When a business buys a battery, they're buying flexibility-in-a-box. But that flexibility is only as good as the tariff it's paired with and the control system managing it.

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That was the core message of our recent webinar — The C&I Battery Playbook for Tariff Optimisation — which we ran together with Midsummer and Octopus Energy for Business. If you missed it (or want a refresher), the full recording is below.

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The session covered a lot of ground — from how time-of-use tariffs actually drive battery revenues, to EMS hardware decisions, to a live modelling walkthrough in Orkestra showing battery sizing, tariff optimisation, and revenue stacking on a real project.

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What struck us most was the volume and quality of questions from the audience. It's clear that the UK C&I battery market is maturing fast, and installers, developers, and energy consultants are moving past "should we add a battery?" to the much more interesting question: "how do we make this battery work as hard as possible?"

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So here's a summary of what we covered, followed by the best questions from the session with answers from our panel.

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The Three Pillars of a Great C&I Battery Project

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The webinar was structured around a simple framework. A C&I battery project is only as strong as the interplay between three things:

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1. The tariff. Time-of-use tariffs like Octopus Energy for Business's Shape Shifters range create the arbitrage opportunity — charging when electricity is cheap and discharging when it's expensive. Whether that's through set pricing bands (Trio) or half-hourly wholesale rates (Agile), the principle is the same. Without the right tariff structure, a battery is just an expensive box sitting in a plant room.

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2. The EMS (Energy Management System). The EMS is the brain that tells the battery what to do and when. Some are built into the inverter, others are external units. The choice depends on the inverter and battery hardware you're specifying — and it matters, because the EMS is what translates those tariff price signals into actual savings.

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3. The modelling. This is where it all comes together. You need to be able to model a specific site's load profile against real tariff structures, test different battery sizes, and stack the revenue streams — self-consumption savings, arbitrage, export, and potentially grid services — to build a compelling business case. That's what we demonstrated live in Orkestra during the session.

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Shape Shifters: What You Need to Know

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Fran Benson from Octopus Energy for Business walked through the Shape Shifters tariff range, and it generated a lot of questions. Here's the key context:

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Shape Shifters has been available to SME customers for some time and is now available to C&I customers. There are two products to be aware of:

• ‍Shape Shifters Trio - is already available nationally. It provides three time-of-use pricing bands — day, night, and peak — giving customers and their batteries a clear price spread to optimise against.‍
• Shape Shifters Agile - launches for C&I in June 2026. This exposes half-hourly wholesale pricing, creating even more granular optimisation opportunities. The Orkestra team have already uploaded the SME Agile tariff into the platform, so you can start modelling against it now.

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A few important points that came up:

• No battery size requirements. There's no minimum capacity needed to access Shape Shifters. Some SME businesses are already saving purely through having naturally off-peak demand profiles — no battery needed.
• Any battery/inverter brand works. Unlike Octopus's "Intelligent" tariffs (which require Kraken integration with specific hardware), Shape Shifters simply exposes price signals for your customer's EMS to respond to. That means it's hardware-agnostic.‍
• Day-ahead pricing via API. Pricing is shared the day ahead and available via API — making it straightforward to integrate with your customer's EMS for automated optimisation.

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The Orkestra team have already uploaded the Shape Shifters Agile tariff for SMEs into the platform, so you can start modelling against it now.

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EMS: Start with the Manufacturer

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Gus Pitfield from Midsummer covered the EMS landscape, and his advice was practical: start with your inverter and battery manufacturer's own EMS before going third-party.

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Most inverter brands have their own energy management systems, and they'll also have tested and approved third-party EMS units that integrate well. The key is ensuring compatibility — not every third-party EMS works with every inverter/battery combination, so check with the manufacturer first.

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For those looking at ancillary services (grid balancing revenue), the aggregator typically supplies a small piece of hardware that connects to the EMS. Again, this needs to be tested and approved for your specific hardware setup. But once it's in place, the aggregator's signals flow through the EMS to charge and discharge the battery for grid services revenue.

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And yes — an external EMS simply means a separate communications and management box that tells the inverter and battery what to do, as opposed to one that's built into the inverter itself.

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Modelling It All Together in Orkestra

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During the live demo, we walked through the full journey from opportunity to proposal — modelling a real project scenario in Orkestra, sizing the battery against the site's load profile and tariff structure, stacking the revenue streams, and producing the kind of bankable business case you need to get a project over the line.

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We highly recommend watching the webinar to get a better understanding of how to use Orkestra and create a compelling business case for your solar and battery system.

‍Your C&I Battery and Tariff Questions, Answered

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The Q&A was one of the best parts of the session. Here are the questions that came up most, with answers from the panel.

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Tariffs and Contracts

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"Our customers are on multi-year fixed contracts. Can you put just the battery asset on an agile tariff, rather than the whole site?"

