See excerpts from LA Times:
How? By mobilizing the government's vast purchasing power to kick-start a green energy revolution. Federal spending is responsible for roughly 25% of the gross national product, giving Washington enormous power to influence marketplace behavior even if annual spending levels are trimmed.
The federal government is the world's largest consumer of energy and vehicles. If the Pentagon, the Postal Service and other agencies shifted their buying wherever possible from dirty technologies to clean ones, it would give manufacturers such as Smith Electric Vehicles, headquartered in Blunt's state, a huge influx of orders. These orders would yield economies of scale that would enable green manufacturers to substantially reduce prices.