US Energy Secretary Steven Chu has urged Congress to consider nuclear power and cleaner-burning coal in a mandate for utilities to use more clean energy to generate electricity.

Additional energy sources including renewable energy should be looked at as part of a clean energy standard, according to Chu.

Chu calls for mandating utilities to generate 25% of their electricity from clean energy sources by 2025 and 50% by 2050, reports Reuters.

According to the legislation by the Senate Energy and Natural Resources Committee, utilities would need to generate 15% of their power from renewable energy sources like wind, solar and geothermal by 2021.