The Beginning of the End for Coal?

I saw in Tuesday's Washington Post that the EPA was ready to issue its proposed rules for CO2 emissions from new power plants. When finalized, these rules would apply to facilities larger than 25 MW that begin construction more than a year hence. As the Post notes, the chosen CO2 emissions limit of 1,000 lb. per gross Megawatt-hour (MWh) generated would make it virtually impossible for a new conventional coal-fired generating plant to comply with this requirement. That looks like another positive for natural gas, which is coal's nearest competitor today. It might also help baseload renewables such as geothermal, since wind and solar power don't ordinarily compete directly with coal. However, anyone reading this as the epitaph for coal in the US shouldn't be too hasty, because the EPA has left room for technology and other strategies to keep coal in the future mix.

I'm completely swamped with work and other commitments at the moment, so this posting will be more like an extended Tweet. However, I thought this news was too important not to comment on it, however briefly. Lacking the time to research these data myself, I'll rely on Ms. Eilperin's thoroughness and use her figures of 1,768 lb. CO2/MWh for the average US coal plant and 800-850 lb./MWh for gas. The latter is certainly a long way from state of the art, and I'm sure that a modern ultra supercritical coal plant would come in considerably below the 1,768 lb. mark, as well, yet still above the magic half ton. What intrigues me about the EPA's chosen performance standard is that meeting it would require much less than 100% capture and sequestration of a facility's CO2 emissions. Perhaps as little as 25-30% would be sufficient, particularly, if the plant were also designed to be co-fired with biomass, as some existing coal plants are. That combination, or some other similar strategy, could significantly reduce the cost of compliance and keep coal in the game.

I know that outcome wouldn't please those who see coal as not only the logical place to seek large-scale greenhouse emissions reductions, but also a major contributor to various local environmental impacts. Yet it's also an enormous domestic energy source, the global demand for which continues to grow. Moreover, as coal is increasingly displaced from power generation by cheap natural gas, its price is likely to drop, making it more competitive for export. So perhaps this isn't the beginning of the end for coal in the US, but just the start of a new phase.

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Because That's Where the Emissions Are

Yesterday the Environmental Protection Agency released its tabulation of greenhouse gases (GHGs) from large facilities in the US. In perusing the data I couldn't help thinking of the quote attributed to Willie Sutton concerning why he robbed banks. Even if he never actually said, "Because that's where the money is," the simple logic of that analysis transfers neatly to the question of why we might be interested in assessing and ultimately managing GHG emissions from such installations. While there are other important sources, notably including motor vehicles and aircraft, the more than 6,000 sites reported in the agency's online registry account for roughly half of all US GHG emissions. Furthermore, just a quarter of these sites--power plants--contribute nearly three-fourths of US emissions from large facilities. That's where the emissions are and where US climate policy should focus.

Although that doesn't dictate that we should entirely ignore all the other facilities, it certainly raises serious questions about the threshold of reporting for the hundreds of installations emitting less than 10,000 tons of CO2-equivalent gases per year, compared to the top-100 facilities, the smallest of which emitted nearly twice that much every day.

It should also challenge the belief systems of some members of Congress concerning the relative importance of different sectors. The highest-emitting oil refinery in the country is also one of the biggest in the world by throughput capacity, at 573,000 barrels per day. Yet it comes in at #45 on the list, with only one other refinery appearing in the top 100. The entire refining sector, comprising 145 plants, emitted around 5.7% of the total GHGs represented in the registry, and thus less than 3% of the US total. Why does that matter as more than an industry talking-point? Because reducing emissions from refineries by 10%--no easy task when they are already roughly 90% efficient in terms of their total energy output vs. inputs--would be lost in the rounding in our national emissions statistics. We won't get very far chasing expensive diminishing returns.

By comparison, reducing emissions from the 1,555 power plants on the list by an average of 10% would reduce US emissions by more than 3%. And because we are blessed with many more processes for generating electricity than for refining oil, this could be achieved in a variety of ways, nor does 10% represent any kind of ceiling for what might be possible. One option would be to retire the least-efficient coal-fired plants and take up the slack at existing gas-turbine power plants, plus some additional renewables. That may happen anyway, as a consequence of other EPA regulations. We could also replace the worst coal plants with near-zero-emission nuclear power plants of advanced design, such as the AP-1000 reactor that won NRC approval late last year, or the various modular nuclear reactors now under development. Capturing and sequestering the CO2 from coal-fired power plants would be another option, if it can be perfected at a reasonable cost.

I would never suggest that climate policy could be truly simple, but the numbers the EPA just reported, combined with what we know about the lifecycle emissions from the petroleum value chain, indicate that the scope of the US climate policy debate could usefully be narrowed to focus on just two main emissions sources: power plants and the end-use combustion of hydrocarbon fuels. On the scale of overall US emissions, almost everything else is noise. Of course that leaves plenty of room for discussion and disagreement on the most effective ways to address these emissions at the lowest cost and least disruption to an already-fragile economy. We can still argue endlessly about the relative merits of putting a price on emissions, providing incentives for emission-reducing technologies, and setting command-and-control regulations. Yet when we contrast the potential effectiveness of such a limited approach with the intricacy and distortions entailed in "comprehensive" efforts like the failed Waxman-Markey climate bill of 2009, it looks like a very helpful simplification to pursue.

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Are Oil and Gas Renewable?

A long-time reader of this blog sent me a link to a New York Times article highlighting the diverse scientific pursuits of Jesse Ausubel of Rockefeller University, among which is the exploration of the "deep carbon cycle". Although much is known about the behavior of carbon in the first seven miles or so of the earth's crust into which we routinely mine and drill for resources, relatively little is known about the flows of carbon-based compounds in the other 99.6% of earth's total volume. Increasing our knowledge in this area could have momentous implications for our long-term energy supplies, while expanding our understanding of the processes affecting climate change. It's also just plain fascinating.

Mr. Ausubel was already well-known in energy circles for his assessment of the progressive decarbonization of our energy consumption since the start of the industrial revolution and continuing into the future. Some colleagues at Texaco introduced me to his work on that subject in the mid-1990s. However, until I read the Times article I was unaware of his involvement with the Deep Carbon Observatory, an international project of the Carnegie Institution to investigate the organic and inorganic carbon cycles deep in the earth. Although this involves such esoteric questions as the disposition of the carbon content of the "planetesimals" that accreted to form the earth billions of years ago, it also has much more practical aspects, such as the origins of oil and gas. That includes both the fuels we consume and the methane and other hydrocarbons released into the environment without human intervention.

Most experts in the oil and gas industry accept the traditional Western view of these substances as fossil fuels, the remains of ancient forests and dinosaurs that have been processed into their present form by exposure to high pressures and temperatures over the course of millions of years. Although most hydrocarbons weren't formed in the reservoirs where they are found today, it's generally assumed that they were generated from organic material in sedimentary rock elsewhere and migrated until they reached the various geological structures that trapped and stored them for subsequent discovery and exploitation. The shale gas that has been the subject of so much activity and debate in the last few years is a special case, for which the source and trap are one in the same: organic-rich rock with such low porosity that the gas can't escape without assistance.

However, there's another, more controversial theory of the origins of at least some oil and gas, suggesting that they were formed by chemical or biological activity much deeper in the earth, and then migrated long distances before being trapped. If correct, that would mean that not only aren't these fuels truly fossils--and thus essentially static and finite--but that they might actually be continuously regenerated by natural processes in much shorter time spans. A number of academics appear to hold this view, and it was a common theory of petroleum origin among Soviet scientists. Much of this is explored in a lengthy white paper on the Deep Carbon Observatory site, including the shortcomings of current analytical techniques in determining definitively whether a given sample of methane originated from organic material in sedimentary rock or from some other source.

Finding gas or oil in deposits much deeper than those we already know about, or in places that aren't consistent with our present understanding of petroleum geology, would represent an even bigger potential energy revolution than the one begun by the recent development of the means of unlocking shale gas resources. It would also shift our perspective on the nature and required speed of the energy transition on which we've embarked. If oil and gas weren't finite--at least in human terms--it might alter the urgency of deploying some of the alternative energy technologies now in our repertoire. At the same time, it would have enormous implications for climate change, by greatly increasing the ultimate quantity of carbon we could eventually emit to the atmosphere.

From my reading of the material on the Deep Carbon Observatory site, it would be extraordinarily premature either to celebrate or panic--depending on one's perspective--over this prospect. The possibility of extracting useful quantities of hydrocarbons from unknown reservoirs in the deep earth remains speculative and might never come to pass. As a presenter from Shell put it in a slide deck from a conference on the subject, "Shell is not interested in drilling exploration wells into Earth's mantle in search of petroleum fluids." But despite understandable skepticism about the underlying theory of deep carbon and the failure of previous efforts to prove it, I don't see how it can be disproved without a much more detailed picture of the earth's interior than we are likely to possess for a long time.

The likelier near-term outcomes of the work of the DCO's multi-disciplinary researchers from industry, government and academia are both more benign and far less polarizing than the cornucopia of hydrocarbons it might someday uncover. Better techniques and instruments for analyzing the carbon and hydrogen isotopes in methane and other hydrocarbons could have wider application in many fields, including pharmaceuticals, while a better understanding of the physics and chemistry of the deep carbon cycle could lead to lower-cost and more widely acceptable means of sequestering the CO2 emissions from our use of "fossil fuels", regardless of their origin. I look forward to hearing about the progress of these efforts.

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Carbon-Neutral Gasoline

I see that Google's venture capital fund is investing in a startup company that would produce hydrocarbon fuels from cellulosic plant matter, with the added twist of sequestering carbon in soil. This is another signpost of the growing interest in non-alcohol biofuels, often referred to as "drop-in" fuels, for both oil replacement and climate mitigation. With cellulosic ethanol developers having mainly disappointed for the last several years, and with so much current policy focus on electric vehicles and their infrastructure, I find it reassuring that there are smart people out there working on alternative fuels that fit today's cars, with today's infrastructure. That's important not just for the obvious reasons, but because the end result of energy policy must create successful business models, not just neat technology.

I haven't delved deeply enough into the technology of CoolPlanetBioFuels to form an opinion about its potential, though I do have some questions about how their front-end "thermal/mechanical processor", which will apparently be produced in 1-million gallon-per-year modules, would mesh with the catalytic fuel production processes needed to turn its output into consumer-ready fuels. Those processes normally operate at scales 100 times larger than CoolPlanet's processor, and when it comes to the efficiency of industrial chemistry, smaller is rarely better. However, if their technology works as advertised, the company's pursuit of the mainstream fuel market looks like a smart business decision.

A few years ago, the main buzz in alternative fuels concerned the production of ethanol from cellulose, and companies large and small were pouring money and resources into different ways to do this, as were governments. That's still happening, despite many of the companies involved missing their early production targets so badly that the Environmental Protection Agency twice had to revise its annual Renewable Fuel Standard (RFS) mandate to compensate for the shortfalls. However, the bigger worry about cellulosic ethanol might not be its production, though that is quite challenging enough, but its ultimate market. That's because corn ethanol has effectively filled up the easiest outlet, consisting of the 10% of a gallon of ordinary gasoline that ethanol can occupy without potentially compromising the fuel systems of cars not designed as flexible fuel vehicles, as well as refueling infrastructure that appears not to be up to handling more ethanol. The EPA has approved a 15% blend, but it faces both litigation and significant practical constraints.

