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Joulen

Turn flexibility into revenue.

Joulen Flex gives you a complete route to market for flexible assets, combining optimisation, trading and expert management to unlock new revenue without the operational complexity

We optimise. We trade. You earn.

Flex
Works with the hardware you already run
  • Fox ESS
  • SolaX Power
  • Solis
  • Solplanet
  • Zervio
  • Growatt
  • Sigenergy

Make more from every flexible asset

Flexible assets create opportunities beyond simply storing energy for later use.

Joulen Flex connects eligible flexible assets, batteries and EV chargers alike, to our optimisation and trading capability, helping identify and capture additional value from their flexibility.

We manage the complexity behind the scenes, giving you a simple way to add flexibility to your proposition and create more value from the assets you deploy.

How it works

  1. Connect

    Bring eligible flexible assets into the Joulen platform.

  2. Optimise

    We assess asset availability, operating requirements and market conditions to identify the best opportunities for your portfolio.

  3. Trade

    Our algorithms and trading team manage participation across eligible markets, responding to changing market conditions.

  4. Earn

    The value generated through flexibility and trading creates an additional revenue opportunity from your assets.

The benefits of Flex

  • More value from your assets

    Unlock additional revenue opportunities from flexible assets beyond their primary use.

  • A complete service

    Optimisation, market participation and trading are brought together in one service.

  • No trading infrastructure to build

    Access Joulen's technology, market capability and trading expertise without developing your own operation.

  • Built to grow with you

    Connect more assets as your portfolio develops, with a service designed to scale alongside your business.

Flex, Trade or Grid?

Different assets and business models need different routes to market. Joulen's solutions are designed around where you are in the flexibility value chain.

Flex, Trade or Grid?
FeatureFlexComplete flexibility as a serviceTradeMarket access & tradingGridOptimisation of grid-scale assets
ForInstallers, energy companies & OEMsAggregators, HEMS & EMS providersGrid-scale asset owners & developers
Typical assetsResidential & commercial batteriesAggregated flexible portfoliosLarge-scale batteries & co-located portfolios
OptimisationYesYesYes
Market accessYesYesYes
TradingYesYesYes
Algorithmic biddingYesYesYes
Trade desk executionYesYesYes
Best suited toAdding flexibility to your customer propositionBringing aggregated flexibility to marketOptimising larger-scale assets
Explore FlexExplore TradeExplore Grid

What could your assets earn?

Every portfolio is different. Get an indicative revenue calculation based on your assets and see what your flexibility could be worth.

What kind of site?

5 kW inverter, matched to the system, the smallest that covers the array.

Electricity use2,700 kWh a year

Every figure comes from full-year, half-hourly modelling of the Joulen Flex dataset. Figures are indicative and depend on your tariff, site and market conditions.

Total annual benefit with Joulen Flex

£1,522/ year

Bill today £688. Grid supply costs covered, with £834 a year in profit.

Solar and battery on their own
£961
Joulen Flex adds (optimisation + trading)
£561
Solar alone
£784
Adding the battery
£177
Smart optimisation
£423
Market access (trading)
£138
Battery cycles (optimiser output)
385/yr · 1.1/day
Solar used on site
69%

Includes solar stored in the battery for later use, not only generation used the moment it is produced.

Modelled demand
2,700 kWh / yr
Get the full breakdown, freeA month-by-month projection for your system, reviewed by our team. No obligation.

Indicative only, not a guarantee of revenue. A Joulen expert validates against live market data for your assets.

Assumptions and sources
  • Every position is a full-year, half-hourly model from the Joulen Flex calculator dataset v3 (2,925 models). Home positions are exact; commercial positions between modelled battery-to-solar ratios are interpolated.
  • Home figures include VAT and use Octopus Flux (region E, August 2026 rates). Commercial figures exclude VAT and use an indicative half-hourly commercial tariff.
  • Trading revenue is settled against observed 2025 GB day-ahead prices.
  • Weather is a PVGIS typical year for Birmingham; demand follows Elexon profile shapes scaled to the chosen level.
  • Standing charges are excluded because they do not change with the system. Battery degradation is not modelled and cycling is not limited.

Model flex-dataset-v3-2026-09-03.

FAQs

Flex FAQs

Installers, OEMs and suppliers serving residential and small-commercial customers who want optimised, flexible home energy.

Yes, the optimisation and customer app can run entirely under your brand.

No, Flex works with the batteries and inverters you already install.

Optimise to maximise

Ready to unlock more value from your batteries?

Talk to Joulen about how Flex can help you optimise, trade and maximise the value of your flexible energy assets.

Works with the hardware you already run
  • Fox ESS
  • SolaX Power
  • Solis
  • Solplanet
  • Zervio
  • Growatt
  • Sigenergy