Tesco Fanz. Energy Saving Report Application
An offline-first mobile app that turned a 30-minute spreadsheet routine into a 5-minute task for Tesco store teams.
Overview
Tesco (UK) needed a better way for store managers and facilities teams to monitor, log and report energy consumption across its retail locations.
Energy data feeds directly into sustainability reporting, so the information had to be accurate, complete and easy to collect during a busy working day — not something squeezed in at a desk at the end of a shift.
- Project typeMobile Application
- ClientTesco (UK)
- TechnologiesFlutter, Firebase
- Timeline6 Months
- Year2024
The challenge
Energy reporting relied on manual spreadsheets. Each report took around 30 minutes to complete, and regional managers had no live view of what was happening across their stores.
The bigger obstacle was connectivity. Reports are filed from inside the stores themselves, and mobile signal varies from location to location. A tool that only worked online would lose data exactly where it was being collected.
Goals
- Replace manual spreadsheets with a fast mobile workflow built for daily field use
- Capture readings reliably, even with weak or no signal
- Restrict reporting to authorised personnel
- Give regional managers real-time visibility across every location
Our approach
We started with the hardest constraint: unreliable connectivity across hundreds of store locations. Rather than treating offline use as an edge case, we designed the app local-first, so every entry is saved on the device the moment it is made.
Firebase handles background sync. Whenever a connection is available, saved entries are sent automatically, without the user having to retry or re-enter anything. The result is a data-entry flow that behaves the same in a back room with no signal as it does on the shop floor.
Because the reports support Tesco's sustainability targets, data integrity mattered as much as speed. We layered role-based access controls on top, so only authorised personnel can submit and manage reports.
Flutter let us deliver one codebase with a consistent, fast interface for the teams using it every day.
Key decisions
- Local-first by default. Saving every entry on the device first means a dropped signal delays a sync, never loses a reading.
- Sync in the background. Staff never have to remember to upload or retry; Firebase sends entries as soon as it can.
- Access matched to responsibility. Role-based permissions keep sustainability data trustworthy by limiting who can report.
What we built
- Mobile energy loggingA streamlined interface for recording energy consumption during the working day, replacing manual spreadsheets.
- Offline-first data entryEntries are stored locally first, so nothing is lost in low-signal areas.
- Automatic background syncFirebase syncs saved entries as soon as a connection returns.
- Role-based accessReporting is restricted to authorised personnel.
- Real-time dashboardsRegional managers see consumption and reporting status across all locations as it happens.
The results
Tesco Fanz was deployed across Tesco locations. Store managers moved from a 30-minute manual process to a 5-minute mobile workflow, cutting report submission time by over 60%.
Real-time dashboards gave regional managers visibility across every location, directly supporting Tesco's sustainability reporting targets.
Tech & delivery
Tesco Fanz was designed and built by the Prognesoft team over 6 months, following our process: discovery, architecture and design, development and testing, then launch and support.
Have a similar project?
If your teams collect data on the move — in stores, sites or warehouses — the same principles apply: offline-first capture, automatic sync and clear permissions. It is how a 30-minute admin task becomes a 5-minute habit.