Then there's E85, the 85% ethanol/15% gasoline blend that was expected to provide all the market headroom that ethanol producers would need, when the RFS goals were enacted in 2007. Yet despite generous tax incentives for E85 station conversions and a price that currently averages 53¢ per gallon less than regular unleaded gasoline on a volumetric basis--though still about 50¢/gal. more on an equivalent energy basis-- E85 remains something of a dud, even in the heart of corn country. E85 sales set a record last year in Iowa, but the 9 million gallons sold through 138 outlets there accounted for just 0.7% of the gasoline sold in the state in 2010.

If you want to make money selling motor fuel--or as in the case of CoolPlanet making the hardware for making fuels--then you must come to grips with the commodity nature of its markets. After water, motor fuels are probably the world's largest commodity business. That means that volume, rather than high margins, is the main driver of revenue and profits. The major oil companies struggled with this for decades, pursuing the last penny a gallon of margin by means of additives and advertising. Many of them have left this segment entirely to franchisees, because it's typically not profitable enough to compete with their other investment opportunities. Niche markets can be attractive if they offer unusually high margins, such as those available in the 200 million gallon-per-year aviation gasoline business, which supports just a few players. However, it's not obvious that ethanol and E85 fall into that category. So if you want to develop your business based on its growth potential, and your technology gives you a choice between selling into an at least temporarily saturated ethanol market or the much larger market for fuels that don't require special infrastructure or dedicated fleets, opting for the latter looks like a no-brainer.

The extra angle CoolPlanet offers comes in the form of its sold carbon byproduct called "biochar". This is sometimes referred to as "terra preta", which was a pre-Columbian charcoal-based fertilizer used in South America. The idea is that by returning this product to the soil, rather than allowing the carbon of the biomass to decay into CO2 and enter the atmosphere, the entire process can be made carbon neutral or even carbon negative, sequestering as much or more carbon as the liquid fuels produced will emit when burned. Terra preta is something of a hot topic lately, though the logic of burying solid carbon in one location at the same time that others are mining solid carbon--a.k.a. coal--from the earth elsewhere somewhat escapes me. Nor would the gasoline produced from CoolPlanet's process be any more carbon neutral in effect than conventional gasoline produced by a company that scrupulously bought matching emissions offsets for its products, which could currently be had for a cost of around 9¢ per gal. via an organization like CarbonFund.org.

It's hard to assess the value of the climate-friendly aspects of CoolPlanet's technology in the US, given the uncertainties about pending EPA greenhouse gas regulations and Congressional legislation. However, the attractiveness of a renewable energy technology that unlike wind, solar and geothermal power could actually displace oil on a barrel-for-barrel basis, and that isn't subject to ethanol's limitations and drawbacks, is understandable. All that remains is for CoolPlanet to demonstrate that their device really works and that they can bring it to market at a price that allows the fuels it would produce to compete with commodity fuels from petroleum. That would be big news, indeed.

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FutureGen Switches Tracks

The standard knock on carbon capture and sequestration (CCS) is that it hasn't been tested and proven on an industrial scale. That's really only true in the narrow sense in which you start with coal, produce electricity, and then collect and bury the CO2 that comes out the stack--which I imagine is what CCS evokes for most people who have even heard of the technology. Some years back, the US government set out to close that gap by building a large-scale test facility to demonstrate the coal-to-CCS cycle, with help from a consortium of industry partners. The program was called FutureGen. It died in 2008 after reported cost overruns but was revived in a different format last year. Now the reoriented effort has spawned a new project at a different location--though still in Illinois--to replace the ill-fated Mattoon project. Its basic concept differs significantly from the original FutureGen, and in ways that might improve the odds that coal could continue to contribute a substantial share of the US energy mix for many decades.

The CO2 produced by power plants is much harder to capture and dispose of than the traditional pollutants we associate with them, not least because it is the primary chemical result of the combustion of hydrocarbons, along with water vapor, rather than a byproduct resulting from a fuel impurity or imperfect combustion. That requires dealing with emissions that exceed the mass of fuel being consumed, rather than an order of magnitude or two smaller. And when fossil fuels are burned in air, the CO2 produced must be separated from all that nitrogen, which is the largest constituent of flue gas, before it can be sequestered. All this is expensive, in both energy and financial terms. The original FutureGen was designed to finesse this problem by converting coal into a hydrogen-rich gas that could be burned efficiently in a combined-cycle gas turbine (IGCC), producing emissions consisting mainly of water vapor, plus a sequestration-ready CO2 stream from the hydrogen-production process. Unfortunately, the hardware necessary to do that isn't cheap, either.

FutureGen 2.0, as announced, would take a different tack. It aims to convert an existing power plant owned by Ameren Corporation into an "oxy-coal" plant, in which pure oxygen replaces air in the boiler for combustion, resulting in flue gas consisting mainly of CO2. This approach has pluses and minuses, compared to IGCC. It requires a bigger air separation plant to support full combustion, but it eliminates all the hardware associated with hydrogen. That should entail somewhat lower capital costs, but not necessarily lower operating costs, particularly when you consider that the efficiency of IGCC exceeds that of most existing US coal power plants, though not necessarily supercritical or ultra-supercritical pulverized coal plants. (I couldn't tell how much the basic power block of Unit 4 of Ameren's Meredosia, IL plant, which formerly burned fuel oil, will be modified.) As in FutureGen 1.0, the resulting compressed CO2 would then be pipelined to a disposal site elsewhere in the state.

Although it would take some doing to convince me that oxy-coal with CCS is a better technology than IGCC with CCS, the revised approach to FutureGen looks like a good call on the part of the government. That's because the context in which FutureGen is being pursued has altered significantly since it was first devised. Instead of a scenario of continuing to build many new coal-fired power plants every year to meet steadily-growing electricity demand, the future--at least in the US--looks quite different. An article in yesterday's Washington Post pointed out that a number of new coal plants are still under development, but the rate of new construction has slowed dramatically, due to regulatory pressures, weaker electricity demand, competition from cheaper natural gas, and the growth of renewables. If we want to have an impact on the emissions from the US coal-fired power plant fleet--which accounts for 31% of total US emissions and 91% of the emissions from the electricity sector--then our best strategy probably doesn't involve building hundreds of gleaming new IGCC plants, but rather retrofitting hundreds of existing units built with older technology, for which conversion to IGCC would likely be cost-prohibitive. If FutureGen 2.0 succeeds--technically, if not economically--it would validate that retro-fitting potential.

The world hasn't stood still while the Department of Energy wrestled with all the political and technical challenges that FutureGen faced. The original siting competition between Texas and Illinois looked like a textbook case of logrolling, and FutureGen 1.0 exhibited the hallmarks of a classic government boondoggle. Meanwhile, commercial projects such as Duke Energy's Edwardsport IGCC (without CCS, but in effect CCS-ready) and the Good Spring IGCC project of Future Fuels LLC have emerged and appear to be making progress. The latter is based on technology from the Thermal Power Research Institute of China, which is a good bet to beat all of these projects to the punch with its GreenGen power plant in Tianjin. If FutureGen 2.0 is going to matter, it must be built smartly, quickly and cost-effectively. Yet technical success still won't guarantee that this technology will be taken up and deployed widely. In a market economy, rather than a centrally-planned one, it's hard to see any of this going beyond a demonstration plant or two without a substantial price on CO2 emissions to offset the inherently higher costs of generating power this way.

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Rejecting Reactive Energy Policy

I see that BP now thinks it might be able to cap its leaking Macondo well this month, rather than sometime in August, barring a major hurricane or other disruption. That can't come a moment too soon, and not just for the obvious reasons. Every day that the well continues to spew oil into the Gulf of Mexico contributes to the mounting appearance of panic among policy makers, who have allowed--willingly or otherwise--the oil leak to hijack our progress towards a sensible energy policy that addresses both energy security and greenhouse gas emissions, based on a rational assessment of the tools available now and the timing of future options. The sooner the oil spill is off the front page, the sooner work can resume on that effort.

One of my old commodity-trading mentors liked to remind his more junior colleagues to "sell the news and buy the facts." By this he meant that those who get carried away by the emotion of current events are liable to be whipsawed when reason returns with a little time and perspective. More than a few members of Congress and the administration could benefit from that insight right now, as the understandable reaction to the oil spill whips up exaggerated rhetoric concerning our addiction to oil and the prospect of ending it sometime soon. Funny that we don't hear much about Europe's addiction to oil, which at least in terms of its relative reliance on oil imports looks even more serious than ours, despite astronomical motor fuel taxes and an emphasis on biodiesel that nearly matches our focus on ethanol. Since Europeans have consistently focused on this problem for years, perhaps it's just not as easy to solve as some Representatives and pundits imagine. If that's true, does it make sense to divert our focus away from a comprehensive approach to both emissions and broadly-defined energy security, in order to zero in on the most daunting element of both concerns?

First consider the oil-security portion of the problem, which in many ways was clearer in 2008, when oil prices zoomed past $100/bbl and headed for $150, until both they and the economy broke later that year. Americans got the message that conservation and efficiency were the top priorities for dealing with the cost of our oil addiction. The oil spill doesn't alter that. Although prices have come down considerably since mid-2008, they remain well above the pre-2004 level of $20-30/bbl or so, when gasoline was consistently under $1.75/gallon. As a result of those pressures, motorists cut back on their driving, and the Congress enacted--and this administration implemented--the most significant increase in Corporate Average Fuel Economy requirements in a generation, taking the new-car average CAFE standard to 34 mpg by 2016, including both passenger cars and light trucks/SUVs. Based on forecasts by the Energy Information Agency of the DOE, these rules, along with prudent conservation, should reduce US gasoline consumption by 2.6 million barrels per day by 2030, compared to pre-CAFE forecasts. And although I've disagreed with some of the specifics of these regulations, particularly for failing to correct outdated assumptions and allowing carmakers to double-count the benefit of electric vehicles, these new standards will eventually transform the US vehicle fleet and the energy it consumes.

We also shouldn't allow our revulsion at the oil spill to blind us to the emissions implications of our energy choices. In 2008 oil accounted for over 37% of US primary energy consumption and 35% of our greenhouse gas emissions, while coal contributed 22.5% of primary energy but 30.5% of emissions, including a whopping 91% of the CO2 emissions from the electric power sector. That distinction is crucial, because while we still have limited and only partially-effective substitutes for oil in transportation, where most of it is used, we possess a wide array of options for reducing the emissions from electricity generation, which consumed just 1.3% of total US oil demand last year. Several of these are economically viable today, though most require some level of subsidies or incentives. Nuclear power and geothermal energy are effective low-emission alternatives for baseload generation, while natural gas and renewables are already making significant inroads into coal's market share of overall power demand. And if implemented on a large-scale, integrated basis, carbon capture and sequestration could enable coal to continue to compete in a low-carbon electricity marketplace.

