How much more can a commercial battery save with optimisation software than with fixed inverter schedules?

No standard percentage applies to every commercial battery. The extra saving depends on:

• How and when the client uses electricity
• The client’s tariff
• Solar generation
• The battery’s power and usable capacity
• What the inverter controller already does

At one live GridVolt deployment, GridVolt recorded 41% more battery savings during the first 70 days. Treat this as one site result, not as a percentage to use in every proposal.

Do not simply add 41% to the client’s estimated electricity bill saving. Instead, model the same battery twice using the same site data:

1. Show the battery with fixed inverter schedules.
2. Show the same battery with optimisation software added.

The useful figure is the extra annual battery saving after deducting all EMS costs.

What did the GridVolt comparison show?

At the GridVolt agricultural deployment, the battery had previously followed fixed inverter schedules.

Energy Manager then used the client’s actual tariff and updated forecasts of electricity demand and solar generation. The software recalculated the battery schedule every 15 minutes.

During the first 70 days, GridVolt recorded a 41% increase in battery savings. Most of the extra saving came from avoiding Distribution Use of System, or DUoS, charges and Capacity Market Obligation charges that the client had continued to pay under the previous fixed schedule.

The 41% increase applied to the saving from the battery, not to the client’s whole electricity bill.

For example, if fixed schedules save the client £10,000 a year, a 41% increase would raise the battery saving to £14,100. The optimisation software would add £4,100 to the saving. It would not reduce the client’s total electricity bill by 41%.

Why the improvement changes between sites

Optimisation software will not produce the same extra saving for every client. The result depends on what happens at the premises and how well the existing inverter controls already manage the battery.

Check the following points:

• Changes in electricity use: Fixed schedules work best when the client uses electricity at similar times each day. If the period of highest demand changes, the battery may discharge too early or fail to cover the peak.
• The tariff: Fixed inverter settings can often cover a simple day-and-night tariff. DUoS periods, Capacity Market Obligation charges, and changing import prices give the software more tariff periods and charges to account for when it calculates the battery schedule.
• The timing of solar generation and demand peaks: When solar generation and electricity use vary, the software must calculate when to charge the battery, keep energy in reserve, or discharge it.
• Battery power and capacity: The battery needs enough power, measured in kilowatts or kW, to reduce the peak. It also needs enough usable capacity, measured in kilowatt-hours or kWh, to continue discharging through the expensive period.
• The existing inverter controls: If the inverter already manages peak shaving, solar charging, and tariff times well, the client may gain less from adding a separate EMS.
• The quality of the forecasts: Forecast-led control needs reliable information about electricity demand, solar generation, and tariff prices. Poor information may prevent the software from improving on a fixed schedule.
• Battery losses and wear: Every charge and discharge loses some electricity and adds wear to the battery. The software should not schedule a cycle when the likely saving will not cover those costs.
• EMS costs: The controller, software, commissioning, support, and maintenance costs all reduce the client’s final saving.

Fixed schedules can work well when the client uses electricity in a similar way at the same times on most days. For example, a simple inverter schedule may cover a battery that charges overnight and discharges during a predictable afternoon peak.

Optimisation software may add more saving than a fixed schedule when the client’s electricity use changes through the week. The software may calculate that the battery should:

• Keep energy for a later demand peak
• Avoid discharging before the solar panels start producing more electricity
• Charge before a tariff change
• Keep the client’s agreed minimum reserve in the battery

For a proper estimate, use the client’s own half-hourly or 15-minute electricity data. Compare the same battery under fixed and optimised control using the same tariff, solar generation, reserve setting, and equipment limits.

Then show the extra annual battery saving after deducting every EMS cost, rather than using the percentage from one case study as the standard result for other clients.

Related questions

When is it worth adding a separate EMS to a commercial battery?

When is an inverter’s built-in schedule good enough for a commercial battery?

How do I prove the battery savings after installation?