How does a BESS affect a company's electricity bill?

When a company considers installing an industrial battery energy storage system (BESS), a very concrete question often comes from the finance function: will this disrupt our electricity bill? The concern is reasonable. The system sits behind the company's own meter and is used actively for trading on the electricity market. So what actually happens to the bill you already know?

This article explains how a behind-the-meter system relates to your existing electricity consumption, which ongoing costs we carry, and how we handle the two areas where our commercial use of the system can in principle touch your economics: extra capacity tariffs or grid costs, and electricity from your own solar panels. The aim is to make clear what changes, and what does not.

What "behind the meter" means

Behind the meter describes where a system is placed relative to the company's electricity meter. A behind-the-meter battery is located on the customer's side of the meter and therefore forms part of the customer's own electrical installation, in contrast to a front-of-the-meter system, which is connected directly to the grid on the producer or grid-operator side. The difference concerns, among other things, who owns the system, where it stands, and how it is used.

For you, that means the battery physically lives inside your installation, on the same side of the meter as your production equipment, lighting, and other consumption. It is a technical prerequisite that your installation has the necessary capacity (sufficient switchboard capacity, connection, and power) to accommodate the system. But placement behind the meter does not in itself change how you buy your ordinary electricity. That distinction is the core of the rest of this article.

Your electricity bill continues unchanged

The most important point first: you continue to pay for your own electricity consumption, exactly as you do today. The system does not replace your electricity supply contract and does not change your electricity supplier, unless we expressly agree otherwise.

It helps to remember what a Danish electricity bill actually consists of. The bill combines several parts: the electricity itself, paid to the electricity supplier; transport of electricity through the grid (grid tariffs); taxes to the state; and VAT. Everything is collected in one combined bill from the electricity supplier, which then distributes payment onwards to the other parties. Transport is handled by your local distribution system operator (the company that owns the local electricity grid), while the overarching transmission grid is operated by Energinet, Denmark's national transmission system operator.

When we optimise the battery, that does not change this basic structure. Your own consumption continues to be metered and settled as before, and ordinary variation in your electricity price or your own consumption does not in itself give rise to separate settlement between us. What the battery does is charge and discharge at different times, so the system's flexibility can be used commercially. We keep that activity economically separate from your own electricity trading, with the two clarifications on capacity tariffs and solar panels that we describe further below.

Which ongoing costs we carry

A battery that is controlled and traded actively also draws on some resources of its own. It needs to communicate, be controlled remotely, and be monitored, and it uses a small amount of electricity when it stands in standby. The question for a CFO is straightforward: who pays for that?

In the standard model, we carry the costs that specifically relate to our commercial use of the system. That includes standby consumption, the control systems (EMS and BMS, meaning the energy management system and the battery management system), software, communication and the data connection, plus the router and SIM card. Other operating costs that are directly tied to our optimising the battery in the market also sit with us.

The rationale is that we are the ones with the commercial interest in operating the system. We have the exclusive right to optimise the battery's flexibility during the agreement period, and the operating expenses that optimisation requires belong naturally with us, not with you. In other words, you do not end up with a new row of small items on your electricity bill because the battery communicates with our systems or stands ready to respond to the market. Service follows the same logic: faults attributable to our side, we handle and pay for; faults attributable to your own circumstances sit with you.

When control affects capacity tariffs or grid costs

There is one area where our way of using the battery can in principle affect your grid costs, and it deserves an honest explanation rather than being glossed over.

To understand it, it helps to know that the Danish grid tariff for some customers and grid areas is not only a fixed price per kWh. The newer Danish tariff model makes time-differentiated tariffs the standard, so the price of using the grid varies over the day, and also introduces a capacity charge for customers connected at the highest voltage levels. A capacity charge is linked to how much power is drawn at once. Energinet correspondingly introduces a capacity charge for larger system users connected at 10 kV and above as a price signal on capacity, and prices and methods for tariff-setting are approved by Forsyningstilsynet, the Danish Utility Regulator. How large an element that constitutes depends on customer category, voltage level, and distribution system operator, and it does not apply uniformly to all commercial customers.

That is why capacity matters. A battery that charges heavily at a particular time can in theory raise the power your connection draws in that moment. If our control in a concrete case were to lead to documented extra capacity tariffs or grid costs for you that are not caused by your own consumption, your changes, or circumstances outside our control, the principle is that we compensate you for those additional costs. That is deliberately formulated as a principle and not as a fixed method or a specific amount, because the concrete calculation depends on the actual situation and on the agreed terms. The point for you is the direction: that type of additional cost that our commercial use might create is not intended to land with you.