A behind-the-meter battery is tied to the import agreement on that meter point — so applying an agile tariff to the battery means that meter point needs to be on the agile tariff. That said, customers installing BESS should be thinking long term. The benefits will extend well beyond any current fixed contract, so it's worth planning for the right tariff structure even if they can't switch immediately.

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"What happens to time-of-use tariff savings as more batteries get installed across the country?"

Fair question when you're helping customers make long-term investment decisions. More batteries on the grid tend to smooth out price peaks and troughs — which could compress arbitrage margins over time. But more wind and solar also create greater price volatility, pushing the other way. The honest answer is: it's not a simple picture. The best approach is to model a range of future scenarios rather than assuming today's conditions hold forever — which is exactly what Orkestra is designed for.

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"Is the Iran conflict affecting tariff rollout or future availability?"

Shape Shifters Trio is already available nationally and Agile will be available for C&I from June 2026. Current pricing already reflects the geopolitical situation, so there's no additional risk to time-of-use tariff availability.

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EMS and Grid Services

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"Does Octopus provide the EMS as part of Shape Shifters?"

No. Shape Shifters tariffs expose the time-of-use pricing signals — it's up to the customer's EMS to optimise against those signals.

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"Can battery EMS systems access ancillary services like frequency response?"

Yes, and it's a good revenue stream to flag to your customers. Batteries can earn revenue by being available to help balance grid supply and demand, arranged through an aggregator. Some battery EMS options come with aggregation capabilities built in (more common at residential scale), but for C&I it typically requires a separate aggregator relationship. Octopus Energy for Business is exploring C&I aggregation options, and the Orkestra and Midsummer teams can connect you with aggregators if needed.

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"What about P415?"

We still view P415 as a nascent opportunity — it's the cream, not the cake. Worth keeping an eye on, but not something to build the core business case around yet. You can always add this option to a battery once it’s installed. You can read more on P415 here.

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"How does the EMS integrate with existing Building Management Systems (BMS)?"

Inverter and battery manufacturers' EMS units can interact with site BMS — for example, for firefighter E-Stop integration. There are also third-party EMS platforms (such as ComAP) that allow the whole site to be visualised and controlled through a single interface. It's a good but complex question, and the answer will depend on the specific hardware and BMS configuration at each site.

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Octopus-Specific Questions

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"What's the export rate for solar systems on an Octopus import contract?"

The 12p/kWh export tariff applies to systems at or below 150kWp. Larger systems require a specific PPA for their export arrangement.

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"Does Octopus offer export tariffs for battery-only customers?"

Yes — Shape Shifters: Export is open to battery-only customers.

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"Is the Max Power tariff still available?"

Yes, although it's now branded as Electric Match.

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"I don't think Solax works with Octopus Intelligent Flux/Go yet?"

Correct — Solax isn't currently integrated with Kraken. But remember, Shape Shifters works differently. It exposes price signals rather than taking control of assets, so any battery/inverter brand is compatible — not just the Kraken-integrated ones.

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"Can an installer set up a Shape Shifters tariff on behalf of their customer?"

In principle, yes — if you hold a Letter of Authority (LOA) from your customer that permits you to enter into an electricity agreement on their behalf. Request a quote here.

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"Can I get contact details for the Octopus tariff optimisation team?"

The fastest way to get a Shape Shifters: Trio rate is through this form.

For Shape Shifters: Agile (launching June), contact Frances Benson.

General enquiries contact here.

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Orkestra Platform

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"Is the design tool available to installers?"

Absolutely. You can book a call or sign up for a free trial to explore Orkestra Plan.

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"Are there training videos?"

Yes — we have a knowledge hub with documentation and short videos, plus a dedicated customer success team for onboarding and support.

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"Can Orkestra model different tariff structures in its public library?"

Our public library contains hundreds of tariffs to use in your modelling, including the Octopus Shape Shifters Agile tariff for SMEs. For C&I businesses looking at the Agile tariff, each customer will have bespoke rates depending on their agreed capacity and load profile, which makes a standard public tariff trickier — but the Octopus team can help pull rates for specific customers, and we can support the modelling.

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Orkestra also has smart features to help you identify or disqualify tariffs based on your site location and load, and ultimately enables you to optimise your solution to find the best tariff, solar and battery combination to meet your customers needs.

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The Bottom Line

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The UK C&I battery market is moving fast. The tariff products are maturing, the EMS options are getting better, and the modelling tools exist to put it all together into bankable proposals.

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But here's the thing: the installers and developers who win in this market will be the ones who treat tariffs, EMS, and modelling as a single integrated conversation — not three separate workstreams that get stitched together at the end.

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That's the playbook. If you want to see how Orkestra can help you build better battery business cases, book a demo or try it for free.

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