Hydrogen fuel cells could be the energy panacea the transportation sector needs, if only the infrastructure requirements and enormous cost are dealt with. Hydrogen is the most abundant element in the universe. It powers the sun, which in turn provides the energy needed to sustain life on earth. Harnessing that energy in a way that's efficient and clean could revolutionize personal transportation.
History
In 1839, Sir William Grove built a rudimentary "gas battery" that included one bottle filled with hydrogen gas and one filled with oxygen connected via a wire and platinum electrodes. It would be 50 years before Ludwig Mond and Charles Langer would take Grove's preliminary research and develop it into a commercially viable device they called a "fuel cell."
The first fuel cell-powered vehicle arrived in 1959. Karl Ihrig, a farm equipment manufacturer, developed the stack, a series of cells linked together. His enhanced design produced 15 kW of power, enough to power his 20-horsepower tractor.
The automotive industry rediscovered fuel cells in the 1980s. Most major car manufacturers have built at least a prototype of a fuel cell-powered passenger car.
The Basics
Fuel cells proposed for use in passenger cars are of the Proton Exchange Membrane variety, or PEMFC. There are no moving parts inside the fuel cell. Instead, a fuel---in this case, hydrogen---enters the cell and meets a catalyst membrane that ionizes the hydrogen atoms, or splits them into electrons and protons. The protons pass through the membrane and combine with oxygen from the air to form water, the systems only by-product besides waste heat. The electrons cannot pass through the membrane, so they travel around it from the anode in the electrical circuit to the cathode, creating an electrical current.
Powering the Vehicle
There are two power sources in a fuel cell vehicle. The PEMFC is the primary driver of the wheels. All of the electricity generated by the cell powers an electric motor, which turns the wheels. A battery pack provides a secondary source of electricity, which powers the car's peripherals and adds supplemental power to the electric motor when needed.
Hydrogen is stored on board at pressures of up to 10,000 pounds per square inch. A power control unit modulates the flow of electricity between the fuel cell and the motor. It does the job of a carburetor in an internal combustion engine, though in this case, the fuel is electricity instead of gasoline and air. When you step on the accelerator in a fuel cell car, you get a commensurate reaction that is as similar to a gas-powered car as engineers can manage.
Implementation
The two biggest hurdles fuel cell cars must overcome are high cost and a lack of infrastructure. Platinum is the material of choice for the catalyst membrane due to its efficiency, but it's is prohibitively expensive to manufacture at scale. The U.S. Department of Energy estimates that manufacturers will need to find a way to use four times less platinum in the stack before fuel cell cars can be competitive with their internal combustion engine-driven counterparts.
There is also precious little infrastructure to advance a hydrogen economy. Hydrogen must be distributed either at very low temperatures or extremely high pressures in order to reduce it to a liquid state. This would require a vast network of properly outfitted trucks and pipelines, not to mention the fuel stations to take delivery of the liquid hydrogen.
Criticism
It is enormously energy-intensive to produce the fuel for hydrogen cars. Until power generation comes from such clean sources as wind, solar or geothermal, the environmental benefit gained from a zero-emissions vehicle is more than offset by the pollution generated creating the fuel.
Member Comments