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:
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.
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 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.
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:
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:
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:
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.
Return to American Hydrogen Association Home Page
Contact 123GoH2@gmail.com for more information about AHA