The Carbon Trust made the award after assessing GSK’s carbon footprint over the last three years, covering operations at 200 sites in 65 countries.
Over the assessment period, GSK reduced its carbon footprint by over 84,000 tonnes of CO2 equivalent and saved £3.8 million in energy costs.
The company installed wind turbines at its Barnard Castle facility in the UK and a rooftop solar array at its regional distribution centre in York, Pennsylvania.
GSK has also installed energy efficient lighting at five sites and implemented a canal water cooling system for its IT data centres at its headquarters.
The measures are the first stage of the company’s plans to reduce its carbon footprint by 10% by 2015 and 25% by 2020, before becoming carbon neutral by 2050.
“Not only did the scale of the project set a new benchmark for carbon reduction amongst businesses, but the extent of our cuts proved that it is possible to achieve a meaningful reduction in emissions,” said Richard Pamenter, head of sustainability at GSK.