can change the project's scope, timeline, and economics considerably. The second, and more far-reaching, outcome is that a sufficient grid connection cannot be realised after a reasonable attempt. If that happens, the project may end after the contract, and payments are handled as agreed in the contract. There is therefore no universal guarantee that all amounts are always repaid in every situation; handling follows the specific contractual terms. This possibility is rare, but it is a real precondition that is better to know from the outset than to discover mid-project.

ZynexGroup's approach to system assessment

We treat the grid application as a separate track that we steer in parallel with the rest of the project, precisely because this is where part of the timing uncertainty sits. In the initial assessment, we therefore look early at the size of the grid connection and at what the consumption profile says about the technical headroom, so we can form a picture of whether a system is realistic at all at the address before time is spent on an actual application.

Once the project is underway, we handle the dialogue with the grid company together with the electrical installer and keep the technical annexes consistent with the grid connection agreement. Our role is to make the process as simple as possible for the customer and to be honest about what we cannot promise. We can prepare the application package thoroughly, but we can neither designate the connection point nor guarantee a particular processing time, because both are decided by the grid company and by the capacity available in the grid at that location.

Overall perspective

The application for grid connection is in practice the path towards a grid connection agreement that fixes the connection point, delivery scope, and injection scope for the system. It builds on an installation form and technical documentation that an authorised electrical installer submits, and a battery requires rights in both directions because it both draws and sends electricity. We prepare and coordinate the process, but the customer is the contracting party towards the grid company, and it is the grid company that makes the decision. Processing time cannot be promised in advance, because it depends on whether an amended agreement on an existing connection can be approved within a reasonable time, or whether the case ends in physical grid expansion. A company that knows those frameworks and starts the grid track early has the best starting point for a realistic timeline.

Have the potential for your facility assessed

If you are considering an industrial BESS, the natural starting point is the data that are also decisive for the grid side: your grid connection in amperes, your consumption profile, and your historical consumption data. We use that type of data for an initial assessment of whether there is a match, and for a data-based dialogue about the further process, including what a grid connection at the address realistically involves. You are welcome to contact us here.