Initiatives include education programmes for both adults and children, as well as a scheme to reduce fuel poverty in Wales.
The supplier has also donated funds and equipment to several charities and organisations.
Anita Longley, head of corporate responsibility for npower, said the supplier "is proud to receive the prestigious CommunityMark.
"This award recognises the achievements, hard work and dedication of the people that work across our 60 sites."
Recent research by YouGov for npower found that 93 per cent of employees in the UK feel it is important to be energy efficient in the summer.
It was also found that over 40 per cent of workers were planning to take energy saving actions in the next few months.
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