How the Hydrogen Economy works

by Marshall Brian

Edited by Roy McAlister

It seems like every day there is a new announcement in the news about automobiles powered by fuel cells. The promises are tantalizing, since using hydrogen in existing engines can actually clean the air and fuel cells have the potential to increase the efficiency of cars while significantly reducing air pollution. At the same time, there have been news stories for decades about the problems associated with petroleum. Everything from oil spills to ozone depletion to global warming gets blamed on our dependence on fossil fuels. These two forces are leading the world toward what is broadly known as the hydrogen economy. If the predictions are true, over the next several decades we will all begin to see an amazing shift away from the fossil fuel economy we have today toward a much cleaner hydrogen future.

Can society actually make this shift, or will the technological, economic and political barriers keep us dependent on petroleum and other fossil fuels for the next century and beyond? In this article, you will learn about the benefits of a hydrogen economy, along with its potential problems. We will also examine some of the technology that would make the transition possible.

Problems with the fossil fuel economy
Currently, the United States and most of the world is locked into what could be called the fossil fuel economy. Our automobiles, trains and planes are fueled almost exclusively by petroleum products like gasoline and diesel. A huge percentage of our power plants use oil, natural gas and coal for their fuel. If the flow of fossil fuels to the United States were ever cut off, the economy would come to a halt. There would be no way to transport the products that factories produce. There would be no way for people to drive to work. The whole economy, and in fact the whole of western society, currently depends on fossil fuels. While fossil fuels have played an important role in getting society to the point it is at today, there are four big problems that fossil fuels create:

Air pollution - When cars burn gasoline, they would ideally burn it perfectly and create nothing but carbon dioxide and water in their exhaust. Unfortunately, the internal combustion engine is not perfect. In the process of burning the gasoline, it also produces:
- Carbon monoxide, a poisonous gas
- Nitrogen oxides, the main source of urban smog
- Unburned hydrocarbons, the main source of urban ozone

Catalytic converters eliminate much of this pollution, but they aren't perfect. Air pollution from cars and power plants is a real problem in big cities.

Environmental pollution - The process of transporting and storing oil has a big impact on the environment whenever something goes wrong. An oil spill, pipeline explosion or well fire can create a huge mess. The Exxon Valdez spill is a well-known example of the problem, but minor spills happen constantly.

Global warming - When you burn a gallon of gas in your car, you emit about 20 pounds of carbon dioxide into the atmosphere. If it were solid carbon, it would be extremely noticeable -- it would be like throwing a 5-pound bag of sugar out the window of your car for every gallon of gas burned. But because the 5 pounds of carbon comes out as 20 pounds of invisible carbon dioxide gas, most of us are oblivious to it. The carbon dioxide coming out of every fossil fired power plant and car's tailpipe is a greenhouse gas that is slowly raising the temperature of the planet. The ultimate effects are unknown, but it are strong indications that we are experiencing dramatic climate changes that affect everyone on the planet. For example, melting glaciers and polar ice caps raise the sea level, causing flooding of coastal cities. Fresh water dilution of the polar ocean waters can cause the sea currents to change. That's a big side effect that could cause Iceland, Ireland, England and France to experience much cooler weather. Similar changes would be expected for northern areas of both coasts of North America.
Dependence - The United States, and most other industrialized countries, cannot produce enough oil to meet demand, so they import it from oil-rich countries. That creates an economic dependence. When Middle East oil producers decide to raise the price of oil, the rest of the world has little choice but to pay the higher price.

Advantages of the hydrogen economy
In the previous section we noted the significant, worldwide problems created by fossil fuels. The hydrogen economy promises to eliminate all of the problems that the fossil fuel economy creates. Therefore, the advantages of the hydrogen economy include:

The elimination of pollution caused by fossil fuels - When hydrogen is used in a heat engine or fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen.
The elimination of greenhouse gases - If the hydrogen comes from the electrolysis of water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle -- electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell.
The elimination of economic dependence - The elimination of oil means no dependence on the Middle East and its oil reserves.
Distributed production - Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology.

