According to Ms Allen, the pop star said her experiences at an environmentally friendly studio showed her the benefits of green electricity.
She explained: "Having worked at The Premises solar powered recording studio I have experienced how clean and green renewable energy is.
"I fully support giving people a renewable energy reward for the power they generate. It's good to be green."
The singer's support for the green energy campaign has come after the government urged business electricity customers to apply for grants to install combined heat and power systems.
Climate change minister Phil Woolas announced details of the £4 million fund at the start of this month.
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