Endorsed by the Sierra Club, Kay Hagan favors extending and expanding tax credits for businesses and individual homeowners who make energy-efficiency improvements to their properties, encouraging the market for green products. Hagan supports tax credits to businesses and homeowners for purchasing plug-in hybrid vehicles. She also believes that the US should be a leader in addressing climate change and reducing greenhouse gas emissions. Hagan vehemently supports the call for cap and trade policy and subsequent investments into renewable energy production to reduce greenhouse emissions 60-80% by 2050.

During her time in the North Carolina State Senate, Hagan supported the state renewable electricity standard.