Solar and batteries
Import, export and generation meters (and MPANs) explained
The difference between import, export and generation readings for solar homes, why export needs its own MPAN, and what each one is used for.
Edited by Rob Gibbs. Published: . Guidance reviewed: .
Short answer
Import is what you buy from the grid, export is what you send back, and generation is what your panels produce. Import and export are recorded by your smart meter. Export needs its own registration, an export MPAN, before you can be paid. Generation is measured by a separate generation meter or inverter and is never billed.
Three different numbers
Each one has a different job:
- Import: billed at your import tariff’s unit rate, with a standing charge.
- Export: paid at your export tariff’s rate, with no standing charge.
- Generation: what the panels made. Some of it you use, some you export.
Why export needs its own MPAN
An MPAN is a supply number. Your home already has one for import. Export is registered separately, with its own export MPAN, and payments only start once that is in place and your smart meter is recording exports half-hourly.
Where to find your numbers
Your import MPAN is the 13-digit number on your bill and in your Octopus account. Your export MPAN appears once export is set up. Generation figures come from your inverter or generation meter, not from Octopus.
Questions people ask
Do I get paid for everything my panels generate?
No. You are paid for what you export. What you use yourself saves you the import price instead.
What is an export MPAN?
The supply number used to register and pay for electricity you send to the grid. It is separate from your import MPAN.
Tariffs in this guide
Related guides
- How big should your solar and battery system be?How to size solar panels and a home battery for your usage, the battery sizes Octopus installs, and how sizing affects which tariff pays best.
- Solar panels with Octopus Energy: getting the most from themHow to set up solar panels with Octopus: getting paid for export, choosing an import tariff, and when a battery or EV changes the answer.
- A home battery without solar on Octopus: does it pay?How a home battery without solar panels can save money on Octopus by charging cheaply overnight, and what to check first.
- Octopus Charge Pack: the home battery add-on explainedWhat Octopus Charge Pack does with your home battery, which tariffs and batteries it works with, what you earn and who should skip it.
- Your fixed tariff is ending: what to do and whenThe 49-day exit-fee window, the 45-day point when Octopus shows your options, and what happens if you do nothing when a fix ends.
- What is Octopus Energy? Tariffs and how it differsA plain-English introduction to Octopus Energy: who it is, the kinds of tariff it offers, and how to find the right one for your home and region.
Primary sources
- Export tariffs terms and conditions — Octopus Energy; checked 2026-08-27. Export contract, metering, MPAN, half-hourly data and generation eligibility requirements.
- Smart Export Guarantee guidance for generators — Ofgem; checked 2026-08-27. SEG scope, eligible generation technologies, application and payment principles.
- What is an MPAN? — Octopus Energy; checked 2026-10-30. Where to find the 13-digit MPAN on a bill or in the Octopus account.