This article describes Hybrid / Fuel Cell technology in automobiles. For a broader discussion of fuel saving technology and alternative energy in automobiles see Hybrid and Alternative Energy Technology. For Renewable Energy beyond the automobile industry, see Renewable Energy.
Hybrid cars are powered by a combined set of chemical (fuel) and electrical (battery) energy. The fuel is converted to mechanical energy in a combustion engine or to electrical energy in a fuel cell stack. The battery in the hybrid vehicle can be used to store energy during deceleration or to be loaded from the grid. The electrical drive is used as a generator during deceleration of the vehicle.
The combustion engine is powering a generator and the electrical energy is buffered in a battery. The electrical drivetrain is powered by the battery. The concept allows to run the combustion engine under ideal conditions to achieve maximum efficiency of the combustion cycle. A front driven series hybrid with electrical transaxle does not require a gearbox. A typical example of this hybrid type is GM's Chevrolet Volt.
The vehicle is driven by a combustion engine with the assistance of an electric drive between the engine and the transmission. A battery is able to store energy during deceleration and to spend energy to the electric drive during acceleration. The Honda Insight is using this concept.
Full parallel hybrids can be either powered by the combustion engine, the electrical drive or both. This is the most complex concept of a hybrid vehicle and requires a full size electrical drive and a powerful battery system. The Ford Fusion Hybrid and the Toyota Prius are typical examples of this concept.
Fuel cell hybrids are equipped with a fuel cell stack for the conversion of Hydrogen or Methanol to electrical energy. The electrical energy is buffered by the battery and converted by the electrical drive into mechanical energy. Fuel cell hybrids require advanced storage technology for the hydrogen and conversion technology for the electrical energy (e.g. converters). Special technology is required for supporting aggregates (e.g. heating, power steering). Fuell cell hybrids do not require gear shifting due to the torque specifics of the electrical drive. A typical example for a fuel cell car is the Honda FCX Clarity. Fuel cell vehicles are still under development and not ready for mass production and sale. However, fuel cell producers are introducing the concept already in niche markets (e.g. to power forklift trucks).
The plugin property is independent from the hybrid type and requires advanced battery storage (e.g. Lithium based) and electronics to manage the grid connection. NiMH batteries do not have sufficient capacity for plugin usage.
The US government has been funding generous tax credits for buyers of select hybrid vehicles (dollar amount ranges from US$400 to 3,400, depending on the model) to encourage both hybrid adoption and production. However, the tax credits don't last forever, and they won't be distributed evenly across the industry, either. After an automaker sells 60,000 tax-credit-eligible hybrid cars, the amount of tax credit per buyer gradually drops to 0% of the original amount over a period of five years. This may help automakers who were slow on the hybrid uptake to compete with those who jumped the gun on hybrid technology, but the artificial equalizing effect may make investing in hybrid automakers more difficult.
In July 2008, the National Research Council published a study stating that, though fuel cell vehicles might make up 35 million of America's cars by 2030, the industry would need $200 billion in investment capital for infrastructure, technology development, and manufacturing. Platinum would make up a large part of these costs, as the cost of the metal makes up 57% of a fuel cell's costs.
The following concepts are also limiting the greenhouse gas emissions and reducing resource usage of transportation: