The answer is simple: The miracle cure might not be so miraculous. There is a limit to the achievements of the hydrogen economy. What is the hydrogen economy? To put it simply, it is the hypothetical situation where automotive power is derived from reacting hydrogen with oxygen. The purpose of the hydrogen economy is to reduce carbon dioxide emissions from carbon-based fuels and to provide a replacement for dwindling petroleum reserves. This would make it a storage tool as opposed to nuclear fusion as a primary energy source.We have to ask ourselves two questions, claims Kenneth Deffeyes. "Is hydrogen an effective solution to the problem?" and "Can we make an orderly transition from our present gasoline powered cars to a hydrogen fleet?" These can lead to two interesting problems. The first being a situation similar to that of ethanol. Ethanol, or corn oil, requires more energy input than that which is derived from the final product. If this is the case with hydrogen, then perhaps it is not so economical to utilize it as a fuel source.
The second issue is like that of natural gas powered vehicles. Is it a chicken and egg situation? Iceland has opened a hydrogen fueling station, but it is the only country to do so. Will other countries follow suit or will they wait until hydrogen cars are built? Will hydrogen cars be built if there are no filling stations? Governments can help the immediate situation by adding incentives if companies start producing and providing the necessary resources.
The biggest attraction of hydrogen energy is mobility. A large portion of petroleum is used for transportation. If we run out of petroleum, we lose a lot of transportation. But hydrogen can be used for a multitude of things. For example, according to a PBS article, Neah Power Systems in Seattle has developed a hydrogen battery which can provide power to laptops for up to 8 hours. If the technology advances, it could become efficient and powerful enough to power computers for far longer, or even to power automobiles. But most hydrogen today is used in making fertilizer and upgrading petroleum in refineries.
There are three ways of producing hydrogen known today. The first is known as the water-gas process. Put simply, it reacts methane (CH4) and steam (H2O) with a nickel catalyst at temperatures of 1500 °F. The end products are carbon dioxide (CO2) and hydrogen (H2).
CH4 + 2 H2O = CO2 + 4 H2
Natural gas is the easiest way to produce this hydrogen, being composed mainly of methane. However, in the absence of natural gas, coal is another option. If natural gas is used, it would be an economic cycle. The natural gas from oil wells could be used to produce hydrogen. Then the carbon dioxide waste could be used to recover more oil.
The second process is electrolysis. This method is accomplished by using electrolytic cells. These are cell which contain a cathode (positive) and anode (negative), using electrical voltage to separate ions. As with anything, however, there is a positive and negative side to producing hydrogen in this manner. The positive is that current (in amperes) produces hydrogen with over 98% efficiency. The downside, however, is that the voltage required is 20-30% greater than the ideal
What does this mean? Here's an example provided by Deffeyes in Beyond Oil. The most efficient commercial cells require 1.75-2.00 volts to produce hydrogen. The fuel cell only returns 0.7 volt. what does this mean? You only get back 40% of your overall volt input. But certainly we can develop a more efficient process! Theoretically, we can increase the efficiency by 30%, but the technology has stagnated. At the same time, solar and wind power can be used to produce hydrogen. However, these processes are not yet enough to compete with commercial electrolysis cells.
Finally, there are exotic hydrogen sources. Breaking down compounds which contain hydrogen works, but isn't done commercially. But the most interesting exotic source is purple bacteria. Instead of green chlorophyll, they have a different chemical compound which absorbs sunlight. Nothing is certain as of yet, but research in being conducted.
In the words of Nobel Prize-winning physicist Richard Smalley, "I believe it is the single most important problem facing humanity today: Energy. How are we going to get prosperous when oil and gas and coal are no longer enough?" The only way we can continue to prosper is by finding alternate sources of energy. Hydrogen is looking good, but there are definitely issues. If hydrogen power is to be completely non-polluting, the resources and methods used to produce it must also be non-polluting. There are also economic concerns about price. The final issues are, of course, storage and safety.
Hydrogen can be safely stored either as a pressurized gas or a cold liquid. Pressurized gas is stable, but large amounts of money are required to produce the necessary power. Liquid hydrogen, on the other hand, would require an insulated fuel cell and an escape route. With no escape route, the results could be... explosive. At current technological levels, liquid hydrogen is more efficient for consumption equivalent to 10 gallons of gasoline or greater. The major safety issue with hydrogen is that is burns. On its own, hydrogen gas isn't toxic if there is sufficient oxygen. But solutions of 4-75% hydrogen will burn. Hydrogen flames are nearly invisible and propagate at a rate of nearly 10ft/sec. Hydrogen can also undergo combustion in mixtures between 18-60% hydrogen. That mans absolutely no open flames near a hydrogen source unless it is very carefully controlled.
Overall, hydrogen seems like a good solution. But there are plenty of issues that need to be overcome before it is economically and commercially viable. So, what do we do? What are your thoughts on the matter?
The second process is electrolysis. This method is accomplished by using electrolytic cells. These are cell which contain a cathode (positive) and anode (negative), using electrical voltage to separate ions. As with anything, however, there is a positive and negative side to producing hydrogen in this manner. The positive is that current (in amperes) produces hydrogen with over 98% efficiency. The downside, however, is that the voltage required is 20-30% greater than the idealWhat does this mean? Here's an example provided by Deffeyes in Beyond Oil. The most efficient commercial cells require 1.75-2.00 volts to produce hydrogen. The fuel cell only returns 0.7 volt. what does this mean? You only get back 40% of your overall volt input. But certainly we can develop a more efficient process! Theoretically, we can increase the efficiency by 30%, but the technology has stagnated. At the same time, solar and wind power can be used to produce hydrogen. However, these processes are not yet enough to compete with commercial electrolysis cells.
Finally, there are exotic hydrogen sources. Breaking down compounds which contain hydrogen works, but isn't done commercially. But the most interesting exotic source is purple bacteria. Instead of green chlorophyll, they have a different chemical compound which absorbs sunlight. Nothing is certain as of yet, but research in being conducted.
In the words of Nobel Prize-winning physicist Richard Smalley, "I believe it is the single most important problem facing humanity today: Energy. How are we going to get prosperous when oil and gas and coal are no longer enough?" The only way we can continue to prosper is by finding alternate sources of energy. Hydrogen is looking good, but there are definitely issues. If hydrogen power is to be completely non-polluting, the resources and methods used to produce it must also be non-polluting. There are also economic concerns about price. The final issues are, of course, storage and safety.
Hydrogen can be safely stored either as a pressurized gas or a cold liquid. Pressurized gas is stable, but large amounts of money are required to produce the necessary power. Liquid hydrogen, on the other hand, would require an insulated fuel cell and an escape route. With no escape route, the results could be... explosive. At current technological levels, liquid hydrogen is more efficient for consumption equivalent to 10 gallons of gasoline or greater. The major safety issue with hydrogen is that is burns. On its own, hydrogen gas isn't toxic if there is sufficient oxygen. But solutions of 4-75% hydrogen will burn. Hydrogen flames are nearly invisible and propagate at a rate of nearly 10ft/sec. Hydrogen can also undergo combustion in mixtures between 18-60% hydrogen. That mans absolutely no open flames near a hydrogen source unless it is very carefully controlled.
Overall, hydrogen seems like a good solution. But there are plenty of issues that need to be overcome before it is economically and commercially viable. So, what do we do? What are your thoughts on the matter?
1 comment:
The short side of a battery symbol is negative. Current flow is from negative to positive. Cathode is negative, anode is positive.
Easy way to remember is cathode ray, tube. Not anode ray, tube.
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