The problems with the fossil fuel economy are so great, and the environmental advantages of the hydrogen economy so significant, that the push toward the hydrogen economy is very strong.

Technological Hurdles
The big question with the hydrogen economy is, "Where does the hydrogen come from?" After that comes the question of transporting, distributing and storing hydrogen. Hydrogen tends to be bulky and in its natural gaseous form.

Once both of these questions are answered in an economical way, the hydrogen economy will be in place.

We'll look at each of these questions separately in the following sections.

Where does the hydrogen come from?
One of the more interesting problems with the hydrogen economy is the hydrogen itself. Where will it come from? With the fossil fuel economy, you simply pump the fossil fuel out of the ground and refine it. Then you burn it as an energy source. Most of us take oil, gasoline, coal and natural gas for granted, but they are actually quite miraculous. These fossil fuels represent stored solar energy from millions of years ago. Millions of years ago, plants grew using solar energy to power their growth. They died, and eventually a small fraction of this biomass turned into oil, coal and natural gas. When we pump oil from the ground, we tap into that huge solar energy storehouse without paying the replacement price. Whenever we burn a gallon of gasoline, we release stored solar energy. In the hydrogen economy, there is no storehouse to tap into. We have to actually create the energy in real-time.

There are numerous possible sources for the hydrogen such as:

Electrolysis of water - Using electricity, it is easy to split water molecules to create pure hydrogen and oxygen. One big advantage of this process is that you can do it anywhere. For example, you could have a box in your garage producing hydrogen from tap water, and you could fuel your car with that hydrogen.
Reforming organic substances - Oil and natural gas contain hydrocarbons -- molecules consisting of hydrogen and carbon. Using a device called a fuel processor or a reformer, you can split the hydrogen off the carbon in a hydrocarbon relatively easily and then use the hydrogen. Reformers discard the leftover carbon to the atmosphere as carbon dioxide. This option is, of course, slightly perverse. You are using fossil fuel as the source of hydrogen for the hydrogen economy. This approach reduces air pollution, but it doesn't solve either the greenhouse gas problem (because there is still carbon going into the atmosphere) or the dependence problem (you still need oil). However, it may be a good temporary step to take during the transition to the hydrogen economy. When you hear about "fuel-cell-powered vehicles" being developed by the car companies right now, almost all of them plan to get the hydrogen for the fuel cells from gasoline using a reformer. The reason is because gasoline is an easily available source of hydrogen. Until there are "hydrogen stations" on every corner like we have gas stations now, this is the easiest way to obtain hydrogen to power a vehicle's fuel cell.
Reforming biomass - If the organic substance is sewage, garbage, agricultural wastes, or forest slash however releasing the hydrogen and venting the carbon dioxide is no worse than the natural result of having such wastes rot or burn into the atmosphere.
Pyrolysis: Another technology for producing hydrogen is to break organic molecules into hydrogen and carbon. An oxidant free chamber can be heated to sufficient temperature to break hydrogen away from carbon and allow the carbon to be sequestered to build better solar collectors, wind and wave turbines, and wave machines for harnessing more renewable energy.

The interesting thing about these comparisons is that there are numerous ways to supply the hydrogen needed. To have a sustainable hydrogen economy, the hydrogen must be derived from renewable sources rather than fossil fuels so that we stop changing the atmosphere with carbon particles and gases. Having enough electricity to separate hydrogen from water, and generating that electricity without using fossil fuels, will be the biggest change that we see in creating the hydrogen economy.

Where will the electricity for the electrolysis of water come from? Right now, about 68 percent of the electricity produced in the United States comes from coal or natural gas. All of that generating capacity will have to be replaced by renewable sources in the hydrogen economy. In addition, all of the fossil fuel energy now used for transportation (in cars, trucks, trains, boats, planes) will have to convert to hydrogen, and much of that hydrogen will be created with electricity, as well. But it is possible to use hydrogen in engine-generators with heat recovery systems to double the energy utilization efficiency of conventional power plants.

