Battery energy trading via P415 lets companies earn income from price changes in the electricity market. It adds a trading layer on top of the savings your battery already delivers. It does this in two ways:
- By exporting stored electricity when market prices are high
- By changing when the battery charges or discharges, if that change has value in the market
In this article, find out what P415 is, what it changed, how it works, and where the returns are in battery trading.
What is P415?
P415 is the mechanism independent aggregators use to sell their clients’ battery flexibility into the wholesale energy market. Battery flexibility is the ability to change when your battery imports, stores or exports electricity.
Before that, firms could only access the wholesale market via their electricity supplier. Most didn’t offer this service as they had no setup to manage trading, settlement and imbalance risk for behind-the-meter batteries.
Ofgem approved this Balancing and Settlement Code modification on 6 October 2023. It went live when Elexon implemented it on 7 November 2024 as part of the November 2024 BSC Standard Release.
Definition: Behind-the-meter batteries are batteries on your side of the electricity meter. They store electricity for that business to use, export or trade, rather than acting as a part of the national grid.
Aggregators and Virtual Trading Parties, and how they work together
There are two parties in battery trading - an aggregator and a Virtual Trading Party (VTP). Aggregators manage your on-site battery. VTPs, a role created by the P415 rule, are approved market participants that carry out your wholesale trades for you.
In some cases, aggregators and VTPs are the same company. In others, aggregators work as trading partners with VTPs.
Either way, the benefit to you is that you don't need to learn and execute trading yourself. Your aggregator handles that for you.
What do VTPs actually trade?
A Virtual Trading Party trades deviations, or changes from your site’s normal pattern of electricity usage. You may hear this referred to as your “baseline”.
In lay terms, let’s say your battery normally pulls 100 units of electricity from the grid at one in the morning. As this is your standard behavior, it becomes the baseline for a trade.
On one night at the same time, your trading provider notices wholesale electricity is more expensive than usual. It tells your battery not to charge. This means your site has imported 100 fewer units than its baseline showed. That missing demand is the deviation.
In the electricity market, that deviation has value because your site used less power than normal at a costly time. The market now has 100 units of demand it no longer has to cover.
Your VTP can trade the value of that reduction in the wholesale market. Market buyers pay the VTP through the trading process. You then get your agreed share through your contract with the trading provider.
The same idea can work the other way.
For example, your site may normally export very little at 6pm. But if wholesale prices are high, your trading provider may tell the battery to send stored electricity to the grid.
Your site now exports more electricity than its baseline showed. That extra export is also a deviation.
The VTP can trade that extra export value in the wholesale market. You then get your agreed share through your trading agreement.
What decides whether P415 trading is worth it?
A site battery already has a job before P415 trading is added. It stores cheaper power and uses it later to cut how much expensive grid electricity your site has to buy.
That might mean discharging at 5pm, when your tariff is higher. It might also mean keeping stored power back for EV charging or backup.
A P415 trade only makes sense if it beats that existing site value.
When it shouldn't trade
Let’s say your battery normally discharges at 5pm to avoid buying electricity at a peak rate of 25p per unit. Your VTP then spots a trading opportunity at 4pm. It could export that stored electricity to the grid and earn 18p per unit.
On paper, that looks like good business. The problem is that if the battery exports at 4pm, it will not have that same electricity available at 5pm. Your site would then have to buy power from the grid at 25p per unit.
So the trade would earn 18p, but it would cost the site a 25p saving. That leaves the business 7p worse off per unit.
In that case, the VTP should not trade. The battery is more valuable doing its normal site job.
When it should trade
Using the same example, the VTP spots a wholesale trading opportunity at 4pm worth 32p per unit. If the battery exports at 4pm, the site loses the 25p saving it would have made at 5pm.
But the trade earns 32p. That leaves the business 7p better off per unit.
In that case, the VTP should trade. The battery creates more value by exporting to the grid than it would have created by serving the site later.
The basic commercial test
That is the basic commercial test behind P415 battery trading. The trade only works if it beats the battery’s next best use.
Control counts in P415 trades. A good trading setup should not send the battery into every market opportunity. It should check whether the site needs that stored power first.
Note: These examples are simplified and don’t take into account battery returns and wear in their calculations. Check out our energy arbitrage article for more information.
What affects the value of P415 trading?
