What are some of the sources of hydrogen?
Hydrogen is a light gas that easily combines to form chemical compounds with elements like oxygen or carbon. Therefore, hydrogen can be extracted from various compounds, including, but not limited to water, natural gas, propane, methanol, petroleum, coal, or various biomass feedstocks.
If water becomes the main source of hydrogen, will there be enough?
The Delft Institute for Sustainable Energy  calculates:
- Global energy demand: 4x10^20 J/year
- H2 from water: 1 GJ per 90 liters H2O
- Water needed: 3.6x10^13 liters
- Oceans: 1.45x10^21 liters
- Annual rain fall: 3.63x10^17 liters
If hydrogen is used with fuel cell technology, the by-products of the process are water and heat. This means that the water used to create hydrogen will be reconstituted into an H2O molucule through the production of electricity in a fuel cell.
How much energy do we need to create hydrogen?
Creating useful energy from raw materials always uses energy. The process of extracting oil, refining the crude oil into motor gasoline, and transporting the gasoline to the gas pump results in that form of energy losing the equivalent of 20% of its energy value. To produce hydrogen, using currently available technologies, requires more energy than producing gasoline. A full consideration of the efficiency of fuels in their end-uses is more favorable for hydrogen. Since hydrogen used in a fuel cell is more efficient than conventional energy, the comparison becomes much more equal.
What is a fuel cell?
A fuel cell provides direct current (DC) electricity in a manner similar to a battery. Unlike a conventional battery with a finite storage of energy, a fuel cell can produce electricity as long as there is a flow of hydrogen. Although there are several technologies (see H2 and FC Properties), all fuel cells contain an anode, cathode, and electrolyte. The hydrogen fuel is broken into electrons and protons by virture of a catalyst, and combines with oxygen supplied to the fuel cell to create electricity, water, and heat.
Source: Fuel Cells 2000
How does a fuel cell compare with conventional energy generation technologies?
Electric power is by and large generated by using a steam cycle turbine. Fuel is burned to produce heat, which then produces steam. The steam turns a turbine that powers a generator to produce an electric current. A fuel cell, on the other hand, directly converts the fuel's chemical energy to electricity.
What are some advantages of fuel cells?
Fuel cells are quiet and modular, which means they can be used as distributed generation resources. The emissions or other environmental impact of the fuel cell itself are 100% clean, however, the life cycle of the hydrogen fuel cell must consider the source of the hydrogen. Theoretically fuel cells are also highly durable when using pure hydrogen gas. The only byproducts of the generating process are heat (which cogeneration systems utilize for water and space heating) and water. Fuel cells have been used by NASA on space shuttles for several decades to provide power and drinking water on board.
In addition, a fuel cell operates at an efficiency of 40-50%, significantly higher than conventional power generators. A steam power plant is typically 35% efficient, while the efficiency of an internal combustion engine in most vehicles is only about 15%.
Are fuel cells being used in applications today?
Most fuel cell applications are in demonstration or early commercialization phases. Currently the most promising applications are using fuel cells for "remote power" or distributed generation, such as off-grid homes, weather monitor stations, telecommunication infrastructure, or onsite grid-integrated stationary power or CHP. Fuel cells are also being developed for use as portable power for electronic devices, such as cell phones or laptop computers. Ultimately, research and development teams want to achieve market-viable vehicular power for automobiles, trucks, boats, etc. There is a plethora of fuel cell vehicle prototypes developed in the industry. Issues of per-horsepower cost based on fuel storage issues that impact weight and range of the vehicles hinder the cost competitiveness of these vehicles compared to internal combustion engines.
If fuel cells are so great, why aren't we using them?
Fuel cells are actually being used more widely than many people think. In addition to a few high-profile applications such as the space shuttles, the organization Fuel Cells 2000 lists over 600 past and present fuel cell installations worldwide on their website. However, fuel cells are still meeting only a tiny fraction of our energy generation needs.
There are two main reasons fuel cells have not yet caught on more broadly. One, development work still needs to be done. Two, the price is currently too high. There is nothing inherently expensive about a fuel cell but as with most technologies, prices will not be competitive until many units are sold. By demonstrating the practicality and environmental benefits of fuel cell power, the Schatz Energy Research Center's projects are an important step in advancing the worldwide effort to make fuel cells widely available.
1 Frequently Asked Questions have been developed from Fuel Cells 2000 and Schatz Energy Research Center Humboldt State University, click on the sources to go to these webpages.
2 The Delft Institute for Sustainable Energy's findings were presented on the Fuel Cells 2000 website. To visit the Institute's website, click here.