- Email: [email protected]
Hydrogen—the case for inevitability
Available online at www.sciencedirect.com
International Journal of Hydrogen Energy 29 (2004) 225 – 227
www.elsevier.com/locate/ijhydene
Hydrogen—the case for inevitability In which we nd the road to sustainability runs straight to hydrogen.
Skewering unful(lled predictions is easy. So, as I increasingly became aware of the patterns that, it seemed to me, were surely taking us to a hydrogen age, I was cautious of prediction, mindful of skewers. Yet as the realities and logic stacked up, it became di,cult to escape the conclusion that civilization had to evolve toward a hydrogen age—unless it self-destructed (rst. So I’ll set out the logic that, for me, became impossible reject. I (rst heard of hydrogen 1 in 1978 when, like just about everybody, I believed depletion would be the ultimate driver of energy system evolution. I had travelled to Ottawa to meet with Dr. Phillip Cockshutt. Phil was then Director of Energy Studies at the National Research Council of Canada (NRCC). And I, as a young Chair of Mechanical Engineering at the University of Toronto, hoped to learn why our department’s energy research proposal had failed to be funded. (My visit would remind me, again, that we often learn more from failures than successes.) I had not previously met Phil. He had graduated from Toronto in mechanical engineering and then gone to the Massachusetts Institute for Technology for his doctorate before returning to Canada and CNRC. I hoped he would be pleased to give counsel to his undergraduate alma mater. In style, I found Phil to be a Canadian version of (what we like to imagine as) a soft-spoken, understating, English country gentleman. We sat in his o,ce while he scratched out a network of energy options on his blackboard. I hadn’t yet realized the importance of thinking in terms of energy systems—to me they were still simply options. Phil explained many wondrous things, from “clever bugs that could be trained to eat shit and produce methane”—he has a gentle, poetic, yet pithy way to explain things—to something called hydrogen. I found three things about hydrogen intriguing. First, energy from any source can be used to make hydrogen by splitting water. Second, the exhaust from using hydrogen is water. Third—and this was a deeper, less obvious idea—hydrogen is the ideal fuel for fuelcells. I returned to Toronto thinking hydrogen was a “sweet” fuel. But since I was yet to conceive the idea of energy currencies, I could not slot hydrogen into its profound systemic signi(cance. I now look back at those times as a series of accidents that launched the voyage that was to be my karma. Two specters haunt 21st century energy system development. The (rst is the depletion of high-quality fossil fuels, most importantly oil, which is an especially vivid specter in the most oil-addicted nations. The second is the prospect of unprecedented economic, cultural and environmental disruption triggered by the system’s atmospheric eCuents. If our energy systems remain dominated by fossil fuels, it is merely a question of when, not if, one or both specters become cruel reality. I’m persuaded that climate disruption will materialize (rst. Which means fossil fuels are capped by the global environmental, not depletion—although Daring geopolitics could surely, and suddenly, crash upon us to bring a virtual depletion. Still whichever scenario arrives (rst, the shock of having to rapidly wean civilization from fossil fuels will occur well before the end of this century, almost certainly before mid-century—and probably within the next two decades. Depletion-based rationale for H2 inevitability In 1980, 2 years after Phil wrote “hydrogen” on the blackboard, I was invited to join a panel at the second World Hydrogen Energy Conference in Tokyo. Although I knew of the CO2 threat, I had not yet broken out from thinking 1
I mean hydrogen as a fuel for things like cars, trucks or airplanes. Anyone who took high school chemistry will remember their teacher using electrolysis to show that water was made of components, H2 and O2 —which usually led to some prank involving a small explosion or two. By the mid-1970s anyone interested in the space race knew the main rockets were fuelled by hydrogen and oxygen that, as it turns out, were precursors to our hydrogen future. 0360-3199/$ 30.00 ? 2003 Published by Elsevier Ltd on behalf of the International Association for Hydrogen Energy. doi:10.1016/S0360-3199(03)00126-5
226
D.S. Scott / International Journal of Hydrogen Energy 29 (2004) 225 – 227
