At present there is a universal anxiety about the economic decline and a greener globe which is correlated to an improved and efficient system to generate and transmit electric power. With the initiation of the plug-in electric vehicles and renewable energy generators, a smarter, more efficient and customer-friendly power grid is indispensable that is “Smart Grid”. This paper depicts the importance, characteristics and evolution of smart grid. The allied new concerns, environmental impacts and benefits of smart grid are illustrated here. In brief platform for smart grid R&D is also portrayed. It is highlighted that though the smart grid implementation is promising, it faces mammoth challenges. The voyage to smart grid is an extensive when diverse technologies will coexist. Finally the future key challenges are enlisted as a guideline for the successful implementation of Smart Grid for the sustainable future.