Ovo will pay £1.2m in redress after SSE Energy Services failed to meet its smart meter installation target for 2019.
Ovo acquired the SSE’s domestic retail customers earlier this year for £500m.
SSE paid a smaller penalty, £700,000 the year before after missing 2018 targets.
Suppliers are obliged to take ‘all reasonable steps’ to at least offer customers a smart meter.
The original 2020 rollout deadline has been extended to 2025. From next year, suppliers will be set more stringent annual targets, reset yearly.