depletion would be the most important a cap on fossil fuels. So my contribution to the discussion was a (ve-step “case for inevitability” based on depletion. The logic went something like this: 1. Driven by depletion, civilization must move from fossil to sustainable energy sources. 2. Today, chemical fuels (which power transportation) are harvested exclusively from fossil sources. 3. Therefore, we must be able to harvest our sustainable sources to provide chemical fuels. 4. Realistically, the only way sustainable sources can be harvested to make chemical fuels is via hydrogen. (How else can we get the energy from wind, solar or nuclear power to fuel an airplane?) 5. Therefore, the move from fossil to sustainable sources can only begin with increased use of H2 and can only be completed with the supremacy of H2 among chemical fuels. With this (ve-step rationale we’re bequeathed a straightforward, easy-to-remember logic. Yet the gift comes at a price. Some points beg further explanation, which we’ll begin next. Begin only, because it’s clearly an open-ended mission. Nevertheless, let’s start adding meat. The (rst step of the depletion rationale needs no comment. It’s the premise. We’ve discussed it before and will again. Moreover because it’s such a simple idea, depletion is a media staple. The second step is also straightforward: the kerosene for aircraft, the gasoline (petrol) and diesel for automobiles, trucks and trains, and the bunker C for ships, can now only be produced from fossil sources. The third step follows directly from the second; we must have a way to manufacture transportation fuels from our non-carbon, sustainable sources. Let’s say it with example: We must have a way for sunlight, wind, hydraulic or nuclear sources to ,y airplanes. The fourth step is that, by splitting water, any non-fossil source can be used to manufacture H2 , which can be used to fuel transportation. Moreover, no other fuel can as readily serve this global role. The (fth step is the only conclusion possible. Because the fourth step is probably the least obvious—the most di,cult to accept without a lot of pondering—let’s dig deeper. Perhaps I’m slower than many. But it took me many months to accept that H2 was unique. It seemed right. Yet I needed to check “seemed”. First I read a lot. Then I began asking informed people around the world: “Can you think of anything else that might meet the requirement?” No one gave me a credible alternative. Perhaps ammonia (NH3 ) came closest. But why use ammonia when you can use hydrogen? Ammonia requires that you (rst make hydrogen and then tie it to nitrogen. Ammonia is prickly stuL—have you ever got a whiL? And to make ammonia we must add nitrogen to hydrogen, which means ammonia is a much heavier fuel—in times when a key design strategy for e,cient vehicles is weight reduction. 2 Later, after I’d come to accept that hydrogen seemed to be the only clear option, I began being invited to give public lectures and to serve on task forces. On each occasion, I’d ask the audience (or fellow committee members): Can you think of anything other than hydrogen that could ful(ll this role? No realistic proposals came back. It was troubling. I disliked the idea of saying something was inevitable, hoped for an alternative that would allow me to be less absolute, less strident, less vulnerable to skewers. During these times, I also grew uneasy when people referred to hydrogen as an energy source—rather than something that allowed any source to power transportation (where is was most needed). My craving to clarify—to get things straight in my own head—led to the idea of “currencies”. It seemed we were missing the systemic role of hydrogen because we had no linguistic way to diLerentiate sources from (what I would come to call) currencies. “Running out” was the worry-of-the-day; (nding new sources to replace the old, the obsession. No one asked, “If we develop a new non-fossil energy source, how can we use it to Dy airplanes?” Moreover, the need for hydrogen reaches beyond transportation fuels. In setting out the second step in our rationale, a reality that could have been included, but wasn’t, is that fossil fuels also provide many of our material feedstocks—from building materials, to automobile, airplane and computer parts, to clothing and to supplement some foodstuLs. Moreover, even when the material itself contains nothing from the fossil source, fossil fuels are often still used to produce the materials. Steel, for example. Chemically, iron ore is Fe2 O3 . Today we use carbon to rip oxygen oL iron ore thereby leaving iron. A simple chemical-balance equation describes today’s process: 2Fe2 O3 + 3C → 4Fe + 3CO2 : This equation shows why CO2 is the principal (albeit invisible) eCuent from today’s steel making processes—thereby contributing to climate destabilization. But in the future we will be able to use hydrogen to do the ripping when the 2
The single advantage of ammonia over hydrogen is that ammonia can be more easily carried as a liquid. (It can also be directly used as a fertilizer.)
