A renewable energy source defines the energy that is sustainable - something that cannot run out or is endless, like the sun. When you listen to the term alternative energy it's normally relating to renewable energy sources too. It implies sources of energy that are substitutes to the most generally used non-sustainable sources - like coal.
The most prevalent renewable energy sources currently are:
A heterogeneous catalyst works a binary role in the transesterification reaction owing to the advantages of parting and reusability. Lately, heterogeneous catalysts obtained from renewable sources have gotten more attention. The renewable resources defined cover shells, bones, ashes from plant/tree, natural sources, large-scale industrial wastes, etc. considerably, catalysts provided from these materials could make the biodiesel product more sustainable, environmentally friendly, and cost-effective.