摘要：Climate change and energy security require a reduction in travel demand, a modal shift,
and technological innovation in the transport sector. Through a series of press
releases and demonstrations, a car using energy stored in compressed air produced
by a compressor has been suggested as an environmentally friendly vehicle of
the future. We analyze the thermodynamic efficiency of a compressed-air car
powered by a pneumatic engine and consider the merits of compressed air versus
chemical storage of potential energy. Even under highly optimistic assumptions the
compressed-air car is significantly less efficient than a battery electric vehicle and produces
more greenhouse gas emissions than a conventional gas-powered car with a coal
intensive power mix. However, a pneumatic–combustion hybrid is technologically
feasible, inexpensive and could eventually compete with hybrid electric vehicles.