D.S. Scott / International Journal of Hydrogen Energy 29 (2004) 225 – 227
227
process equation becomes Fe2 O3 + 3H2 → 2Fe + 3H2 O: This time water is the eCuent and steel mills become better neighbors. Using hydrogen rather than carbon to manufacture materials—especially to reduce ores—involves more sophisticated ideas than simply using it as a fuel. So we’ll return to these ideas later. For now, let’s keep it simple. Let’s just remember: If we want to use the energy from windmills to Dy airplanes, then the windmills must manufacture hydrogen for H2 -fuelled airplanes. Nothing else makes sense. Climate-based rationale for H2 inevitability The maldistribution of global resources, the lower quality of hydrocarbon dregs, the risk of geopolitically triggered virtual depletion—and the price shocks that resulted—means depletion cannot be dismissed. Yet in an absolute sense, a diLerent, irrepressible force will overtake depletion as the reason to quit fossil fueling. That force will be the clear, immediate danger of catastrophic climate disruption. So let’s set out a second, (ve-step case for H2 age inevitability, this time based on climate disruption. 1. Atmospheric CO2 growth is bringing climate destabilization that, if unabated, will be catastrophic. 2. To eliminate anthropogenic CO2 emissions we require both non-carbon-emittingsources and non-carbon-carrying currencies. 3. There are many non-CO2 sources. 4. But realistically, electricity and hydrogen are the only two non-C currencies that together can supply the full menu of energy services. 5. Therefore, anthropogenic CO2 emissions can only be slowed by the extensive use of hydrogen and can only be stopped with the supremacy of sustainable-derived H2 among chemical fuels. Once again, by presenting this rationale in (ve steps we’re bequeathed a straightforward, easy-to-remember logic. And once again some points require further explanation. The (rst step in our rationale is simply the premise that climate destabilization, if unabated, will be catastrophic. The basis of this premise was introduced in earlier articles. But since it’s probably the greatest, yet most under-accepted risk facing 21st century civilization, we’ll return to climate destabilization in a later article in this series. The key point of the second step is also simple: We need more than non-carbon sources—we also require non-carbon currencies. Indeed, non-C currencies are even more important. I’ll explain why. If we use fossil fuels in stationary settings, it’s conceivable we could avoid the CO2 emissions if we could catch, then process and later sequester the carbon. 3 But how could we catch and sequester the CO2 eCuent from airplanes—or cars? Do we think aircraft could drag CO2 catching sacks behind them while these airplanes hurtle through the sky, (ve miles high, at speeds approaching that of sound—like the fen dou (manure-catching bags) I saw slung beneath horse’s tails as they clip-clopped through Beijing in the 1980s? The third step reminds us that we have many non-carbonaceous sources—from the windmills we’ve been talking about, to falling water, sunlight, nuclear power and so on. The fourth step of this logic names both electricity and hydrogen. From the beginning it has been clear that both currencies will be needed. Hydrogen alone cannot provide the full menu of services, just as today electricity can’t do everything. The hydrogen age won’t terminate electricity. Rather it will give electricity a wonderful new partner—a kindred spirit. It’s why I often speak, not of a coming hydrogen age, but of a coming hydrogen and electricity age. We’ll talk more of how hydrogen and electricity will work together in the next article of this series, “For Better or Worse.” Finally, we get to the (fth of this (ve-step case for inevitability. So obvious it’s anticlimactic. We’ve now come to a place from which we can see civilization’s inevitable future—at least the future of its energy system. And because the energy system underpins so much, it allows us to see much of everything else. Of course this inevitability assumes we achieve sustainability. If we don’t, civilization won’t have a future. Take your pick. This is the twenty-ninth in a series of articles by David Sanborn Scott Institute for Integrated Energy System, University of Victoria, Victoria, BC, Canada V8W 2Y2 E-mail address: [email protected] (D.S. Scott). 3 Today some fossil industries promote this approach. It can be entertaining to watch such entirely predictable pattern: threatened industries clawing at the past, rather than using their creative juices to exploit the future. At the best, carbon sequestering will be transitional technologies that might slow the inevitable decline of the fossil industry—but not by much. All such proposals fall into the category of “adding collectors” rather than “changing the process” that we discussed in the sixth article of this series, “From Oil Lamps to Lightbulbs”.