It is also worth noting that on many sites a battery pulls in the opposite direction. A behind-the-meter battery can reduce an electricity bill by lowering the maximum power drawn and by shifting consumption from expensive to cheaper periods. Precisely charging in hours with low prices and discharging in hours with high prices is part of the value we work to capture. Whether and when that is relevant for your system depends on the overall optimisation and on your consumption profile.

Solar panels behind the meter

If you have your own solar panels behind the meter, a concrete question arises: what happens if the battery is charged with your own solar electricity instead of with electricity from the grid?

The starting point is that that solar electricity is yours. When locally produced electricity is consumed directly behind the meter and is not sent out onto the collective grid, it is not transported through the grid, and it therefore does not enter ordinary grid transport in the same way as purchased electricity. If the battery uses that energy, your own production does not simply disappear into our optimisation without compensation.

Therefore the principle is that if the battery is charged by your local solar production behind the meter, we pay you for that energy at the spot price in the relevant quarter-hour, unless we have agreed something else. The spot price is the price formed on the wholesale market for electricity. In the day-ahead market, also called the spot market, the price is set for each bidding zone, and this is where the majority of electricity trading takes place. The price is no longer formed only once per hour. From October 2025 the spot price on Nord Pool is formed 96 times per day, that is for each quarter-hour, after the day-ahead market moved to a 15-minute market time unit on 30 September 2025. That is the background for settlement per quarter-hour rather than per hour.

That prices are now settled at that resolution is connected to the electricity market having become more volatile. Large volumes of wind and solar have increased price swings, and the shorter settlement period gives more price signals so that consumption and production can be adjusted more precisely. For you, that means the value of the solar electricity the battery uses is settled from the price in the precise quarter-hour when the energy enters, and not from a coarse average.

Limitations and assumptions

The model above is the standard model, and there are assumptions worth knowing. Compensation for extra capacity tariffs or grid costs applies when the additional cost is documented and is not caused by your own circumstances, for example changes in your own consumption, new large electricity consumers, or changes to your installation that you carry out yourselves. Settlement of solar electricity at the spot price in the quarter-hour is likewise a starting point that a concrete agreement can depart from.

The tariff structure is also not the same for everyone. Whether your facility encounters time-differentiated tariffs or a capacity charge at all depends on your customer category, your voltage level, and your distribution system operator. We mention the structure to explain why capacity can matter, not to claim that a particular rate or a particular peak interval applies to you specifically. The concrete figures sit with your distribution system operator and appear in the applicable, approved tariffs.

ZynexGroup's approach to system assessment

We emphasise that the economic relationship around the electricity bill should be clear from the outset, so that doubt does not arise later. When we look at a facility, we look at your grid connection, your consumption profile, and the technical conditions on site. That is also the basis that determines whether and how capacity and tariff conditions can play a role for your specific system.

During the agreement period we have the exclusive right to optimise the system's flexibility commercially, and we carry the operating costs that follow from that use. Software logic, algorithms, and optimisation models are not transferred to you, but remain with us and our partners. A more detailed operations and performance view in the form of a dashboard is on the way, but it is not a finished, live function today, and you are entitled to it only if that is expressly agreed.

We offer a 6-year payback guarantee on BESS systems. That concerns the payment model itself and does not change the principles in this article: that you pay for your own consumption, that we carry the operations tied to the optimisation, and that additional costs from our control as well as the value of your solar electricity are handled according to the principles described.

Overall perspective

A behind-the-meter BESS sits technically inside your own electrical installation, but that does not change the fact that you continue to buy and pay for your own electricity consumption as before. The ongoing costs that specifically relate to our commercial use of the battery, including standby consumption, control systems, software, communication, router, and SIM card, we carry in the standard model.

Two areas can in principle touch your economics, and both are described as principles rather than as fixed amounts. If our control creates documented extra capacity tariffs or grid costs that are not caused by your own circumstances, we compensate you. And if we use your local solar electricity to charge the battery, we pay you for it at the spot price in the relevant quarter-hour, unless otherwise agreed. What remains is a simple picture: your ordinary electricity bill continues on its own track, and the commercial operation of the battery is our responsibility, including financially.

Assessing the potential at your facility

If you want to know how this looks in practice for your specific system, we can have a data-based discussion. We typically look at your grid connection, your consumption profile, and your historical consumption data to make an initial assessment of whether there is a match, and how the conditions around capacity, tariffs, and any solar panels look at your site.

You are welcome to contact us for an initial, no-obligation discussion.