None of this suggests a return to the pre-spill status quo. The impact of the spill on the oil industry and the regulations that govern it will be significant and long-lasting, as it should be. At the same time, it would be hard to assess all of the public evidence assembled so far and not conclude that the accident that destroyed the Deepwater Horizon rig and led to the uncontrolled leak of many thousands of barrels per day of oil into the Gulf was entirely preventable--not by a ban on drilling in deep water, but by prudent adherence to sound operating principles and practices and the consistent enforcement of regulations to ensure that adherence by even the least-cautious operators. Yet as necessary as creating a universal culture of safety and caution in offshore drilling is, we can't let this urgent task divert our attention from the important long-term drivers of US energy policy and the actions--many already underway--necessary to address them. Good energy policy can handle all of this, while overly-reactive policies focused on the Macondo spill and the political opportunity it presents risk misallocating our priorities and creating a legacy that would make our long-term energy situation even more challenging than it already is.

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A Framework for Geoengineering

This week's Economist includes coverage of a recent meeting of scientists at Asilomar, in California, to discuss the ground rules for pursuing "geoengineering", the deliberate, large-scale modification of the earth's environment. The purpose of the geoengineering now under consideration is to limit or reverse the effects of climate change, presumably whether man-made or otherwise. This is a notion that provokes great anxiety or outright revulsion on the part of many who feel our only acceptable response to global warming is to return the planet to something approximating its pre-industrial state by eliminating the emissions and land-use changes that have accumulated over the last century or more. However, for those of us who doubt either the efficacy or achievability of such drastic changes in the economy and our lifestyles, geoengineering is at least a legitimate, complementary option along with mitigation, and potentially our last hope of averting a worst-case climate scenario, should one arise.

Anyone who is convinced of the dangers of global warming or climate change, whichever you prefer, implicitly accepts the potential of geoengineering, because anthropogenic climate change (AGW) ultimately amounts to an uncontrolled experiment in geoengineering on a global scale. The kinds of experiments proposed by researchers meeting at Asilomar--the site of other notable, long-view discussions in the past--would operate on a much smaller scale, at least initially, with the goal of either undoing or holding temporarily in abeyance the changes resulting from humanity's emissions of heat-trapping gases in excess of the capacity of the earth's massive natural GHG-recycling facilities to absorb. For that matter, geoengineering might even be useful if it turned out that AGW was only one of several factors combining to shift conditions away from the benevolent state that has supported humanity's rise as the dominant species on the planet.

This is an issue that I've been following for a long time, though I haven't written about it very often here. My interest in geoengineering was piqued in the 1990s by proposals to sequester large quantities of CO2 in the oceans by stimulating plankton growth where there naturally wasn't much. That's only one of many possible approaches that fall into a broad family of carbon-removal strategies constituting one of the two main geoengineering categories The Economist considered. "Solar Radiation Management", the other category, includes strategies for reducing the amount of solar energy the earth receives or retains. That could run to putting large numbers of small particles in the upper atmosphere or orbiting giant mirrors to deflect sunlight off into space. It might even be as simple as painting all rooftops white--a bit of a problem if they're all covered with dark solar panels.

The basic problem seems to be convincing everyone potentially affected--which of course might include everyone on earth, or at least their representatives--to trust researchers to keep the impact of their experiments strictly limited and under tight control. The session at Asilomar apparently endorsed a set of steps called the "Oxford Principles", which describe five key elements for gaining concurrence:

1. Geoengineering to be regulated as a public good.

2. Public participation in geoengineering decision-making.

3. Disclosure of geoengineering research and open publication of results.

4. Independent assessment of impacts.

5. Governance before deployment.

Now, these sound pretty good as a set of basic principles, particularly if your goal as a researcher, or as the institution or nation funding the research, is to get everyone onboard before you start. Among other things that might avoid having someone turn up later to accuse you of making things worse, at least locally. Geoengineering liability is a serious concern at the individual and institutional level, and it could extend to being considered an act of war at the national level, if things turned out really badly. Unfortunately, when I consider how these principles might actually work--including stifling the involvement of for-profit companies in either the funding or actual R&D role--I believe they describe a likely path to doing nothing. Imagine having tried to get the delegates at Copenhagen to agree to let someone put finely-divided salt particles into the atmosphere over, say, the Arctic, to make clouds more reflective. Might as well have tried to sell them the Brooklyn Bridge at the same time.

That's the core of the problem as I see it: If we do end up needing to deploy geoengineering, it's likely to be precisely because we were unable to get every country on earth--or even just the small subset of large emitters--on the same page with regard to climate change, let alone establish a universally-trusted body to oversee their mitigation efforts. If we yoke geoengineering to the same UNFCCC/IPCC process that brought us the Copenhagen Climate Conference and the Kyoto Protocol, then we might as well forget it and try to figure out where to invest in the likely new beachfront property of the 2050s. In any case, as appealing as the Oxford Principles might seem from a stakeholder-engagement perspective for implementing large-scale geoengineering someday in the future, they look too unwieldy to guide the small-scale R&D efforts that would be needed to determine which, if any, of these schemes actually have merit.

One possible alternative would start with the same concept of climate forcing that underpins today's climate models. (And by the way, any serious geoengineering effort is going to require really good, trustworthy global and regional climate models, the inherent limitations of which are one of the main complaints of climate skeptics.) The observed increases in CO2 and other greenhouse gases equate to roughly an extra 2 watts per square meter of heat radiation retained by the earth, out of a total average influx of around 240 w/m2 at the earth's surface. So if 1% more radiation/retention is enough to cause the global warming we have observed, then what is the maximum equivalent level of geoengineering testing we'd be willing to tolerate to see whether any of these techniques might help? 0.01%, or 1/100th of the scale of the problem itself? And what would be the most any one experiment should be allowed to fiddle with? 0.0001%, or one part per million, allowing at least 100 small experiments under the overall limit? (For experiments dealing with carbon-removal, rather than radiation management, this forcing threshold could easily be converted to its tons-per-year of CO2 equivalent.) Whatever the level, the idea would be to keep any individual experiment, and all of them together, below the level at which they could make things noticeably worse by accident--with a healthy margin for error--without preventing any work from being done on this at all.