International Journal of Hydrogen Energy 29 (2004) 225 – 227
www.elsevier.com/locate/ijhydene
Hydrogen—the case for inevitability In which we nd the road to sustainability runs straight to hydrogen.
Skewering unful(lled predictions is easy. So, as I increasingly became aware of the patterns that, it seemed to me, were surely taking us to a hydrogen age, I was cautious of prediction, mindful of skewers. Yet as the realities and logic stacked up, it became di,cult to escape the conclusion that civilization had to evolve toward a hydrogen age—unless it self-destructed (rst. So I’ll set out the logic that, for me, became impossible reject. I (rst heard of hydrogen 1 in 1978 when, like just about everybody, I believed depletion would be the ultimate driver of energy system evolution. I had travelled to Ottawa to meet with Dr. Phillip Cockshutt. Phil was then Director of Energy Studies at the National Research Council of Canada (NRCC). And I, as a young Chair of Mechanical Engineering at the University of Toronto, hoped to learn why our department’s energy research proposal had failed to be funded. (My visit would remind me, again, that we often learn more from failures than successes.) I had not previously met Phil. He had graduated from Toronto in mechanical engineering and then gone to the Massachusetts Institute for Technology for his doctorate before returning to Canada and CNRC. I hoped he would be pleased to give counsel to his undergraduate alma mater. In style, I found Phil to be a Canadian version of (what we like to imagine as) a soft-spoken, understating, English country gentleman. We sat in his o,ce while he scratched out a network of energy options on his blackboard. I hadn’t yet realized the importance of thinking in terms of energy systems—to me they were still simply options. Phil explained many wondrous things, from “clever bugs that could be trained to eat shit and produce methane”—he has a gentle, poetic, yet pithy way to explain things—to something called hydrogen. I found three things about hydrogen intriguing. First, energy from any source can be used to make hydrogen by splitting water. Second, the exhaust from using hydrogen is water. Third—and this was a deeper, less obvious idea—hydrogen is the ideal fuel for fuelcells. I returned to Toronto thinking hydrogen was a “sweet” fuel. But since I was yet to conceive the idea of energy currencies, I could not slot hydrogen into its profound systemic signi(cance. I now look back at those times as a series of accidents that launched the voyage that was to be my karma. Two specters haunt 21st century energy system development. The (rst is the depletion of high-quality fossil fuels, most importantly oil, which is an especially vivid specter in the most oil-addicted nations. The second is the prospect of unprecedented economic, cultural and environmental disruption triggered by the system’s atmospheric eCuents. If our energy systems remain dominated by fossil fuels, it is merely a question of when, not if, one or both specters become cruel reality. I’m persuaded that climate disruption will materialize (rst. Which means fossil fuels are capped by the global environmental, not depletion—although Daring geopolitics could surely, and suddenly, crash upon us to bring a virtual depletion. Still whichever scenario arrives (rst, the shock of having to rapidly wean civilization from fossil fuels will occur well before the end of this century, almost certainly before mid-century—and probably within the next two decades. Depletion-based rationale for H2 inevitability In 1980, 2 years after Phil wrote “hydrogen” on the blackboard, I was invited to join a panel at the second World Hydrogen Energy Conference in Tokyo. Although I knew of the CO2 threat, I had not yet broken out from thinking 1
I mean hydrogen as a fuel for things like cars, trucks or airplanes. Anyone who took high school chemistry will remember their teacher using electrolysis to show that water was made of components, H2 and O2 —which usually led to some prank involving a small explosion or two. By the mid-1970s anyone interested in the space race knew the main rockets were fuelled by hydrogen and oxygen that, as it turns out, were precursors to our hydrogen future. 0360-3199/$ 30.00 ? 2003 Published by Elsevier Ltd on behalf of the International Association for Hydrogen Energy. doi:10.1016/S0360-3199(03)00126-5
226
D.S. Scott / International Journal of Hydrogen Energy 29 (2004) 225 – 227
