Hydrogen Or Fuel Cell - Which Comes First?
By Resource. via ProQuest Information and Learning Company
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The conventional wisdom is that the cost of fuel cells will drop dramatically when significant numbers are sold, but this will not happen until hydrogen-refueling stations are as common as gasoline stations. The classic chicken-and-egg question appears: "Which comes first?" The American farmer will lead us in breaking this quandary by being early users of fuel cells and even "growing" their own hydrogen.
How?
Farmers are constantly looking for ways to improve their productivity, and energy costs are a farmer's biggest expenditure after land expenses and inputs such as feed, seed, and fertilizers. Using hydrogen and fuel cells will significantly reduce the use of diesel, natural gas, propane, and imported electricity on the farm. In fact, many American farmers could "grow" their own hydrogen and use it now in their internal combustion engines (ICE) and in fuel cell-powered equipment. Thus, farmers could be the vanguard users of both hydrogen fuels and fuel cells.
Today, hydrogen is being used in conventional ICEs that have been modified to use natural gas. This blend of hydrogen and methane gas is called hythane. Tests are now under way at the University of California-Davis using a John Deere compressed natural gas engine with blends of up to 40 percent hydrogen, without significant engine modifications. BMW, Ford, and others have also been demonstrating specially designed engines which run solely on hydrogen.
For other ways to reduce fuel costs, farmers could go beyond hydrogen powered ICEs, to hydrogen fuel cells, which can power most kinds of farm machinery. The first application of fuel cells will most likely be in a hybrid configuration with a small diesel engine providing tractive power, and a fuel cell auxiliary power unit (APU) driving the implement and all auxiliary loads. As fuel cells become more advanced they will replace the diesel engine, although total replacement is not likely for decades.
The most common mobile fuel cells now being used are called proton exchange membrane, or PEM fuel cells. A PEM fuel cell can be thought of as a powered battery. To operate, one feeds hydrogen in and gets only electricity, water, and heat out. The principle is very simple. The heart of a PEM is a thin membrane coated with a platinum catalyst. As hydrogen flows through the membrane, the platinum catalyst strips an electron from the hydrogen atom. The hydrogen proton on the other side of the membrane then combines with oxygen to form water. This reaction generates electricity, water, and modest amounts of low-grade heat.
Fuel cells can be used in both mobile and stationary applications. Stationary fuel cells can generate electricity to power buildings and other structures. Like mobile fuel cells, they are emission-free enabling clean and almost silent operation. These characteristics make them perfect for indoor and public-space use. These benefits are also important on farms, both for the land and for the people and animals that live there. For all these reasons, we can envision significant functional and economical improvements when fuel cells and hydrogen fuels are available.
As this new technology emerges, some believe that infrastructure issues and the source of hydrogen are potential problems. Hydrogen availability is a concern as people analyze the systems necessary to support the use of fuel cells. In the area of mobile fuel cells, it is likely that fleet vehicles - where one hydrogen "pump" can serve the entire fleet - will enable fuel cells to hit the roads and byways more quickly.
Where will this hydrogen for the farmer's "pump" come from? Though it is the most common element in the universe, hydrogen does not occur freely in nature. It is obtained by extracting it from a molecule. Most hydrogen today is made in chemical plants and is derived from oil or natural gas by thermal reformation. Thermal reformation can also be used to derive hydrogen from ethanol, methanol, and many other materials. Though production of hydrogen from such sources is much cleaner than burning liquid fuels in internal combustion engines, it still does not eliminate the generation of the so-called "greenhouse gases" such as carbon dioxide.
The best choice for the environment is to obtain hydrogen by the electrolysis of water-separating the hydrogen from oxygen with electricity. Today, this is not the best economic choice, nor can it always be done with clean sources of electricity. However, on the farm today, hydrogen could be generated in significant quantities using electrolyzers powered by wind turbines or solar photovoltaic cells. With advancing technology, such systems are now economic in some areas.
John Deere ePower Technologies is anticipating this revolution by developing technology demonstrator vehicles to understand how these new power sources can be integrated into future Deere products. The first of these is the fuel cell Commercial Work Vehicle technology demonstrator. It is derived from the John Deere ProGator(TM) utility vehicle and is a series hybrid power configuration using a 20 kilowatts (27 horsepower) hydrogenics fuel cell power module together with nickel metal hydride batteries to power a Solectria two electric motor drive train. It has a 5000-PSI (350 bar) Dynetek hydrogen storage tank that can provide enough fuel for about 4 to 6 hours of normal operation. It can be refueled in about 5 minutes from a variety of sources using industry standard hydrogen refueling fittings. Because it is electrically powered and electronically controlled, it is not only four-wheel drive, but also is fourwheel steer. With the flip of a switch, the entire energy capacity can be diverted to a power strip on the back of the vehicle.
An electric system offers flexibility in design that is not possible with mechanical and hydraulic systems. It can run on batteries alone, and when short bursts of extra power are needed, it can draw from both the fuel cell and the batteries. It can also capture the energy of braking via its regenerative power management system. Though this vehicle may not become a commercial product, it is providing Deere engineers and customers with a view as to what is possible using these new combinations of technology.
This vehicle is now undergoing testing and will be demonstrated with customers, partners, and public policy makers in a number of locations in the United States, Canada, and western Europe throughout 2003.
It is possible that versions of this technology could end up in commercial vehicles offered by John Deere before the end of the decade. Since most John Deere vehicles are fleet based, and therefore can avoid some of the hydrogen infrastructure issues that other vehicles face, there are likely to be significant numbers of John Deere fuel cell hybrids in use before we see quantities of fuel cell cars and trucks on our streets and highways.
The hydrogen fuel cell technology is proving to be a viable energy alternative for an efficient, environmentally friendly, and sustainable power source. As this new revolution continues to grow, it will benefit farmers, the environment, and our communities. Energy costs such as diesel, natural gas, propane, and grid electricity may be a thing of the past as farmers become growers and users of hydrogen.
Hydrogen or fuel cells - which comes first? As the farming revolution continues - in ways that benefit farmers, our environment, and our communities - America will reduce its dependence on foreign oil and limit the production of greenhouse gases.
