Commercial batteries store electricity and release it later for use on site or to sell back to the grid. They’re not the only way to reduce how much you import from the grid. By changing when you use your on-site equipment, you can reduce the amount of power you buy during the most expensive parts of the day.
Cold stores, hot water systems, chillers and EV chargers can all use electricity at different times without stopping your site from operating normally. This can save or earn money in two ways:
- Use more electricity when it is cheaper and less when it is expensive
- Get paid to reduce or delay electricity use for a short period when the grid needs it
In this article, we’ll explore the “alternative energy storage systems” you might already have and show how they can help lower utility bills and earn trading income.
How can equipment earn money from energy trading?
Sometimes, homes and businesses need a lot of electricity at the same time. That pushes electricity prices up and, to relieve pressure, energy companies look to businesses to help them.
That doesn’t mean you have to power down your site and its assets. It may only mean turning down or pausing equipment such as refrigeration, water heating, air conditioning or EV chargers for a short period. Any change must still keep food cold, provide enough hot water, keep rooms comfortable and leave vehicles ready when needed.
Trading providers can do this work for you.
Read on to discover four ways to use equipment you already own to cut electricity costs and earn trading income.
The alternative energy storage systems you may already have on site
Below, find the assets and equipment that you may already have on site that you can save money on by changing when they draw power from the grid.
For each one, we’ve provided an example saving. To make the examples easy to compare, we’ve used a simple electricity price difference on a site with no solar or battery. We have assumed the site pays 30p/kWh during peak periods and 16p/kWh at cheaper times, giving a 14p/kWh difference for each kWh of electricity use avoided during the peak window.
Note: Using that assumption, every 10 kWh avoided during the peak period is worth about £1.40. We have not accounted for VAT, standing charges or any software and service costs. What you actually save will depend on your tariff, site load, equipment settings, and whether you have solar or battery storage.
1. Cold rooms, fridges and freezers
It’s worth checking your cold rooms, fridges and freezers first because they use a lot of electricity.
Cold rooms usually work within a temperature band rather than at one exact temperature. The saving comes from doing more cooling before the peak-rate period starts, bringing the room closer to the lower end of its approved range. The compressors then have less work to do when electricity is more expensive.
Accurate control is important here because you must still prioritise food safety rules. In England, Wales and Northern Ireland, chilled food must be kept at 8°C or below. Many operators set fridges lower than that, often around 5°C or below, to keep a safety margin.
How a cold store can cut costs and earn trading income
Let’s say you have a 100,000 m³ cold store. Using the Cold Chain Federation benchmark of 10 kWh/m³/year, its refrigeration system would use about 1,000,000 kWh a year.
You could cool the store a little more while electricity is cheaper, then turn down some of the refrigeration equipment during a more expensive period while keeping the temperature within safe limits.
If you moved 1% of the cold store’s annual electricity use from expensive periods to cheaper ones, 10,000 kWh would go onto the cheaper rate. At a 14p/kWh difference, this would save you £1,400 before costs.
The same cold store could also earn trading income. Suppose it would normally use 100 kWh during a particular half-hour but, because it had already done more cooling, it used only 80 kWh. That is a 20 kWh reduction. At an agreed payment of 30p/kWh, the site would receive £6 while still keeping the store at a safe temperature.
2. Hot water cylinders and thermal stores
Hot water cylinders and thermal stores hold heat in water. The saving opportunity is mainly on sites with an immersion heater, electric boiler, heat pump or electric top-ups, but not sites where most or all of the hot water comes from gas.
If your site has enough stored hot water to cover demand during peak-rate periods, you may be able to heat more of the water beforehand and use it later.
You need to heat the cylinder or thermal store before the peak-rate period starts, then reduce or delay electric heating when prices are higher. Be aware of hygiene rules when doing this. HSE guidance says hot water should be stored at 60°C or higher, and should reach 50°C at outlets within one minute, or 55°C in healthcare premises.
How hot water can cut costs and earn trading income
Let’s say that one of your sites has a 3,000-litre thermal store that’s heated by an immersion heater or electric boiler.
Heating 1,000 litres of water by 10°C takes about 11.6 kWh. That means raising the temperature of the full store by 10°C would use about 35 kWh of electricity.
You could do more of that heating while electricity is cheaper, then use the stored hot water when prices are higher. At a 14p/kWh difference between the cheap and peak rates, moving 35 kWh onto the cheaper rate would save £4.90 each time. Do that 250 times a year and the total saving would be around £1,225 before costs.
The same thermal store could also earn trading income. Suppose its electric heating would normally run during a particular half-hour. Because enough hot water has already been stored, the heating can be paused until that half-hour ends. You use less electricity during that period and can receive a payment for the reduction, while of course keeping the system at the temperatures required for hygiene.
3. Air conditioning, chillers and building temperature
Air conditioning and cooling costs can spike when the hottest and busiest parts of the day on a site overlap with the periods when electricity is at its most expensive. The savings here come from doing more of the cooling before the price rises and getting the system to use less power during peak-rate periods.