depletion would be the most important a cap on fossil fuels. So my contribution to the discussion was a (ve-step “case for inevitability” based on depletion. The logic went something like this: 1. Driven by depletion, civilization must move from fossil to sustainable energy sources. 2. Today, chemical fuels (which power transportation) are harvested exclusively from fossil sources. 3. Therefore, we must be able to harvest our sustainable sources to provide chemical fuels. 4. Realistically, the only way sustainable sources can be harvested to make chemical fuels is via hydrogen. (How else can we get the energy from wind, solar or nuclear power to fuel an airplane?) 5. Therefore, the move from fossil to sustainable sources can only begin with increased use of H2 and can only be completed with the supremacy of H2 among chemical fuels. With this (ve-step rationale we’re bequeathed a straightforward, easy-to-remember logic. Yet the gift comes at a price. Some points beg further explanation, which we’ll begin next. Begin only, because it’s clearly an open-ended mission. Nevertheless, let’s start adding meat. The (rst step of the depletion rationale needs no comment. It’s the premise. We’ve discussed it before and will again. Moreover because it’s such a simple idea, depletion is a media staple. The second step is also straightforward: the kerosene for aircraft, the gasoline (petrol) and diesel for automobiles, trucks and trains, and the bunker C for ships, can now only be produced from fossil sources. The third step follows directly from the second; we must have a way to manufacture transportation fuels from our non-carbon, sustainable sources. Let’s say it with example: We must have a way for sunlight, wind, hydraulic or nuclear sources to ,y airplanes. The fourth step is that, by splitting water, any non-fossil source can be used to manufacture H2 , which can be used to fuel transportation. Moreover, no other fuel can as readily serve this global role. The (fth step is the only conclusion possible. Because the fourth step is probably the least obvious—the most di,cult to accept without a lot of pondering—let’s dig deeper. Perhaps I’m slower than many. But it took me many months to accept that H2 was unique. It seemed right. Yet I needed to check “seemed”. First I read a lot. Then I began asking informed people around the world: “Can you think of anything else that might meet the requirement?” No one gave me a credible alternative. Perhaps ammonia (NH3 ) came closest. But why use ammonia when you can use hydrogen? Ammonia requires that you (rst make hydrogen and then tie it to nitrogen. Ammonia is prickly stuL—have you ever got a whiL? And to make ammonia we must add nitrogen to hydrogen, which means ammonia is a much heavier fuel—in times when a key design strategy for e,cient vehicles is weight reduction. 2 Later, after I’d come to accept that hydrogen seemed to be the only clear option, I began being invited to give public lectures and to serve on task forces. On each occasion, I’d ask the audience (or fellow committee members): Can you think of anything other than hydrogen that could ful(ll this role? No realistic proposals came back. It was troubling. I disliked the idea of saying something was inevitable, hoped for an alternative that would allow me to be less absolute, less strident, less vulnerable to skewers. During these times, I also grew uneasy when people referred to hydrogen as an energy source—rather than something that allowed any source to power transportation (where is was most needed). My craving to clarify—to get things straight in my own head—led to the idea of “currencies”. It seemed we were missing the systemic role of hydrogen because we had no linguistic way to diLerentiate sources from (what I would come to call) currencies. “Running out” was the worry-of-the-day; (nding new sources to replace the old, the obsession. No one asked, “If we develop a new non-fossil energy source, how can we use it to Dy airplanes?” Moreover, the need for hydrogen reaches beyond transportation fuels. In setting out the second step in our rationale, a reality that could have been included, but wasn’t, is that fossil fuels also provide many of our material feedstocks—from building materials, to automobile, airplane and computer parts, to clothing and to supplement some foodstuLs. Moreover, even when the material itself contains nothing from the fossil source, fossil fuels are often still used to produce the materials. Steel, for example. Chemically, iron ore is Fe2 O3 . Today we use carbon to rip oxygen oL iron ore thereby leaving iron. A simple chemical-balance equation describes today’s process: 2Fe2 O3 + 3C → 4Fe + 3CO2 : This equation shows why CO2 is the principal (albeit invisible) eCuent from today’s steel making processes—thereby contributing to climate destabilization. But in the future we will be able to use hydrogen to do the ripping when the 2
The single advantage of ammonia over hydrogen is that ammonia can be more easily carried as a liquid. (It can also be directly used as a fertilizer.)