Two sites can have similar battery setups yet earn very different amounts from P415 trading. These factors directly impact your income:
| Factor | Why it matters |
|---|---|
| Site tariff | If your site pays a high rate at certain times, the battery may save more by powering the site than by trading. |
| Battery size | A larger battery can create more trading value, but only if it has stored power available at the right time. |
| Normal charge and discharge pattern | If the battery is already busy saving the site money, it may have less spare capacity for trading. |
| Export limit | If your site has a low export limit, the battery cannot always send as much power to the grid as the market wants. |
| Site load profile | Your site load is how much electricity your site uses at different times. A stable site load makes deviations easier to measure. A more changeable load can make trading harder to model. |
| Wholesale price | A trade only works if the market price beats the value of using the battery on site. |
| EV charging or site constraints | If the battery is needed for chargers, backup, or operations, that capacity may need to stay on site. |
| Battery cycling and warranty | Extra trading can add more charge and discharge cycles. Those trades need to earn enough to justify the extra battery use. |
Before you try to forecast potential income from P415 trading, run a battery health review. This shows what the battery does now, how much it already saves you, and whether trading would add more value.
Is your business a good fit for P415?
P415 trading is not right for every site with commercial battery storage. It is worthy of consideration however if you meet most of these criteria:
- A GB location: P415 is only available in Great Britain, not Northern Ireland or the Republic of Ireland.
- A half-hourly meter: Your site needs a meter that records electricity use every half hour. This gives the trading provider the data it needs to measure changes in your site’s electricity use.
- A commercial-size battery: P415 trading usually makes more sense for batteries around 100 kWh or larger. Smaller batteries may not store enough power to make the trading income worth the setup and management viable.
- A compatible battery and inverter: The trading provider needs to connect to your battery. If it cannot see and control the battery safely, it cannot trade it.
- Spare battery capacity: Your battery needs stored power it can use for trading without leaving the site short later. If the site needs that power for peak pricing, EV charging, or backup, the trade may not be worth it.
- A recent battery review: If you bought your battery before P415 went live, the original payback case may not include trading income.
If your site meets most of these checks, P415 may be worth a closer look, depending on how much your battery setup currently saves you.
What should you ask a P415 trading provider?
If you believe your site might be a good fit, your first step should be to contact a VTP or aggregator.
Before you sign up, ask the following questions:
| Question | Good answer | Red flag |
|---|---|---|
| Who will carry out the trade? | “We do it,” or “We work with this named trading partner.” | They cannot tell you who actually makes the trade. |
| Can you work with my battery? | “We will check your battery and inverter first.” | The sales pitch leads on income and comes nowhere near your equipment till the end. |
| What data do you need from me? | “We need your meter data, tariff, battery details and current settings.” | You get a savings figure before they ask for your site details. |
| How do you decide when to trade? | “We compare the trade with what the battery would save on site.” | They always trade when wholesale prices are high, even if your site would save more by using that stored power later. |
| What site needs come first? | “We ask when your site needs the stored power first. That could be expensive tariff periods, EV charging or backup. We only trade when the battery can spare it.” | They cannot explain when the battery will be held back. |
| How do you measure what the battery already saves? | “We check current savings before adding trading income.” | They only talk about new trading income. |
| How do you stop the same value being counted twice? | “We show site savings and trading income separately.” | They add every possible saving together without showing trade-offs. |
| How do you protect the battery? | “We explain how trading affects cycles, warranty and battery use.” | They brush off battery wear. |
| How will I see the results? | “You will see what the battery saved, what it earned and when it did not trade.” | They only show one total income number. |
| How do I get paid? | “Your contract shows your share, when you get paid and what costs come out first.” | They cannot explain how the money reaches you. |
| What happens if P415 rules change? | “We show which figures depend on today’s rules.” | They present today’s income as a fixed future return. |
Why the software your battery uses matters in P415 trading
Successful P415 trading depends on the quality of controlling software as much as your battery setup.
Basing its actions on the wholesale price alone is not enough. The software needs to know your tariff, how full the battery is, how much power the site needs, and whether EV chargers need power later. It also needs to know any export limits.
Sometimes, the best decision is to trade. At other times, it is better to power the site or wait for market conditions to change. Without that level of data and intelligence, it will frequently make the wrong move. For example, it might export power at 4pm, then leave the site buying expensive grid electricity at 5pm. It might chase trading income and miss a better saving on site.
GridTrade is GridVolt’s battery trading service for suitable GB sites. It adds the P415 trading layer to compatible commercial batteries, without asking you to change supplier or replace the battery. It connects through GridVolt’s on-site Energy Manager, so the battery can be controlled around your site needs as well as market prices.
Already have a commercial battery? Ask GridVolt for a battery health review. We’ll help you see what the battery does now, what it already saves, and whether GridTrade could add more value through P415.