How Do We Obtain Hydrogen?

There are a number of resources than can be used to produce hydrogen. These include but are not limited to using fossil fuels, natural gas, biomass, nuclear, and other alternative energy sources such as hydroelectric, solar, wind, and geothermal energy production sources. One of the reasons behind the significant amount of research into hydrogen as an alternative energy source is the abundance of the resource. When hydrogen is produced, it can be at a centralized plan that is hundreds of miles from where the hydrogen will be used or in small distributed locations such as a refueling station or local power site location.

How Do We Produce Hydrogen?

There area several methods and technologies used to produce hydrogen to include natural gas reforming, renewable elctrolysis, gasification, renewable liquid forming, nuclear electrolysis, and photobiological and photoelectrochemical methods.
Harvesting Hydrogen from Natural Gas
Hydrogen can be harvested from the methane found in natural gas. The process is referred to as steam methane reforming and is used to produce approximately 95 percent of the hydrogen used in the United States today. An alternative method is called partial oxidation which harvests the hydrogen by bruning methane in the air. Each of these methods creates a synthesis gas that is then reacted with water in order to produce even more hydrogen.

Renewable Electrolysis and Gasification

The electrolysis method of hydrogen harvesting makes use of electric current in order to split water into oxygen and hydrogen. An even greener manner of this type of harvesting is to use an alternative energy source such as solar, geothermal, hydroelectric, or wind in order to produce the energy used in the harvesting process.

Gasification is the hydrogen producing process that uses coal or biomass and applies heat while putting the substance under pressure with steam present. A number of chemical reactions then occur which produces a synthesis gas that is then combined with the steam in order to produce additional hydrogen. Using this method is more efficient than directly burning coal to harvest hydrogen. Researchers continue to work on new methods to separate and store the carbon dioxide that is produced in the currently used process in order to reduce the greenhouse gas emissions that currently result from gasification.

What Are the Barriers to Hydrogen Harvesting?

The largest barrier to wide-spread hydrogen harvesting for energy use is reducing the cost of the harvesting process and transportation. The goal of research and development is to reduce the cost of a gallon of gasoline equivalent of hydrogen to approximately $2 to $3 USD before tax. Current technology is not quite there yet, but photobiological and photoelectrochemical harvesting techniques are still in the early stages of research and may have the most potential to be the cheapest and cleanest means of hydrogen harvesting for use in fuel cell technologies as an alternative energy source.

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How Does a Fuel Cell Work?

A single hydrogen fuel cell is an electrolyte that is placed between two electrodes, has an anode, and a cathode. There are bipolar plates located on each side of the fuel cell that serve as collectors of the current produced by the cell and help spread out the gases produced during the energy extraction process.

Polymer Electrolyte Membrane Fuel Cell

The PEM fuel cell is the most researched of the varieties of fuel cells for propulsion of vehicles. In this design, hydrogen gas is channeled to the cell anode where a catalyst is used to separate the hydrogen molecules into electrons and protons. The membrane then only allows protons to pass through it to the other side of the cell. At the same time, the electrons follow an external circuit to the cathode section of the cell and is the electricity that is produced by the cell. On the opposite side of the fuel cell, oxygen gas is channeled to combine with the electrons that creates heat from an exothermic reaction that can be used external to the fuel cell.

All hydrogen fuel cells to date have consisted of two electrodes and an electrolyte. The different classifications of cells is based on the type of electrolyte used in the cell. Different ones will result in a variance in chemical reaction within the call and temperatures produced by the fuel cell.

What Are Some Hydrogen Fuel Cell Applications?

Hydrogen fuel cells have been looked at for a variety of power options. Some of these include use in stationary power stations for remote power backup, distributed power generation, and cogeneration. On the smaller scale, miniature hydrogen fuel cell research has focused on being able to replace traditional batteries in order to provide power for portable devices and small generators. Probably the most well-known use of fuel cells has been as an alternate power source for automobiles and marine engine replacements.

Why Should We Develop and Use Hydrogen Fuel Cells?

Since hydrogen fuel cells directly convert the chemical energy stored in hydrogen to electricity with water and heat as the only waste products, it is significantly more friendly to the environment. Fuel cells also have been shown to have up to three times the efficiency of fossil fuel combustion. For example, the engine in your car is at most 20 % efficient when converting the energy potential of gasoline where an equivalent hydrogen fuel cell would be between 40 and 60 percent efficient. Fuel cells also require less machinery to use for conversion to power than a traditional gasoline-based engine and would require 2 to 3 times less the equivalent volume of fuel that a gasoline-powered car does.

Barriers to Adopting Hydrogen Fuel Cell Technology

The most significant barriers to wide-spread adoption of hydrogen fuel cell technology as a green energy source is the reduction of cost and improvements in the durability of fuel cell systems. At the time of this writing, fuel cell systems were still not cost-competitive with fossil fuel based propulsion systems. Current research in fuel cell technologies remains focused on trying to find new materials that will help reduce the cost of fuel cells and improve the durability of fuel cell systems.