Some regard geoengineering as yet another outgrowth of our technological hubris and thus unworthy of further research. While I respect anyone's right to that view, I would also question their commitment to the survival of the human race. That's because I'm deeply skeptical that our current approach to climate change can work fast enough and on the necessary scale to avert the worst outcomes scientists suggest we face. We already live in a geoengineered world that couldn't support a fraction of its current population if we returned it all to its natural, pre-industrial state. That's not a license for unlimited tinkering with our environment, and perhaps that's the underlying concern: that the same techniques that might be applied to reduce the impact of climate change might eventually be employed in risky attempts to fine-tune an even more optimal climate than the one we inherited. Science is like that, as demonstrated by nuclear proliferation and questionable medical practices. But while I share those misgivings with respect to the potential misuse of geoengineering, I sure want us to have some of these options in our hip pocket if we ever really need them.

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To Bury CO2 or Recycle It

While not the most powerful of the greenhouse gases produced by humanity, CO2 is certainly the most prevalent, if you don't count water vapor. To a very large extent, addressing climate change depends on three main strategies for dealing with the excess CO2 our activities emit: avoiding its creation by switching to other energy sources, such as renewables or nuclear power; capturing and storing it in trees, other vegetation or underground; and recycling it into useful fuels and products. Most of the work to date on the third option has focused on biofuels, which employ photosynthesis to convert CO2 into vegetable oils or fermentable sugars. However, another strategy now attracting interest involves non-photosynthetic pathways for turning CO2 back into hydrocarbons. If practical, this approach has much to recommend it, though the laws of Thermodynamics suggest it will always require more energy than the resulting fuels can deliver when used. A recent conversation with the CEO and CTO of Carbon Sciences, Inc., a start-up pursuing CO2-to-fuel technology, shed some interesting light on the subject.

The magnitude of global emissions of CO2 makes managing them a daunting prospect. Carbon Capture and Sequestration (CCS), which creates an artificial carbon cycle, has garnered much political and financial support in the last year, though it is still in the development stage and faces significant hurdles. CO2-to-fuel conversion offers another interesting option, because it could either work in parallel to CCS to enhance the reduction of emissions from fossil-fuel power plants and other stationary sources, or in competition with sequestration as an outlet for the captured CO2 from such facilities. If the resulting synthetic fuel displaced a like quantity of petroleum, natural gas or coal, the effect on the atmosphere would be largely equivalent to CCS and likely better than conventional biofuels, which appear to result in substantial non-combustion releases of CO2 and other GHGs. Fuels produced from recycled CO2 could finesse many of the NUMBY concerns about CCS while beating corn ethanol and some biodiesel on overall "green-ness" and compatibility with existing fuel infrastructure and transportation fleets. So why aren't we already doing this?

The answer is simple. When we burn the carbon compounds found in fossil fuels, they produce CO2 and a specific quantity of energy that is unique for each molecule. Turning CO2 back into the original fuel compound requires the input of that same amount of energy--that's from the First Law of Thermodynamics--and in practice a bit more, thanks to the Second Law. Chemists have known for a long time that CO2 could be converted into fuel and chemicals, but outside the laboratory this wasn't regarded as useful, because it inherently consumed more energy than it could return. Biofuels get caught up in this same conundrum, though in their case much of the energy required is supplied by the sun, rather than from other fuels and energy inputs we must produce. So I was quite intrigued when I received an email inviting a conversation with the CEO of Carbon Sciences, the start-up I mentioned earlier, which claims to have solved this problem using "biocatalysts", nanotechnology, and a unique multi-step process.

The company's website includes animation showing how this would work, though from my perspective it omits the key factor: where does the energy come from to drive the process? Catalysts and enzymes can reduce the threshold for the reaction to take place and improve its speed--the reaction kinetics, in engineering terms--so that what would otherwise take nature years or millennia to produce can be accomplished in a commercially-practical interval. However, catalysts can't alter the basic energy requirement of the reaction. What is the source of that energy?

My discussion with Carbon Sciences' CEO Byron Elton and Chief Technology Officer Naveed Aslam, Ph.D. assuaged my immediate concern that this was yet another perpetual motion machine dressed up with technical jargon and fancy graphics. They struck me as pragmatic and realistic about the challenges they face, though with the customary optimism required for entrepreneurial risk-taking. Dr. Aslam clarified that their process for converting CO2 to methanol for later conversion into hydrocarbons or petrochemicals involves a hydrogen-and-energy carrier molecule that must be regenerated from a "sacrificial substrate." That substrate effectively provides the energy required for uplifting the CO2, which is at a very low energy state, and acts as the fuel source for the whole sequence. The value of the entire CO2-to-fuel process in energy, economic and emissions terms thus hinges on the characteristics, cost and supply potential of this energy-donating material.

The process developed by Carbon Sciences can apparently use a variety of substances for this purpose, which is fortunate. Initial laboratory tests apparently involved glucose, a commercially-available sugar, but the company is now using another, undisclosed feedstock because of their concerns that glucose supplies couldn't keep up with a large-scale CO2-to-fuel industry without affecting food prices. Dr. Aslam indicated that in the long run they would likely use a mineral-based compound that was widely available. Without knowing the specific chemical involved, it's impossible to assess the overall energy balance, lifecycle emissions, or usefulness of the process, but I at least came away with a sense that Mr. Elton and Dr. Aslam understand the constraints involved very well.

