Realities of The Hydrogen Economy
Copyright © 2002, 2003, Laramie Crocker
The Free Lunch
In the January 28, 2003 State of the Union Address, President George W. Bush
said he wanted to spend
Back to 2003. Hydrogen as a transportation medium seems pretty clean right now. We don't know the long term effects or the actual working efficiencies or the byproducts released with mass use. But even the cleanest source of energy we have, hydroelectric, has vast environmental impact through dams and electric grids. Near term, Hydrogen will move energy produced by the current mix -- gas, oil, coal, hydroelectric, nuclear, wind, solar, geothermal. Each of these contributes to environmental degradation, global warming, etc. Greater efficiency and less local pollution or even less total lifecycle pollution would be possible, and would be welcomed. The energy lifecycle includes manufacture and disposal of the fuel cells themselves, too. We also have to ask the cost of the hydrogen economy on society and the economy at large. Will this represent more concentration of centralized energy brokerage? More control of the people's resources? More control of essential economic power? What about shifts in economic power bases.
Energy Conversion, Production, Consumption
Energy is neither created nor destroyed, only transformed. Even Nuclear Energy is energy in one form (mass) transformed into its energy equivalent (energy), E=mc^2 as you recall.
But some devices are more energy conversion-y than others. We think of burning chemical energy and transforming it into heat and thence into motion via an engine or cycle (Brayton cycle -- jet engine, Sterling cycle -- steam engine, etc.) as "producing energy", whereas it is really just energy conversion. But this is really in terms of the resource and the resource lifecycle. So fossil fuels are seen as a raw resources -- "free" for the taking, once you have kicked the Indians off the land, bombed the "terrorists" off the land, placated those pesky tundra-huggers, etc. Hydropower is seen as a raw resource, too, since the Sun did the heavy lifting. Solar is a raw resource. Ditto geothermal and nuclear. We have to pay dollar and environmental costs, but so far the extraction cost doesn't outstrip the value of most of these. Solar is still loosing to high capital costs, etc. (Although the capital costs for solar come jumping down every year.)
We view electric motors as energy conversion devices, since they take a processed, high grade form of energy and convert it into work (motion, which is not work, but you know what I mean -- kinetic energy). Compressed air would be in this category, too, as would pumped hydro-electric (water that is pumped uphill during low periods, and allowed to flow back downhill through turbines and generate electricity during peak demand hours.)
Hydrogen is really in this second camp -- more energy conversion than energy source. We don't mine hydrogen, or collect it pure from outer space (though we could do the latter, conceivably), or find pure hydrogen deposits, or hydrogen-rich compounds. We take H2O, and disassociate the elements by storing a lot of energy into the H2 molecule. H2 forms a single, covalent bond. That energy comes from electricity, which is used to separate the H2 from the O, and releases O2 and H2 via ionization.
energy + 2(H2O) ==> 2(H2) + O2The oxygen is freely available in the atmosphere, so we don't cart it around in the fuel cell. So we carry around the H2, either under pressure as pure gas, or under pressure and lowered temperature as a liquid, or in some other storage medium (i.e. some weak associative bonding with another material, perhaps). Then we combine the H2 with the available O2 in a high-temperature oxydation reaction (burning) or we use some electrochemical process in a fuel cell. Either way, the reaction is
2(H2) + O2 ==> energy + 2(H2O)so the byproducts are nice: energy and (hopefully) clean water. I have yet to see any mechanical device be 100% efficient, so other by-products may sneak in. For example, the O2 does not come from bottled Oxygen, but from the atmosphere, which has mostly N2, nitrogen, along with other trace gasses, including CO2. Nitrogen has the tendency to recombine at high combustion temperatures as NOx (NO, NO2 and other, more esoteric Nitrogen Oxides -- Nitric Oxide, Nitrous Oxide, and so on -- which are referred to as NOx compounds). A given mix of H2 and O2 may burn at 2800 degrees Centigrade, for example, this calculation shows combustion temperatures between 1000 and 3000 Kelvin, when burned with nitrogen. Similarly, CO2 may be transformed into CO or various CH groups (hydrocarbons).
