Residential Solar & Battery Installer
Joulen Flex turned an installer's fleet of home batteries into a recurring revenue line, a fully managed, white-labelled flexibility service at a fixed price per asset.
- [£6M]
- Annual recurring revenue across the fleet
- [12,000+]
- Batteries participating by 2030
- [8 weeks]
- To a live flexibility proposition
Challenge
The installer's business is installation: selling, fitting, and supporting solar and battery systems for homeowners across the UK. That's where their expertise, brand, and customer relationships sit, and rightly so.
What they didn't have was any flexibility or trading capability at all. No forecasting, no optimisation engine, no way to aggregate their installed base into a tradeable portfolio, and no route into the wholesale or flexibility markets. Every battery they installed stopped adding value the moment self-consumption was covered.
Building that capability from scratch, customer consent and onboarding, asset integration, forecasting, dispatch, market access, trading, and settlement, all working as one service, was a multi-year undertaking well outside their core business, and not one they were set up, licensed, or resourced to build.
Approach
Joulen Flex gave the installer the full flexibility stack as a single, white-labelled, fully managed service, sitting behind their own brand and customer relationship rather than replacing it. Joulen took on:
- Portfolio onboarding, a full customer journey, eligibility checks, consent capture, and enrolment for the installer's battery customers
- Asset integration, connecting installed battery systems through approved device and API pathways
- Forecasting & optimisation, forecasting energy needs, generation, and market value, with optimisation decisions refreshed at regular intervals
- Asset dispatch & control, executing optimisation decisions and market commitments through the connected assets
- Self-consumption optimisation, making sure each home's own generation and storage needs stayed protected within the agreed proposition
- Aggregation, market access & trading, pooling the fleet into a single portfolio and trading it into wholesale and flexibility markets through Joulen's market-facing infrastructure
- Settlement & revenue reporting, plus ongoing portfolio operations, monitoring and support
The installer kept what they do best: customer acquisition, hardware supply, installation, and warranty. Commercially, the two businesses agreed a fixed price of £40 per asset, per year rather than the revenue-share model Joulen typically offers, a simple, predictable cost per battery the installer could build straight into their own customer economics.
Results
Joulen Flex turned a previously idle fleet of batteries into an active, ongoing revenue line for the installer, with the flexibility, trading, and market risk staying with Joulen, and the economics of every battery known before it was even installed.
- [£6M annual recurring revenue] generated across the total installed battery fleet, on top of the fixed £40-per-asset-per-year cost to the installer
- [>12,000 batteries] expected to be onboarded and actively participating in flexibility and wholesale markets by 2030
- Live flexibility proposition launched in [8 weeks], without the installer building any optimisation, trading, or settlement capability of their own
- A new, differentiated selling point added to every future installation, at a cost the installer could price with certainty from day one