And while the global supply of CO2 certainly looks large enough, it has to be provided in the right form: highly concentrated and free of contaminants that could degrade their catalyst or retard the reaction rate. That is a very different requirement from biofuels that extract their CO2 from the air, and it would put CO2-to-fuel in direct competition with carbon sequestration and enhanced oil recovery, which also effectively produces incremental fuel from CO2. It's not obvious to me which technology will advance the fastest, offer the largest overall CO2 reduction, or the most attractive economics. Markets are usually the best way to sort that out, if given the right signals.

Nor are Carbon Sciences the only ones working on this problem. A team at Sandia Laboratory has been developing a "Sunshine to Petrol" system using CO2 and concentrated sunlight, while the new Advanced Research Projects Agency-Energy (ARPA-e) is looking into a variety of novel ways to convert CO2 into fuel without photosynthesis.

It's important to note that Carbon Sciences' conversion technology is still at an early phase of development--lab-scale, rather than demonstration-scale. "Milliliters per day" won't solve our energy or emissions problems, but if this can be scaled up to many thousands of barrels per day with a cheap and readily-available source of chemical energy and a suitable supply of CO2, it has the potential to deliver fuels that are 100% compatible with our current infrastructure and vehicle fleets. That's a big advantage, and it would certainly explain the interest that Carbon Sciences has apparently been getting from large energy firms. I was told that Carbon Sciences hopes to develop a commercially-attractive package by the third quarter of 2010 and are exploring a "strategic partnership" to take the process--and the company--to the next phase. They have also applied for DOE technology funding under the category of "Innovative Concepts for Beneficial Uses of CO2". I will be watching their progress with great interest.

Since I don't expect to post again until next week, I'd like to wish my readers a Merry Christmas and happy Boxing Day.

I also have a housekeeping matter to bring to your attention. Haloscan, the comment system I have used since 2004, is being discontinued. I must decide by Monday whether to switch to Haloscan's successor, Echo, use Blogger's comment feature, or find another comment platform. Although I will do my best to ensure the migration of the many thousands of comments you've left here, I can't guarantee it. If there are any you'd like to refer to again, I encourage you to copy them to another medium.

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Sequestration and Education

Yesterday afternoon I began scrutinizing the Senate climate bill, S.1733, widely referred to as the Kerry-Boxer bill. Like the Waxman-Markey bill that the House passed in June, the scope of Kerry-Boxer goes far beyond the establishment of an economy-wide cap & trade system for reducing greenhouse gas emissions, though at a comparatively skimpy 821 pages it has yet to acquire as much baggage as its counterpart accreted on its way to a floor vote. I was struck by the emphasis both bills place on carbon capture and sequestration (CCS), not just as a technology that receives significant support, but as the only viable pathway offered for new coal-fired power generation. However, as I looked through the provisions relating to permitting of sequestration sites and the innocuous-sounding section 812, "Performance Standards for New Coal-Fired Power Plants", I spotted a significant omission. There's nothing here to address what might constitute the largest non-technical barrier to implementing CCS. Public acceptance of it entails a significant educational effort on the efficacy and safety of this new technology. That will require going beyond the details of CCS to provide Americans a primer on basic geology.

The stakes are high. Despite recently losing some market share to natural gas and renewables, coal-fired power plants make up the single largest source of electricity in the US by a wide margin. In the 12 months through July, coal accounted for 46% of US power generation, compared with just 3% for non-hydro renewable energy. Short of simply shutting down every coal-fired power plant and leaving a gaping hole in our national electricity supply that the current generation of renewables can't yet fill, we need to find a way to control the emissions from coal directly. That's where CCS comes in. The coal power performance standards in Waxman-Markey and Kerry-Boxer would require that by no later than 2027 any new coal-fired power plants licensed after 1/1/09 must cut their net CO2 emissions by at least half. CCS looks like the only practical way of doing that--if you can call something that has been deployed so sparingly practical. But how can CCS be implemented if the public isn't willing to have CO2 stored underground anywhere?

CCS is new, but it's not so new that it hasn't already attracted pushback. Earlier this year Shell encountered significant opposition to injecting CO2 into a depleted gas field in the Netherlands. Meanwhile Vatenfall's project at Schwarze Pumpe in Germany is apparently venting its captured CO2 to the atmosphere, because the firm can't get a permit to inject it. "Not in My Ground", is how another article described opposition to carbon sequestration at an Ohio ethanol plant. My Google search even turned up a blog entitled, "Citizens Against CO2 Sequestration." Aside from the technical challenges associated with separating, transporting and injecting CO2 into geological storage sites, do these opponents have a scientific basis for being concerned about the health and safety risks? Perhaps, though an article on the subject cited by the Citizens Against blog that refers to the health hazards of drinking water mixed with CO2 had me rolling my eyes. Perhaps the author was unaware that hundreds of millions of us do that every day; we call it soda pop, and it's a big business.

Rather than dismissing all this as a simple case of uninformed NIMBYism (or as the Guardian newspaper in the UK referred to it, "numbyism", as in not under my back yard) I suspect it reflects a fundamental gap in the public's understanding of what lies beneath its feet. I simply cannot count the number of people I've encountered in the course of my long career in energy who were under the impression that oil was found as pools in giant underground caverns, rather than contained within tiny pores in solid rock strata. If most people so badly misunderstand the geological basis of a technology as established and commonplace as oil & gas drilling, how on earth can we expect them to have a coherent picture of what happens to CO2 when we pump it underground? Of course they're going to fear it could all come right back out and possibly asphyxiate them, in the manner of the volcanic CO2 seepage at Lake Nyos in Cameroon and elsewhere.

