The switch to Sunoco Green E15, the official fuel of NASCAR and a renewable, low-carbon power source, reduced greenhouse gas emissions by 20% compared with unleaded gas.

FORBES: NASCAR Green Is Really Purple

Microturbines provide high electrical efficiency compared with traditional gas turbines in the same size class.

FORBES: America's Other Energy Revolution And Why It Matters

But there are at least two major obstacles hindering wider adoption of plug-in electric vehicles: the premium that drivers will have to pay for an electric car compared with a gas-powered vehicle and the limited number of electric car charging stations nationwide.

FORBES: More Electric Cars Are Making Their Way Across the Country