Behind the meter refers to the electrical equipment that’s connected to your side of the electricity meter. This on-site equipment can lower your energy bills and, in some cases, return money to you through energy trading.
In this guide, learn what impact behind the meter equipment has for commercial sites in both Great Britain and Ireland. Plus, find out how behind the meter differs from front of the meter, and how to maximise energy savings from your battery.
What is behind the meter?
The electricity meter is the boundary between your site and the public grid. Equipment connected on your side (the site side) of a meter is called “behind the meter”. This is equipment that can generate, store, control or use electricity on your site.
Examples of behind the meter equipment include:
- On-site solar generates electricity that the site can use straight away or store in a battery.
- Battery storage charges from cheap grid power or solar power generated at your site. It can then use this stored electricity to provide power to your site when grid electricity costs more. Battery storage is at the heart of most commercial battery storage projects.
- EV chargers draw a lot of power at once when in use. Firms can use stored battery power to cover some of this extra demand and avoid paying for a larger grid connection.
- Energy management software decides when connected equipment should generate, store or use electricity.
- Combined heat and power makes electricity and useful heat from the same fuel. For example, a gas engine can power the site while heat from the engine warms the building or its water.
- A microgrid links the site’s solar, battery and electricity use through one local network.
When your site buys electricity from the grid, the power crosses the meter as it enters your premises. The meter then records this as an import, which appears on your electricity bill.
Power can also travel the other way. If your site sends spare electricity to the grid, the meter records it as an export. Your supplier may pay you for that exported electricity. In some Great Britain arrangements, your battery may also earn income from energy trading
What a behind-the-meter battery does for your site
A behind-the-meter battery has two main functions:
- Charging with cheaper grid electricity or solar power generated on site
- Discharging to provide power to a site when grid electricity is expensive
The battery’s storage capacity determines how much electricity it can hold while its power rating determines how quickly it can charge or supply power.
The problem with fixed schedules
Many commercial batteries follow the fixed schedule set when they were installed. Their control software keeps following that schedule even when electricity prices, solar output or site demand change.
This can make the battery charge or discharge at the wrong time. For example, it may use up its stored power before the site needs it most.
How active optimisation solves this
Battery software with active optimisation works differently. It sets the battery’s charge and discharge cycles according to:
- How much electricity the site has been using, and how much it expects to use
- How much electricity its solar panels are likely to make
- The site's tariff and how prices change through the day
- The battery's charge level, plus the limits that keep some power in reserve and keep the battery safe
The software may charge the battery when electricity is cheapest. It can then keep enough charge for the times when the site uses more power and grid electricity costs more. Reducing these peaks is called peak shaving.
Can a behind-the-meter battery earn from the market?
In Great Britain, a battery may earn extra income from the wholesale electricity market. This is where generators, suppliers and traders buy and sell electricity before suppliers sell it to customers.
The battery still serves your site first. You agree how much of its capacity your trading provider may use. This keeps enough charge available for your site and any battery reserve you have set.
It may be that your commercial battery is too small to make trading worthwhile on its own. Energy aggregators solve this problem by grouping batteries from several sites into one larger trading pool. These pools are often called virtual power plants in the UK.
How does a battery earn trading income?
Your aggregator can change how much electricity your site takes from the grid or sends back to it.
For example, it may tell the battery to:
- Power your site so you buy less electricity from the grid
- Pause charging if the grid needs more power
- Send stored electricity back to the grid, if your export setup allows it
The aggregator sells a planned change in grid use through the wholesale market. It then sends instructions to the batteries in its group so they can deliver that change.
After the trading period, the aggregator checks how much of that promised change the batteries delivered.
First, its software estimates how much electricity your site would normally have imported or exported. This estimate is called a baseline.
For example, the aggregator’s software may estimate that your site would normally import 50 kWh while charging the battery. If the aggregator pauses charging and the site imports only 10 kWh, the instruction reduces imports by 40 kWh.
The meter readings confirm that the site delivered 40 kWh of the promised change. The aggregator receives payment based on the amount delivered.
The aggregator then pays the site under its agreed contract, usually after taking its fee or share of the trading income. Payment methods and timing vary between providers.
What does your battery need before it can trade?
Before your battery can trade, the provider will usually check:
- Half-hourly meter: Records how much electricity the site imports and exports
- Compatible controls: Let the trading software tell the battery when to charge or discharge
- Export permission: Needed if the battery will send electricity back to the grid. It also sets the maximum amount the site may export at once
- Electricity setup: The contract, meter and settlement setup must work with the trading route
- Suitable battery: The aggregator must be able to control it and add it to its trading pool
Is a behind-the-meter battery right for your site?
Whether a behind-the-meter battery is right for your site depends on your electricity use, tariff, available space and what you need the battery to do.
If you are considering a battery
Work out the possible savings using:
- your electricity tariff
- your half-hourly electricity use
- the proposed battery size
- any solar generation on site
- the times when your site uses the most electricity
This gives you a firmer financial basis for deciding whether to buy the battery.
If you already own a battery
You should review:
- its current charging and discharging schedule
- whether its charging schedule matches your tariff and site demand
- how much electricity it stores and supplies
- whether it holds enough charge for your busiest periods
- whether changing the schedule could reduce more of your bill
Use your half-hourly meter readings and battery data to compare what the battery does now with what it could do under a different schedule.
How GridVolt controls your battery
GridVolt's Energy Manager helps compatible commercial batteries respond to changing electricity prices, solar output and site demand.
GridVolt adds an on-site controller that sends charge and discharge instructions to the battery. If your existing equipment is compatible, you do not need to replace it. The controller costs £500 to £1,000.
How better battery control improved one client’s savings
In a live GridVolt deployment, better control improved the battery’s savings by 41% over 70 days.
To show what that means, imagine a £1,000 electricity bill. If the battery previously saved £100, a 41% improvement would increase that saving to £141. The full bill would not fall by 41%.
The result came from changing how the battery was controlled. It does not guarantee the same saving for another site.
Wholesale trading with GridTrade in Great Britain
For eligible sites in Great Britain, GridTrade can use an agreed amount of battery capacity for wholesale market trading.
The site keeps the charge it needs for its own use and any battery reserve. GridTrade uses only the capacity the site has agreed to make available.
GridTrade currently covers Great Britain only. In Ireland, Energy Manager can still reduce your bills by changing when the battery charges and supplies the site.
Talk to GridVolt about your tariff, half-hourly electricity use, solar generation and battery. GridVolt can review how an existing battery is controlled or help you assess how a proposed battery could perform on your site.
Note: As a rule, GridVolt does not combine GridTrade with wholesale-linked tariff optimisation on the same battery. Because the price you pay changes with the market, the battery may already charge and discharge at different times. This makes it harder to separate what the battery did because of the tariff from what it did because of GridTrade.