Right now there are several different ways to create electricity that do not use fossil fuels:

Nuclear power
Hydroelectric dams
Solar cells
Wind turbines
Geothermal power
Wave and tidal power
Co-generation (For example, a sawmill might burn bark to create power, or a landfill might burn methane that the rotting trash produces.)

In the United States, about 20 percent of the power currently comes from nuclear and 7 percent comes from hydroelectric. Solar, wind, geothermal and other sources generate only 5 percent of the power. Nuclear power have waste disposal, potential terrorist dirty bomb problems along with political problems. Nuclear plants require enormous subsidization, long lead times and 15 or more years of operation to provide energy payback of fossil resources used to mine, refine, and construct the massive power plants needed. Carbon dioxide and other fossil emissions required to prime the nuclear power pump comes first then after a long time there may or may not be an energy payback. Wind, wave and solar power systems currently have cost and location problems.

In the future, barring some technological breakthrough, it seems likely that one of two things will happen to create the hydrogen economy: Either nuclear-power or various forms of solar, wind, and wave power generating capacity will increase dramatically.

Hydrogen production is probably the biggest hurtle for the hydrogen economy. Once the technology is refined and becomes inexpensive, hydrogen engines and fuel-cells will power farms, vehicles, homes, and factories.

How do you store and transport the hydrogen?
At this moment, the problem with putting pure-hydrogen vehicles on the road also encounters the storage/transportation problem. Hydrogen is a bulky gas, and it is not nearly as familiar to work with as gasoline. Compressing the gas requires energy, and moderately compressed hydrogen contains far less energy than the same volume of gasoline. However, solutions to the hydrogen storage problem are surfacing.

For example, hydrogen can be stored in a solid form in hydrides and in chemicals such as a chemical called sodium borohydride, and this technology has appeared in the news because Chrysler is testing it. This chemical is created from borax (a common ingredient in some detergents). As sodium borohydride releases its hydrogen, it turns back into borax so it can be recycled.

Once the storage problem is solved and standardized, then a network of hydrogen stations and the transportation infrastructure will have to develop around it. The main barrier to this might be the technological sorting-out process. Stations will not develop quickly until there is a storage technology that clearly dominates the marketplace. For instance, if all hydrogen-powered cars from all manufacturers used sodium borohydride, then a station network could develop quickly; that sort of standardization is unlikely to happen rapidly, if history is any guide.

There might also be a technological breakthrough that could rapidly change the playing field. For example, if someone could develop an inexpensive rechargeable battery or practical flywheel propulsion system with high capacity and a quick recharge time, electric cars would not need fuel cells and there would be no need for hydrogen on the road. Cars would recharge using electricity directly but it would be preferable for the electricity to be produced from renewable resources in part by hydrogen cogeneration systems that double the energy utilization efficiency of conventional power plants.

Prospects for the future
You will hear more and more about the hydrogen economy in the news in the coming months, because the drumbeat is growing louder. The environmental problems of the fossil fuel economy are combining with breakthroughs in fuel-cell technology, and the pairing will allow us to take the first steps.

The most obvious step we will see is the marketing of fuel-cell-powered vehicles. Although they will be powered initially by gasoline and reformers, fuel cells embody two major improvements over the internal combustion engine:

Fuel cells may be about twice as efficient in some applications but this is also true of diesel engines converted to hydrogen compared to present gasoline engines.
Converted internal combustion engines and fuels cells can significantly reduce air pollution in cities.

Gasoline-powered fuel-cell vehicles are an excellent transitional step because of those advantages.

Moving to a pure hydrogen economy will be harder. The power-generating capacity will have to be switched to renewable sources of energy, and the marketplace will have to agree on ways to store and transport hydrogen. These hurdles mean that many new jobs will be created as we convert the fossil fueled Industrial Revolution to the Sustainable Prosperity Revolution.

End

Return to American Hydrogen Association Home Page

Contact 123GoH2@gmail.com for more information about AHA