The commercial battery you invested in for your site may work exactly to the manufacturer’s specification, but you’re not seeing the savings promised to you when the electricity bill arrives.
The reason for this is most likely to be the energy optimisation software you’re using. By charging and discharging your battery to a fixed schedule, as many systems do, you miss out on cheaper times to charge and better times to use the electricity it has stored.
If you want to improve the performance of your current setup, or you’re planning a brand new commercial battery storage setup for your site, read on to find out why some projects fail and how to prevent that from happening to you.
What is energy storage optimisation?
Energy storage optimisation is making the most efficient use of your on-site battery to reduce what your business spends on electricity.
Energy optimisation software uses information on your tariff, expected power demand, solar generation forecasts and current battery levels to decide when to charge the battery, use the electricity stored in it or keep that electricity for later.
The aim isn’t to constantly use your battery, because, in some circumstances, like when grid electricity will cost more later or your solar panels are expected to generate spare power, you save money.
That’s because keeping electricity in the battery until prices rise or leaving room to store solar power may save you more than using the battery straight away.
Note: Charging when grid electricity is cheaper and using that electricity when prices rise is called energy arbitrage.
Why fixed battery control can leave money on the table
A battery can only follow the instructions it receives. If it’s set to charge and discharge at the same times every day, it can’t respond when electricity prices, site demand or solar generation change.
This can leave you buying expensive grid electricity while there’s cheaper electricity that you’re not using in the battery. It can also fill the battery before your solar panels start generating or use stored electricity before you reach the most expensive part of the day.
These are the most common signs we see when a business first gets in touch:
| What you see | What it may mean |
|---|---|
| The battery is empty before the periods you pay the most for grid electricity | It could be supplying electricity to your site too early, and should be keeping power back for the most expensive periods. |
| The battery is full while your solar panels send electricity to the grid. | The battery may have charged too soon, leaving no room for solar electricity you could have stored and used later. |
| The battery stays full when grid electricity is expensive or empty when it’s cheap. | Its charging and discharging times may not suit your tariff. |
| Your site still draws a lot of power from the grid even though the battery has electricity stored. | The battery may not be set to discharge then, or it may not be able to supply power quickly enough. |
| Part of the battery always remains unused. | It may be set to keep back more electricity for emergencies than your business now needs. |
| The battery charges and discharges regularly but saves little money. | The gap between the cheaper and more expensive price may be too small to cover the electricity lost during charging and discharging and other costs. |
| The battery is saving much less than forecast. | Electricity prices, the way your site uses power or the amount of solar you generate may have changed since the forecast was made. |
Why flexible battery control software can save you more money
Flexible battery control recalculates when your battery should charge, discharge or hold electricity as prices and conditions at your site change. To do that properly, knowing what electricity costs at different times of day isn’t enough.
The software also needs to know what’s happening across your site:
| What the software looks at | Why it matters |
|---|---|
| Your electricity use | The software needs to know how much electricity your site uses and when, so it can keep battery power for when you’ll need it most. Your main meter may not show all of this because your battery or solar panels can supply electricity behind the meter |
| Your electricity tariff | The software compares what it costs to charge the battery with what you could save by using that electricity later. This matters on a time-of-use tariff because electricity costs more at some times than others. |
| Your solar panels | Knowing when your panels are likely to generate electricity helps the software leave enough room in the battery to store it. |
| Your battery capabilities | The software needs to know how full the battery is, how much it can hold and how quickly it can charge or supply your site. |
| Electricity kept in reserve | You can tell the software how much electricity to keep back for emergencies or other needs. It won’t use that amount to cut your bills or earn trading income. |
| Electricity losses and other costs | Some electricity is lost whenever the battery charges and discharges. The software can avoid charging or discharging it when the likely saving is too small to make it worthwhile. |
| Your site’s limits | The software must stay within the limits on how much power your site and equipment can take from or send to the grid. |
How does flexible battery control software work out when to charge and discharge?
The software constantly references information it takes from your electricity tariff, expected site demand, solar forecast and battery charge level. It uses this to compare how much it costs to charge the battery with what the savings might be if you used that electricity at a different time.
Here’s an example of how it works.
Let’s say your battery charges up with 100 kWh of grid electricity at 10p per kWh, and that costs £10. For this example, we’ll assume that 10% is lost during charging and discharging, leaving 90 kWh for your site to use later.
If your site uses that 90 kWh when grid electricity costs 25p per kWh, the battery saves you from buying £22.50 of electricity from the grid. Take away the £10 charging cost and the gross saving is £12.50 before fees and other costs.
If grid electricity costs only 12p later, buying the same 90 kWh from the grid would cost £10.80. After taking away the £10 charging cost, only 80p remains before fees and other costs. At that price, charging the battery may not have been worthwhile because those costs could easily wipe out the 80p.
The software repeats this calculation throughout the day using the latest information. If a different charging or discharging time would now save you more, it updates its instructions.
Could GridVolt help you get more from your existing battery?
GridVolt’s proprietary software can check how well your commercial battery is performing and whether it’s delivering maximum savings to your company.
Let us have your half-hourly data from the past 12 months. We’ll then compare what your battery actually saved with what it could have saved using different charging and discharging times.
It’s this software that powers Energy Manager. Use it with existing batteries on your site to put those better times into practice and keep updating them every 15 minutes.
It works. At one agricultural site, Energy Manager increased the savings made by the battery by 41% during its first 70 days. The improvement came from better forecasting, tariff planning and charging and discharging times. Results vary between sites.
For suitable businesses in Great Britain, we can also check whether a compatible battery could earn trading income through GridTrade.
Fill out the form on the right or contact GridVolt to discuss your site.
Energy storage optimisation FAQs
Can battery optimisation work without solar panels?
Yes. You don’t need solar panels to benefit from battery optimisation. Your battery can charge from the grid when electricity is cheaper and supply your site when it costs more. If you have solar battery storage, the software can also leave room in the battery for solar electricity you don’t use straight away.
Will battery optimisation work with my existing battery?
Often, yes. GridVolt first needs to check that its controller can connect to your battery and inverter and that both can follow its instructions. It also needs to keep charging and discharging within the equipment and warranty limits. If everything is compatible, you won’t need to replace your battery.
How often should the software update charging and discharging times?
There isn’t one right answer for every battery. The software needs to recalculate often enough to keep up with changes in electricity prices, your site’s power use, expected solar output and the amount stored in the battery. GridVolt Energy Manager does this every 15 minutes.
How are energy monitoring, energy management and energy storage optimisation different?
Energy monitoring software shows you what has already happened at your site. Energy management software goes a step further by using that information to work out how connected equipment should run and sending instructions to it. Energy storage optimisation does this specifically for your battery.
How are energy storage optimisation software, a BMS and a BESS different?
A battery energy storage system, or BESS, is the complete setup. It includes the battery, inverter, controls, safety equipment and meters.
The battery management system, or BMS, looks after the battery itself. It monitors the cells and stops the battery operating outside its safety limits.
Energy storage optimisation software has a separate job. It works out when the battery should charge, supply your site or keep its electricity for later.