Optimal battery storage dispatch strategy for your charging site

The clearest indicators that BESS will deliver strong returns at your site are high peak demand charges in your utility tariff, a constrained grid connection that limits the number of chargers you can install, and significant on-site solar generation that is currently being exported to the grid at low rates. If your site has all three of these characteristics, BESS will almost certainly pay for itself within 4 to 6 years. If your grid is unconstrained and your tariff is flat with no demand charge component, the business case is weaker and storage may not be the right investment at this time. Our assessment will give you a clear answer based on your actual data rather than a general recommendation.

BESS sizing depends on three things: how much peak demand you want to shave, how long the peak demand window lasts, and how much time the battery has to recharge between discharge events. A system designed purely for demand charge reduction typically needs to cover 1 to 3 hours of peak load reduction, which for a mid-sized depot might mean a system in the range of 500 kWh to 2 MWh. A system designed to extend grid capacity for EV charging needs to be sized against your total overnight charging energy requirement and the duration of your charging window. We model both use cases and recommend the minimum viable system size that achieves your financial objectives — oversizing a battery is a common and expensive mistake.

For sites with strong demand charge tariffs and constrained grid connections, BESS payback periods typically range from 4 to 7 years depending on system size, local electricity prices, and available incentives. Sites that can also stack grid services revenue or energy arbitrage — particularly in European markets with active flexibility programs — can achieve payback periods of 3 to 5 years. Sites with weaker demand charge structures or unconstrained grids will see longer payback periods, and in some cases storage is not financially justified until the site adds more vehicles or the grid becomes more constrained. Our model gives you the exact figure for your site rather than a range.

Yes, and this is often one of the most valuable configurations for depot sites with rooftop or canopy solar. When the battery is integrated with the solar inverter and the EV charging system through an energy management platform like Ampcontrol, it can charge preferentially from solar generation during the day, store excess generation that would otherwise be exported at low feed-in rates, and discharge to support EV charging in the evening when solar generation has dropped. This increases on-site solar self-consumption — typically from 30 to 40 percent without storage to 70 to 85 percent with storage — directly reducing the volume of grid electricity purchased at full retail rates.

Grid services are programs run by transmission and distribution system operators that pay asset owners to make their flexible loads or storage assets available to help balance the electricity grid. For battery storage at fleet depots, the most relevant programs are frequency response, demand response, and capacity market participation. Eligibility and revenue vary significantly by market — in Germany, the Netherlands, and the UK there are well-established markets where depot-scale batteries can generate meaningful revenue. In North America, demand response programs through utilities are more common than transmission-level grid services for this asset class. Our assessment identifies which programs are available in your market and models the incremental revenue they would add to your BESS business case.

No, and in many cases it makes sense to phase them separately. A common approach is to install the chargers first — operating within your existing grid capacity using smart load management — and add battery storage in a second phase once you have 6 to 12 months of real operational data on your actual load profile and charging patterns. This real data often produces a more accurate BESS sizing and dispatch design than a purely theoretical model. The main consideration is ensuring that your electrical infrastructure is designed from the outset to accommodate future battery integration — specifically that your switchgear and inverter space allocation allow for it — so that the second-phase installation does not require significant rework.