Taxes on LPG are low, and at around 39p per litre it offers much cheaper motoring than conventional fuels, although fuel efficiency is slightly lower.
While the fuel burns clean, it is less energy dense than gasoline, so if it is burned in an engine designed to run on conventional fuel, performance and efficiency are degraded.
This is because that lignocellulosic biomass generally cannot be directly used as a fuel for electricity generation in a conventional fuel cell with high efficiency.
Environmentalists carp that industry is simply trying to preserve the status quo and avoid more immediate steps to improve the fuel efficiency of conventional automobiles.
Advances in the fuel efficiency of conventional gasoline engine cars, and relatively stable fuel prices make Prius's price premium harder to justify.
The industry is investing heavily in improving the fuel efficiency of conventional cars as well as in designing hybrids and vehicles powered by alternative fuels like electricity and hydrogen, Mr. Hodac said.
The rise in fuel efficiency in conventional vehicles, along with the growing popularity of hybrids, could also mean all-electric cars will struggle to gain much market share, according to a report released last year by the Boston Consulting Group.
Minnesota (US) Axsen et al. [10] HEV, conventional Capital cost, subsidy, performance, fuel efficiency and fuel price.
The study also include hybrid electric vehicles in the comparison, and analyzed several scenarios to determine how the comparative net savings will change over the next 10 to 20 years, assuming that battery costs will decrease while gasoline prices increase, and also assuming higher fuel efficiency of conventional cars, among other scenarios.
The Toyota Prius, which runs on gasoline and electricity, "gets twice the fuel efficiency of a conventional car of the same class and has much cleaner emissions," said Paul Nolasco, a Toyota spokesman.