For example, on a hot day, you could cool the building slightly before the afternoon peak, while keeping rooms within agreed comfort limits. The building then starts the peak period at a lower temperature, so it takes longer for rooms to warm back up. That gives the cooling system more room to ease off while prices are highest.
Some buildings make this easier than others. If a site holds temperature well because of its insulation, layout or thermal mass, the cooling system has more room to ease back during peak-rate periods. If rooms warm up quickly, the savings may be small because comfort limits are reached too soon.
This isn’t the same as turning the cooling down and hoping your staff and visitors cope. Make sure that any pre-cooling or peak-period reduction keeps rooms within agreed comfort and ventilation limits, as recommended under HSE guidance.
How air conditioning and chillers can cut costs and earn trading income
According to analysis from the BRE, median annual electricity use for office cooling is 40.5 kWh/m². Let’s say one of your sites has a 5,000 m² air-conditioned office. This could mean annual cooling use of around 202,500 kWh.
You could cool the building a little more while electricity is cheaper, then turn down the air conditioning or chillers during the peak-rate period without allowing the rooms to become too warm for staff or visitors.
Suppose you moved 5% of the office’s annual cooling from the peak-rate period to cheaper hours. That would move 10,125 kWh onto the cheaper rate which, at a 14p/kWh difference, would save you about £1,418 before costs over a year.
You could also earn trading income by turning the cooling down for an agreed half-hour and getting paid for the drop in electricity use. This works best in buildings that stay cool for longer.
4. EV chargers and parked vehicles
Save money on EV chargers by moving charging to off-peak periods. The vehicles just need enough charge for the next shift. They don’t care whether the electricity was bought at 16p or 30p.
For example, in a delivery business, a shift may start at 7am and end at 6pm. When drivers leave work at 6pm, they plug in their vehicles. By restricting charging to cheaper overnight periods, you save money and the vehicles are still ready for the next shift.
This works best for companies with depot vehicles, fleet cars, staff cars and long-stay parking. It’s less easy to control for sites where charging demand is around the clock, like hotels and hospitals.
How EV charging can cut costs and earn trading income
Let’s say your delivery firm has 10 vehicles that each need 30 kWh before the next morning, totalling 300 kWh of charging.
You could delay that charging until electricity is cheaper, provided every vehicle is still ready for the next shift. At a 14p/kWh difference between the peak and cheaper rates, moving all 300 kWh would save £42 each day the vehicles charge. If they charge on 250 working days a year, the total saving would be around £10,500 before costs.
You could also earn trading income by pausing some of the charging for an agreed half-hour and getting paid for the drop in electricity use. This works best when you know how long charging can stop without leaving any vehicle short of power for its next journey.
What actions you can take today
| Asset | Who to speak to and what to ask | What to calculate | Approve action if... |
|---|---|---|---|
| Cold rooms, fridges and freezers | Speak to the facilities manager, refrigeration contractor or energy manager. Ask for annual refrigeration kWh, peak-rate use, approved temperature range and alarm limits. | How much refrigeration use could move to a cheaper period and how much compressor use could reduce briefly during a trade | Your stock will always stay within its approved temperature range |
| Hot water cylinders and thermal stores | Speak to the facilities manager, M&E contractor or maintenance team. Ask how much electricity hot water uses, when it heats, and when demand is highest. | How much water heating could move to cheaper hours and how much electric reheating could be delayed during a trade | Hot water will still be available when the site needs it. |
| Air conditioning, chillers and building temperature | Speak to the facilities manager, HVAC contractor or BMS provider. Ask for cooling use, peak periods, comfort limits and occupancy patterns. | How much cooling could happen earlier and how much cooling power could reduce briefly during a trade use that could move out of peak-rate periods | Rooms and common areas will stay within agreed comfort and ventilation limits. |
| EV chargers and parked vehicles | Speak to the fleet manager, EV charging operator or facilities team. Ask when vehicles plug in, when they leave, and how much charge they need. | How much charging could move to cheaper hours and how much could pause during a trade | The vehicles you need will be ready on time |
Increase savings by pairing with a battery and/or solar
It’s possible to make meaningful savings by adjusting how and when you use your on-site electrical assets. Some of those assets may also earn trading income by briefly reducing or delaying their electricity use.
A battery gives your site another way to save and earn money. It can charge when electricity is cheaper and release that power later, when the site would otherwise need to buy electricity at a higher price.
The battery can also reduce how much electricity the site takes from the grid while the other equipment carries on working normally. For example, the air conditioning or EV chargers can keep running while the battery supplies some of the electricity they need.
This means the site may still be able to earn trading income without turning down the cooling, delaying water heating or pausing vehicle charging. The battery may also be able to send electricity back to the grid if the site is allowed to export.
If you have solar panels, the battery can store surplus solar power during the day and use it later. This reduces how much electricity the site needs to buy from the grid.
GridVolt’s Energy Manager controls your on-site battery to maximise savings based on electricity prices, how much power the site needs, how much solar power is available and the limits placed on the battery and grid connection.
Where trading is available, GridTrade can calculate whether the site could use this equipment, the battery or both to reduce electricity use for a short period without disrupting the business.
To find out more, fill in the form on the right or use our contact us page.