The Smart Export Guarantee (SEG), introduced by the UK Government in January 2020 to replace the legacy Feed-in Tariff (FiT), mandates that licensed electricity suppliers with over 150,000 domestic customers must offer an export tariff to small-scale low-carbon generators. For UK homeowners investing in solar PV systems, navigating these tariffs is essential for calculating realistic payback horizons.
How the Smart Export Guarantee Operates
Unlike the old Feed-in Tariff, which paid fixed rates regardless of whether electricity was exported or consumed on-site, the SEG strictly compensates homeowners for energy metered and exported to the national grid.
To qualify for SEG payments, domestic installations must satisfy two fundamental requirements:
- MCS Certification: The solar array and any paired storage hardware must be installed and signed off under the Microgeneration Certification Scheme (MCS) or an equivalent accredited standard.
- Half-Hourly Export Metering: Properties must have an operational second-generation smart meter (SMETS2) capable of recording half-hourly export readings and communicating them automatically to your energy supplier.
Fixed vs. Dynamic Export Tariffs
UK energy suppliers determine their own export rates, resulting in substantial competition across the domestic market:
- Fixed Outgoing Tariffs: Provide a stable, guaranteed rate per kilowatt-hour (kWh) exported across all 24 hours of the day (typically between 8p/kWh and 15p/kWh depending on whether the customer also purchases import electricity from the same provider).
- Dynamic / Variable Tariffs: Peg export earnings to wholesale electricity market fluctuations or offer enhanced overnight charging combined with elevated daytime peak export rates (such as intelligent EV and home battery tariffs).
The Role of Battery Storage (LiFePO4)
Adding a lithium iron phosphate (LiFePO4) battery system dramatically transforms solar economics. Without battery storage, typical UK working households consume only 30% to 40% of their rooftop solar generation, exporting the remainder during peak midday sunshine when household demand is lowest.
A properly sized home storage battery (typically 5 kWh to 10 kWh):
- Captures daytime surplus energy for evening and morning domestic use.
- Increases self-consumption rates from ~35% up to 75%–85%.
- Enables time-of-use tariff arbitrage, allowing homeowners to charge batteries from the grid at cheap off-peak rates during winter months when solar generation is low.
Grid Connection Compliance: G98 vs. G99
Domestic battery systems integrated with solar inverters must comply with UK Distribution Network Operator (DNO) regulations. If total inverter continuous export capability is restricted to 16 Amps per phase (3.68 kW on single phase), the installer submits a standard G98 notification after commissioning. Higher-capacity dual inverter or hybrid setups require prior G99 engineering clearance from the local network operator before installation.
Frequently Asked Questions About Smart Export Guarantee (SEG)
Can you export electricity without a smart meter?
No, under Ofgem regulations, domestic generators can use export-only tariffs…
A smart meter capable of providing half-hourly export readings is a mandatory regulatory requirement for participating in the Smart Export Guarantee scheme across England, Scotland, and Wales.
Do you have to buy energy from the same supplier you export to?
No, UK regulations permit export-only tariffs. Homeowners can purchase import power from one licensed supplier while selling exported surplus solar generation to an entirely different SEG licensee offering higher rates.
How can you calculate potential export earnings?
Your annual export earnings depend directly on solar array sizing, battery capacity, and peak household consumption. You can evaluate your setup using our interactive UK Solar & Battery Savings Calculator on the homepage.