People use "energy aggregator" to mean either:
- Energy broker: Energy brokers find a new electricity contract or renew an existing one, so you can get a better rate
- Flexibility aggregator: A flexibility aggregator connects businesses to income from flexibility markets by changing when their batteries, EV chargers or other controllable equipment use, store or export power.
This article explains how flexibility aggregators give your commercial battery a route into wholesale electricity trading without you having to manage the trading yourself.
What an energy aggregator is
An energy aggregator uses software to control distributed energy resources (DER) across a range of commercial sites. DERs are electrical equipment such as batteries, heat pumps and cold-store compressors.
Companies need energy aggregators because the equipment they have onsite may not offer enough controllable power to trade on its own. In some cases, a firm may have enough, but the cost, data requirements and trading work make direct trading impractical.
When an aggregator joins multiple sites together, it can create a large enough pool of flexible power to measure, trade and pay out against.
Definition: In the wholesale electricity market, flexible power means stored electricity or electricity use that can be moved, reduced or sent to the grid when needed.
Your battery remains on your site, and the aggregator can only use the spare battery capacity you agree to make available.
In practice, an energy aggregator does two main jobs:
- Connects to your battery or other controllable equipment through software
- Handle the trading rules, live data and reporting needed to trade
Note: An aggregator does not make every battery suitable for trading. Some batteries are too small, too hard to control, or too important to site operations.
Energy aggregators vs energy brokers
The differences between energy brokers and energy aggregators are:
| Energy broker | Flexibility aggregator | |
|---|---|---|
| What it does | Finds or renews your electricity contract | Connects your battery or controllable equipment to flexibility or trading markets |
| Works on | The unit rate, standing charge and contract terms for the power you buy | The spare battery capacity or flexible equipment your site can make available |
| Best for | Reducing the price you pay for electricity | Earning from battery use, EV charging, heating, cooling or other controllable demand |
Rules of thumb:
- Use a broker: when you want to compare, renew or switch your electricity contract
- Use an energy aggregator: when you have a battery, EV charger or other controllable equipment that could earn from flexibility markets by changing when it uses, stores or exports power
- Use both: when you want a better price for the electricity you buy and a route into flexibility markets for the battery or equipment your site can offer
Why a commercial battery needs an aggregator
A commercial battery can store power when prices are low and use it later to reduce electricity bills when grid power costs more. If your site can also export, you may be able to sell stored power into the GB wholesale market when prices rise.
The problem is that direct trading in the wholesale market requires:
- Enough power volume to make the trade worthwhile (even 500 kWh battery energy storage system, or BESS, may need a trading partner)
- Half-hourly settlement data showing what your site used or exported
- Battery controls that can follow charge and discharge instructions
- A contract that allows trading
- Enough export capacity if the battery sends power back to the grid
- The trading systems, registration and reporting needed to take part
That is why many commercial battery storage setups need an aggregator.
Instead of managing the market yourself, your battery joins other sites in a larger trading group. The aggregator handles the market rules, data, reporting and charge or discharge instructions needed for trading. When an aggregator controls many sites as one group, you may hear this called a virtual power plant.
| Route | What it means |
|---|---|
| Trading on your own | Your site would need to handle the market rules, data, trading systems and reporting itself |
| Trading through an aggregator | The aggregator handles the trading work and includes your battery in a larger group of sites |
Note: In Great Britain, P415 opened a route for independent aggregators to trade flexibility from equipment on a customer’s site. This is often called behind-the-meter flexibility. Whether your battery can use this route depends on your meter data, battery controls, export limit, contract terms and revenue share.
What an aggregator can work with
An aggregator can work with equipment that can change when it uses, stores or exports power:
- Battery storage, which can charge or discharge when the control system instructs it
- EV charging, where charging speed can rise or fall as long as drivers still get the charge they need
- Heat pumps, which can warm or cool a building earlier, then use less power while the building stays comfortable
- Solar PV, which adds flexibility when paired with storage or export control
- Flexible loads, such as pumps or cold stores, where some running time can shift without harming operations
Together, these can form a controllable portfolio. That means a group of batteries, chargers and other equipment the aggregator can adjust within agreed limits.
