Co-op is changing the way it lights its stores in an effort to soften the blow on rising energy bills.
The supermarket is trailing reduced lighting in around 500 of its 2,500 stores, with hopes to save £4,000-a-year per site.
This could amount to a huge energy bill saving of £10million per year across all stores.
And Co-op is not the only retailer making big savings by cutting back on the use of lighting in stores.
The news comes as competing supermarkets, including Sainsbury’s and Morrisons have made similar moves.
Sainsbury's goal to become net zero in its operations by 2035 means it has been lowering its lighting on brighter days, and when stores are less busy.
Last year, the supermarket finished rolling out LED lighting across stores to cut back on its energy consumption.
Sainsbury’s has also been automatically monitoring and controlling its lighting in stores to make further savings, as the automated system ensures that stores are only lit when required.
Rival chain Morrisons follows a specific routine, dimming its store lighting for the first and last hour of trade, with an additional "quiet hour" on Saturdays.
The supermarket began reducing its lighting since the coronavirus pandemic and has seen the benefits of reduced energy bills.
Co-op said it was trialing the initiative to reduce its environmental impact and help cut costs on energy in the long run.
A spokesman said the company has been reviewing how it can be a "more energy efficient business, without compromising safety and still achieving a positive store environment and shopping experience."
The National Grid has announced its plans to launch a new scheme from 1 November which aims to incentivise businesses and households to cut down on their electricity use.
This will help reduce further pressure on the energy supply this winter.
As part of the scheme, larger businesses will be paid for reducing demand.
For example, if they limit their energy at key times, or switch to batteries or generators instead.
Last week, industry regulator Ofgem said that the UK faces "a significant risk" of gas shortages this winter.
This could have an effect on electricity supplies, and prompt other businesses to review their energy usage.
The cost of energy was already on the rise as the demand for energy rose as Covid restrictions came to an end.
But now, conflict in Ukraine has reduced the availability of Russian gas, increasing costs even further.
