Short answer

Smart tariffs can materially alter battery economics, but the result depends on half-hourly prices, grid-charging permissions, export terms and automated controls. Treat generic arbitrage promises as unverified until modelled against the actual tariff.

Why the simple model stays conservative

The public X-ray uses the import and export rates you enter and does not manufacture future arbitrage income. That makes quotes comparable even when suppliers change products or promotional rates.

Information needed for a tariff model

A proper time-of-use simulation needs interval demand, solar generation, charge and discharge limits, reserve settings and every tariff period.

  • Half-hourly import prices
  • Half-hourly export payments
  • Battery charge and discharge power
  • Grid-charging eligibility
  • Standing charges and tariff conditions

Questions for the installer

Ask whether projected savings require a particular supplier, tariff or virtual power plant, and what happens if you switch. A hardware purchase should not be justified by a tariff that may disappear.

Primary sourceOfgem — Smart Export Guarantee annual reportsRule or guidance checked 24 August 2026.
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