Not every piece of equipment is useful all the time. It has to change when it uses power without harming comfort, production, charging availability or day-to-day operations.
Demand side response is the broader idea behind this. It means changing site electricity use to support the grid. A site may use less power for a short time, use power at a different time, or use a battery instead of drawing power from the grid.
How aggregation works in practice
Aggregation starts by checking how much battery capacity your site can make available, when the aggregator can use it, and what charge must be kept back for your own operations.
To work that out, the aggregator needs a live data link to your battery or battery controller. It also needs to know your normal electricity use, your likely demand, any solar generation and the limits you have agreed.
When the aggregator has your limits, this is how the process works:
- Data connection: The aggregator needs a live link to the battery or controller so it can see what is happening
- Normal use: It works out your baseline, which is what your site would normally do without trading activity
- Forecast: It looks ahead at likely site demand, solar generation, battery charge and market prices
- Trading instruction: When prices or market conditions make trading worthwhile, the system tells the battery to charge or discharge. This is often called a dispatch instruction.
- Site limits: The instruction must stay inside your site constraints and battery control limits. These rules cover how much battery capacity the aggregator can use, when it can use it, what charge your site must keep back, who can override an instruction, and what happens if the battery is not available.
- Reporting: The system records what happened, usually in half-hour periods. Your report shows what the battery did and what it earned.
How you save or get paid
What you earn depends on how the battery trades and what prices do. It is not a fixed return.
A commercial battery can create value in two broad ways.
- Energy arbitrage: The battery charges when power is cheaper and discharges when grid power costs more. This reduces your electricity bill.
- Trading income: If your battery is suitable for trading, an aggregator can trade spare capacity on your behalf. You and the aggregator then split the income through an agreed revenue share.
Some trading income depends on the baseline mentioned earlier. If the battery charges, discharges or avoids charging at a more valuable time, that difference may create income.
Export trading is another route. This means selling spare stored energy back to the market when the price is high enough.
For example, one installer presentation showed around £5,710 in annualised trading revenue from one site under current settlement rules. It assumed an 18p tariff, a 10p export rate and similar trading sessions for about half the year.
Treat that as an example of how the mechanism can pay. It is not a forecast for every battery.
Getting the best energy aggregator deal
Before you sign, check how the deal works in practice. The best offer is not always the one with the highest headline revenue share. It should also explain who controls the battery, what limits protect your site, and how payment is worked out.
Make sure any offer you consider contains:
- How long the contract runs, whether it is exclusive, and how you can leave the contract
- How you and the operator share revenue
- What fees or deductions come out before you share revenue
- Whether you need to switch supplier, or keep the one you have
- What limits stop the battery being cycled harder than the warranty allows
- What charge limits, discharge limits or reserve levels the agreement sets
- Who can override a charge or discharge instruction if you need the battery on site
- When you get paid, and what happens if you dispute a statement
- Who owns and can access your site data
- What reporting you get, and how often
- Which site constraints and priorities the operator must respect
These answers show who controls the battery, what the aggregator can do, and how the income is worked out.
How GridVolt connects your battery to the market
GridVolt helps compatible GB battery sites take part in wholesale trading through our energy aggregator software, GridTrade. Partner with us and you can keep your battery and your energy supplier, if you want.
In addition, Energy Manager can reduce your site’s energy costs by charging your battery when power is cheaper and using it to power your site when grid electricity costs more.
Tell us about your battery, tariff and site load, and we'll review your setup and show whether GridTrade or Energy Manager is the better fit.
Frequently asked question
Energy aggregator vs virtual power plant
You will often see these terms together, but they are not the same.
A virtual power plant, or VPP, is a group of batteries and other flexible assets that work together as if they were one power station.
An energy aggregator is the operator that manages the group's market activity. It connects to the assets, follows the agreed limits, sends instructions and reports the result.
In many cases, your battery may form part of a wider virtual power plant. The aggregator manages the trading work for that group.