Hydrogen

Introduction to Hydrogen Fuel


Hydrogen is the most abundant element in the universe. It burns cleanly with water vapor as the only combustion product, and has been touted by some as the energy source of the future. However, hydrogen is not a source of energy, but rather a way to store and transport energy. Pure hydrogen is not readily available in nature (it is so light that it can escape out of the atmosphere), so it must be manufactured from electricity or fossil fuels (about 96% of the hydrogen used in the US is made from natural gas).

If hydrogen is to be made from electricity through electrolysis, the power consumption is significant: one kilogram of hydrogen (the energy equivalent of one gallon of gasoline) contains 39 kW-hrs of energy, but losses in the electrolysis process mean that more energy must be used. A typical system requires about 55 kW-hrs of power. If this electricity were purchased at $.10 per kW-hr, the cost of producing one Kg of hydrogen is $5.50 for electricity costs alone. Compression costs must be added, as well as the capital costs of the electrolyzer and compressor. Evaluating these costs based on current demonstration projects gives estimates of between $10 to $40 per Kg of hydrogen, or about 3 to 12 times more expensive than current fuel costs. If this fuel is to be converted back to electricity, additional losses will occur, with the delivered electricity being only about 25-35% of the energy put into the system. Batteries are 50-80% efficient, and can be much simpler systems.


How does Hydrogen Energy Work?

hydrogen-fuel-cell.jpg

An example of a Hydrogen fuel cell.
(Image from Alternative Energy News)


If hydrogen is to be made from electricity through electrolysis, the power consumption is significant: one kilogram of hydrogen (the energy equivalent of one gallon of gasoline) contains 39 kW-hrs of energy, but losses in the electrolysis process mean that more energy must be used. A typical system requires about 55 kW-hrs of power. If this electricity were purchased at $.10 per kW-hr, the cost of producing one Kg of hydrogen is $5.50 for electricity costs alone. Compression costs must be added, as well as the capital costs of the electrolyzer and compressor. Evaluating these costs based on current demonstration projects gives estimates of between $10 to $40 per Kg of hydrogen, or about 3 to 12 times more expensive than current fuel costs. If this fuel is to be converted back to electricity, additional losses will occur, with the delivered electricity being only about 25-35% of the energy put into the system. Batteries are 50-80% efficient, and can be much simpler systems.

The ability to store energy is attractive in areas of Alaska with significant stranded renewable energy resources but limited energy loads to make use of them. This scenario describes much of the state, where there is a nearly limitless supply of wind, wave and tidal energy. Hydrogen might one day play a role in capturing that energy and transporting it to market. If this is ever to happen, very significant cost reductions and/or efficiency gains need to be made in the areas of producing, compressing, and storing hydrogen, or very high taxes on carbon imposed.


Hydrogen Power in Alaska

Hydrogen use as an energy source is found few and far between in Alaska. However, several projects do exist and are continuing development in using hydrogen as a viable fuel source. The Chena Hotsprings Hydrogen Fuel Project is an interesting look at innovative hydrogen power development in Alaska's unique environment.

Chena Hot Springs Resort is located about entirely off the grid about 60 miles from Fairbanks, Alaska. To produce power, the resort depends almost entirely on geothermal energy. However, the geothermal power plant that produces electricty for the resort is not designed to store excess energy during times of low usage; thus, some of the energy goes to waste. The owners of the hot springs have decided that to help offset this waste, they would generate hydrogen via electrolysis and use it as an additive to propane and for transportation purposes. Visit ACEP's project website (link above) to learn more.

chenahydrogen

Challenges in Hydrogen Power

Hydrogen has an extremely high energy content, but its energy density is very low, thus generally requiring pressurization for large-scale shipping and/or space-efficient storage, which adds costs and complication to the overall process. Currently, the most cost effective method of transportation is via pipeline; however suitable pipeline infrastructure is expensive. Hydrogen causes embrittlement of metals, increasing the likelihood of leakage over time. Nonetheless, development of hydrogen pipelines are increasing, both for oil refining and other chemical processes and as part of the natural gas pipeline infrastructure for storing otherwise stranded wind energy. These physical constraints with storing and shipping pure hydrogen have led to searches for alternative chemical and/or physical structures that include “clean” hydrogen but have more favorable commercial properties, including higher energy density, larger molecules, less leakage and less metal embrittlement1.


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