D.S. Scott / International Journal of Hydrogen Energy 29 (2004) 225 – 227
227
process equation becomes Fe2 O3 + 3H2 → 2Fe + 3H2 O: This time water is the eCuent and steel mills become better neighbors. Using hydrogen rather than carbon to manufacture materials—especially to reduce ores—involves more sophisticated ideas than simply using it as a fuel. So we’ll return to these ideas later. For now, let’s keep it simple. Let’s just remember: If we want to use the energy from windmills to Dy airplanes, then the windmills must manufacture hydrogen for H2 -fuelled airplanes. Nothing else makes sense. Climate-based rationale for H2 inevitability The maldistribution of global resources, the lower quality of hydrocarbon dregs, the risk of geopolitically triggered virtual depletion—and the price shocks that resulted—means depletion cannot be dismissed. Yet in an absolute sense, a diLerent, irrepressible force will overtake depletion as the reason to quit fossil fueling. That force will be the clear, immediate danger of catastrophic climate disruption. So let’s set out a second, (ve-step case for H2 age inevitability, this time based on climate disruption. 1. Atmospheric CO2 growth is bringing climate destabilization that, if unabated, will be catastrophic. 2. To eliminate anthropogenic CO2 emissions we require both non-carbon-emittingsources and non-carbon-carrying currencies. 3. There are many non-CO2 sources. 4. But realistically, electricity and hydrogen are the only two non-C currencies that together can supply the full menu of energy services. 5. Therefore, anthropogenic CO2 emissions can only be slowed by the extensive use of hydrogen and can only be stopped with the supremacy of sustainable-derived H2 among chemical fuels. Once again, by presenting this rationale in (ve steps we’re bequeathed a straightforward, easy-to-remember logic. And once again some points require further explanation. The (rst step in our rationale is simply the premise that climate destabilization, if unabated, will be catastrophic. The basis of this premise was introduced in earlier articles. But since it’s probably the greatest, yet most under-accepted risk facing 21st century civilization, we’ll return to climate destabilization in a later article in this series. The key point of the second step is also simple: We need more than non-carbon sources—we also require non-carbon currencies. Indeed, non-C currencies are even more important. I’ll explain why. If we use fossil fuels in stationary settings, it’s conceivable we could avoid the CO2 emissions if we could catch, then process and later sequester the carbon. 3 But how could we catch and sequester the CO2 eCuent from airplanes—or cars? Do we think aircraft could drag CO2 catching sacks behind them while these airplanes hurtle through the sky, (ve miles high, at speeds approaching that of sound—like the fen dou (manure-catching bags) I saw slung beneath horse’s tails as they clip-clopped through Beijing in the 1980s? The third step reminds us that we have many non-carbonaceous sources—from the windmills we’ve been talking about, to falling water, sunlight, nuclear power and so on. The fourth step of this logic names both electricity and hydrogen. From the beginning it has been clear that both currencies will be needed. Hydrogen alone cannot provide the full menu of services, just as today electricity can’t do everything. The hydrogen age won’t terminate electricity. Rather it will give electricity a wonderful new partner—a kindred spirit. It’s why I often speak, not of a coming hydrogen age, but of a coming hydrogen and electricity age. We’ll talk more of how hydrogen and electricity will work together in the next article of this series, “For Better or Worse.” Finally, we get to the (fth of this (ve-step case for inevitability. So obvious it’s anticlimactic. We’ve now come to a place from which we can see civilization’s inevitable future—at least the future of its energy system. And because the energy system underpins so much, it allows us to see much of everything else. Of course this inevitability assumes we achieve sustainability. If we don’t, civilization won’t have a future. Take your pick. This is the twenty-ninth in a series of articles by David Sanborn Scott Institute for Integrated Energy System, University of Victoria, Victoria, BC, Canada V8W 2Y2 E-mail address: [email protected] (D.S. Scott). 3 Today some fossil industries promote this approach. It can be entertaining to watch such entirely predictable pattern: threatened industries clawing at the past, rather than using their creative juices to exploit the future. At the best, carbon sequestering will be transitional technologies that might slow the inevitable decline of the fossil industry—but not by much. All such proposals fall into the category of “adding collectors” rather than “changing the process” that we discussed in the sixth article of this series, “From Oil Lamps to Lightbulbs”.