The German automaker's Mini brand is leasing 500 Mini E battery-powered electric cars to consumers now. This is an electric car that must be plugge ... Read more

The Dodge Durango and Chrysler Aspen Two Mode hybrids -- the company's first -- were produced for only about three months in 2008. Fewer than 100 w ... Read more

Two more hybrids join the Ford lineup in 2009: the Ford Fusion and Mercury Milan sedans. That will make a total of five hybrids from Ford. The othe ... Read more

GM is slowly filling out its lineup with a variety of full and mild hybrid powertrains. The simplest and least expensive hybrid system that GM offe ... Read more

In 1999, Honda was first to launch a hybrid in the United States with the first Insight, a strange-looking two-seater that could get about 60 mpg i ... Read more

In 2008, the Korean automaker announced a goal of boosting the fuel economy of its fleet to 35 mpg by 2015. Hyundai plans to do that by rolling out ... Read more

The third generation of the Prius hybrid hits the road this year. The car looks basically the same but gets a few more miles per gallon, about 50 i ... Read more

Two types of batteries currently are used in hybrids and most electric vehicles. Nickel-metal hydride batteries now are dominant and can be found in all of today's hybrids. But nickel-metal batteries are being phased out. There may be some incremental improvements in power, weight and cost in nickel-metal batteries, but no further major breakthroughs are expected. It's an old but reliable technology, and no major r&d money is going into it.

Nickel-metal batteries should start being replaced in late 2010 by lithium ion batteries, the kind used in today's consumer electronics, such as laptop computers. The switch from nickel-metal to lithium ion is being driven by several factors. First, lithium ion batteries are smaller and weigh less. That makes packaging them in a vehicle easier and less expensive for automakers. Also, the dramatically lower weight -- about half the weight of nickel metal -- improves performance and increases driving distance.

In either liquid or gaseous form, hydrogen can be used to power cars driven either by electricity or internal combustion engines. In an internal combustion engine, hydrogen is burned in the cylinders. But this is not viewed as practical for production vehicles because of limited range, packaging issues, cost and complexity.

Most automakers that are working on hydrogen-fueled vehicles are developing an electric motor that gets its electricity from a fuel cell. The fuel cell creates electricity from hydrogen through a chemical reaction that separates the ions and protons as hydrogen passes through a series of platinum-coated plates. The negatively charged electrons create electricity for the vehicle's electric motor. The positively charged ions combine with oxygen and form water vapor that exits from the tailpipe. The fuel cell is an electricity generator only. It does not move the vehicle; the electric motor does.

Hydrogen can be used in a fuel cell vehicle in two forms: liquid and gaseous. Liquid hydrogen carries more energy than gaseous hydrogen but is extremely difficult to store. Gaseous hydrogen must be stored at extremely high pressures onboard a vehicle but can be transported and stored easily in tanks at gasoline stations.

Hydrogen's drawbacks are cost, complexity and lack of a hydrogen fuel production and distribution infrastructure. The cost to install hydrogen refilling equipment at filling stations is huge. Royal Dutch Shell PLC puts it at around $500,000 per station. But hydrogen is seen by some as the holy grail of automotive propulsion because the only thing that comes out of the tailpipe is water vapor.

Limited production of fuel cell vehicles for consumers could begin around 2015 -- if the fuel infrastructure develops. The technical issues keeping fuel cells from production are falling fast. The latest generation of GM's fuel cell, for example, fits in the same space as a regular 2.0-liter four-cylinder engine. Honda, Toyota Motor Corp., Daimler, Hyundai Motor Co. and others are increasing power output, developing technology that enables fuel cells to work at temperature extremes and increasing efficiency.

Still, costs must be reduced dramatically before a fuel cell can be competitive with an internal combustion engine. BMW AG, Ford Motor Co. and Mazda Motor Corp. are testing vehicles that use an internal combustion engine fueled by liquid or gaseous hydrogen.