It is also possible that a near-term source of H2 will be the direct conversion of Hydrocarbons to extract the Hydrogen. This is a very messy process, akin to just burning the stuff.
So where do you get the energy from in the first place? Ah, here's the rub: from the same places you get it now. So a fuel cell becomes a better battery. An energy storage device, not really an energy source or conversion device, although it is clearly an energy conversion device. But the use is to take centrally available energy, and efficiently carry it from place to place for decentralized consumption. (Conversion to lower grade energy that cannot be recouped, as dictated by the second law of thermodynamics -- road and air friction becomes heat, and lost brake energy does too. But this heat is so low temp that it cannot be recycled.)
So there is the possibility that the "back end" for the hydrogen car could be nuclear power plants. Or centralized coal buring power plants, or gas and oil plants like PG&E #7 in Pittsburg, CA.
Or, people could generate solar and wind and sell it through the grid and broker it to you to charge your fuel cell directly, at your home H2 generation station. There are many different economic models to choose from. Jeremy Rifkin has commented on some of these economies, and in his book, The Hydrogen Economy discusses possible use of the Internet to broker distributed, decentralized power generation by individuals. Given oil's history, don't underestimate the political, economic, and power issues that will come out. The oil and car companies are hot to dominate this market in the most tech-intensive way possible. They want centralized, high tech, since it is controllable. They are working on it, fighting for it right now. They are not stupid. They've been at this for a hundred years, they know the biz. It may be 50 years off, but it may be profitable and controllable in 5 to 10.
The fuel cells themselves are liable to be very complicated and possibly use heavy metals and other dangerous substances in their manufacture and use. See this DOE page on the challenges of producing actual fuel cells. Joe's Fixit Shop may not be able to service one. This is high tech. One big enough to power your car may cost in the thousands of dollars for quite some time. The cute little laptop ones will be affordable by 2003, 2004...? But no one services their laptop batteries now. And they are incredibly toxic. I'm envisioning something on those lines. This is what I mean by the fuel lifecycle. Then you have to get into issues we can't see. What is the net effect of dumping all this water in the air locally? Minimal? Maybe. What if the fuel cells are 99.9% pure, but leak, say, dioxin as you motor down the road as a byproduct. I'm not saying that is the case, but what if something like that turns out to be the cheapest way to make a fuel cell work? We tend to look on new technology with rose colored glasses. When nuclear energy was first being worked out, people thought that since the energy is so plentiful, that eventually it would cost more to maintain electricity meters than the actual energy itself, so electricity would simply be free to consumers! When X-Rays were first discovered, there were no known health side-effects, so you could go down to the local store and for a dime turn on the X-Ray, put your feet in a box, wiggle your toes, and watch your toe bones for minutes. Be very, very careful when someone says a new technology is without ramifications.
Conservation has been the single greatest renewable resource we have seen in the last decades. It has provided more energy than any other new resource. Our usage is so great, that a 10% conservation is like discovering a new Alaska (and all it's oil fields put together.) I'm a little rusty on the actual number, but one of my Professors at Berkeley, Arthur Rosenfeld, measured conservation figures in "Alaskas". That measure is even more important in the Dubya era. So what if there were affordable electric florescents that had daylight colors and didn't flicker and you could just use them, but they were 5 times the efficiency of incandescents? Well, they have them. What if everyone insulated their walls and windows? Turns out to pay most people in about 3 years. We have to have the economy set up so that that works for people. For most people, operating month to month, it doesn't. What if you could take a train anywhere you wanted to go? What if all TV's used LCD, which are much more efficient?
So you can still enjoy energy, but the devices must be better and must be amortized correctly. What if you didn't need to get in your car to go shopping or to work every day. etc. etc. I don't commute to work and my quality of life is very high. I drive a car every couple of days. Sometimes I go a week without driving. In Berkeley I rarely drive. In New York, I never drive. And I'm not giving anything up. I'm staying healthy on my bike, and happy on BART or the NYC subway. Americans need to shift attitudes about energy.
Although, as I write this in the cold Winter in Vermont, I burn a wheelbarrow-full of wood per day ...