Selling electricity back to the grid pays a per-kWh spot price. The Swedish balancing market pays a capacity fee per MW available per year — regardless of dispatch. These are two separate and additive revenue streams from one battery.
The most common mental model for battery revenue is grid export: surplus electricity flows to the grid and is paid at the spot market price. This is one real revenue stream. The Swedish balancing market is a different and additive one — and understanding the difference clarifies why HNordic's energy income projections are not simply a function of electricity prices.
When a battery or generation asset exports electricity to the grid, the export is settled at the day-ahead spot market price — a per-kWh payment determined by the Nord Pool market for each delivery hour. In Nordic spot markets, the spread between the cheapest and most expensive hours of a day regularly exceeds 10:1. The overnight price may trade below €5/MWh; the evening peak above €80/MWh on the same day.
A battery that charges when prices are low and discharges (exports or supplies building load) when prices are high earns the arbitrage between those prices. This is a real and material revenue stream, particularly for properties with solar generation that charges the battery during the day and discharges during the evening peak.
The revenue depends on the price spread: when spreads are wide, arbitrage returns are high. When the grid is heavily oversupplied — frequent in Nordic markets during periods of high hydro and wind output — spot prices compress and arbitrage returns fall. This is the variable component of the energy income stack.
Svenska Kraftnät (SVK), Sweden's transmission system operator, is legally required to maintain grid frequency within ±0.1 Hz of 50 Hz. As more intermittent renewable generation enters the grid, frequency deviations become more frequent and the volume of stabilisation capacity SVK must procure increases.
SVK procures this capacity through competitive tenders — weekly for some products, daily for others. Battery operators (or aggregators bidding on their behalf) submit bids stating how many MW of battery capacity they can make available for frequency stabilisation, and at what capacity fee. SVK selects the lowest-cost bids until the required volume is covered.
The winning bidder receives a capacity fee: a payment per MW available per year, paid regardless of how much energy the battery actually dispatches in response to frequency events. The dispatch itself — the energy delivered during a frequency event — is settled separately at a defined activation price, but the capacity fee is the primary revenue component.
For a commercial property battery participating in FCR-N (the primary symmetric product), the capacity fee is received for holding the battery available and responding to small frequency deviations continuously. The energy dispatched is typically small and approximately symmetric — the battery charges and discharges roughly equally over the course of a day, so the net energy position is close to neutral. The revenue is almost entirely capacity-based.
A battery operating in the balancing market cannot simultaneously dispatch all its energy for arbitrage — the capacity committed to SVK must be kept available for frequency response. But it can simultaneously: hold a defined proportion of capacity for frequency response; deploy remaining capacity for arbitrage against the day-ahead price; and absorb the building's peak demand to eliminate demand charges.
The AI energy management system manages this allocation continuously. The proportion committed to each use shifts in real time based on which combination is most valuable — more capacity to arbitrage when the day-ahead spread is high; more to frequency response when FCR capacity fees are elevated relative to spread opportunities; and always enough reserved to cover the peak demand reduction obligation.
This multi-axis optimisation is why the AI management layer is commercially essential. A battery managed manually — or on a fixed schedule — can participate in one market at a time. The AI system extracts value from the full stack simultaneously.
FCR-N capacity fees reached unusually high levels in 2022–2023 as new renewable generation entered the grid faster than battery capacity. By 2024, new BESS capacity entering the Nordic market compressed FCR-N prices significantly — more supply chasing the same procurement volume.
mFRR (manual Frequency Restoration Reserve) volumes have expanded as SVK adapts procurement to the changing grid. The per-MW fee for mFRR is lower than FCR-N, but the volume is substantially larger. A battery that can participate across the full product range — FCR-N, FCR-D, aFRR, mFRR, and day-ahead arbitrage — earns materially more than one limited to a single product. This is the market condition that makes multi-product AI optimisation more valuable in 2026 than single-product FCR participation was in 2022.
See also: What are FCR-D, FCR-N, aFRR, and mFRR? · What does the AI energy management system optimise against? · Full FAQ