From my own perspective, the existence of enormous natural gas reservoirs--confusing terminology, perhaps--constitutes a sufficient proof of concept by demonstrating that gases can be stored safely underground for intervals as long as millions of years. If impermeable cap rock can seal in billions or trillions of cubic feet of methane, the molecular diameter of which is smaller than that of CO2, then once the CO2 is down there, the vast majority of it is going to stay there. But just as telling people that a flu vaccine is safe apparently leaves large numbers of them unconvinced, I conclude we need to invest a fair amount of time, attention and resources into educating the public about the science and safety of injecting CO2 under the ground, before we can base our national energy strategy on this technique.

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Sequester Oil Instead of CO2?

I've been following developments in carbon capture and sequestration (CCS) for more than a decade, so I was intrigued to run across a novel suggestion for an entirely different approach, involving the "sequestration" of undeveloped oil instead of the CO2 emitted by power plants and other industrial facilities. Even allowing for the likelihood that this trial balloon by Ecuador is either intended to enhance its government's leverage in negotiations with potential oil developers, or constitutes an outright scam--the resources in question apparently lie beneath a designated national park--the idea of selling emissions offsets based on the carbon content of forgone oil output is just plausible enough to merit a bit of analysis.

The basic idea seems clever. If it's so hard to capture the CO2 from burning fossil fuels and prevent it from accumulating in the atmosphere, why not leave the carbon in the ground and take credit for that by selling emissions offsets? The benefit of such a transaction, in both environmental and economic terms, would hinge on two key parameters: the carbon content of the specific grade of oil involved and the extent of the reservoir holding it. In other words, how many barrels would be spared, and how many tons of CO2 would be avoided for each barrel? Neither figure could be determined with certainty without some actual drilling, but non-invasive seismic techniques might supply an estimate of the approximate size of the potential reserves involved, while the quality might be guessed by analogy to actual producing fields elsewhere in the country. With these estimates in hand, we could arrive at an approximate value for the avoided emissions.

Lacking detailed information on these Ecuadoran oil reserves, I'm going to punt on quantity and focus on quality and its implications for the unit price of the resulting emissions offsets. If there's enough oil there to be of commercial interest, then that ought to be a sufficient starting point to assess the merits of leaving it in the ground as a means of combating climate change. As a first approximation on quality, let's assume the oil is similar to the Oriente crude that makes up most of Ecuador's output. Oriente is a medium-sulfur, medium-gravity crude similar to the oil produced on the Alaskan North Slope and run in many US West Coast refineries. Its API gravity is listed at 29.2, corresponding to a density of approximately 308 lb. per barrel. Applying a little basic chemistry suggests that each bbl burned would emit roughly 1004 lb. of CO2, so if we knew what the oil was worth, we could easily derive a cost per ton of CO2.

Because the oil in question is still under the ground, its price can't be looked up on an exchange. However, companies are bought and sold on the basis of reserves that have yet to be produced. A recent report from IHS Herold and Harrison Lovegrove & Co., Ltd. indicated that the average value of such M&A transactions in 2008 implied a value of $11.51/bbl for proved reserves and $5.25 for "proved plus probable." The latter figure seems more relevant to the current situation, since the reserves in question couldn't be fully proved without precisely the kind of development work this idea is designed to avoid. Applying the lower "2P" figure to the CO2 calculation above results in an equivalent value of about $11 per metric ton of CO2 offset. That's roughly the same as the estimate for the proceeds from cap & trade implicit in the federal budget the Obama administration submitted to Congress and lower than the price at which offsets are trading on the European Climate Exchange.

The basic flaw in this analysis stems from the large difference between what a company might pay for the rights to oil still in the ground, compared to its ultimate value to both the resource owner and society once produced. Fundamentally, that value is much higher than the externality cost of the greenhouse gases that would be emitted along the way. If that weren't true, Europeans wouldn't pay the equivalent of $293/bbl to fuel their cars. Even if the oil in question were only worth today's long-dated futures price of around $75/bbl less production costs and a discount for quality versus West Texas Intermediate, the price of emissions offsets would have to approach at least $100/ton CO2 before the Ecuadoran government would be truly indifferent to leaving it undeveloped. At $100/ton, many other emissions reduction strategies would look more attractive, including the brute-force, industrial capture and sequestration of CO2 from smokestacks. However high the parasitic energy cost of such CCS, it would still allow most* of the energy content of fossil fuels to be applied to providing the global economy with electricity or transportation fuels, until other sources can expand enough to replace them.

The Washington Post article on this story concludes with a quote from a program director at the Nature Conservancy who characterized the idea as "probably ahead of its time." I'd go the next step and suggest that its inherent contradictions render it generally impractical. There are many reasons to forgo the development of some oil, and if Ecuador's Yasuni National Park is truly the marvel of biodiversity and unspoiled wilderness described, then leaving its oil untouched shouldn't require financial inducements extrapolated from guesses about the resources under its surface. At the same time, it's hard to see a country contemplating development of a less sensitively situated hydrocarbon resource being able to raise enough money from the sale of emissions offsets to make up for the opportunity cost of forgone profits, royalties and taxes from a production-sharing contract, not to mention the employment and other benefits to the national economy. Schemes like this shouldn't distract us from the urgent and important work of figuring out how to make true carbon capture and sequestration practical and cost-effective.

*(A good friend pointed out that my use of "most" here could be miscontrued to imply 90% or more. In fact, current estimates indicate that CCS would consume 1/4-1/3 of the energy output of a fossil-fuel fired power plant. That's consistent with the thermodynamics of combustion and CO2.)

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Zombie Project?

A year ago, the FutureGen partnership to build a prototype low-emissions coal power plant incorporating gasification and carbon capture and sequestration (CCS) technology looked dead in the water. Now, according to Technology Review, it may be on the verge of revival. A cynic would point out that a project sited in the home state of the new President might be a little harder to kill than most. It also can't hurt that Illinois's senior Senator stands high in the leadership of the majority party. However, there may be objective reasons to carry on with the project, particularly if the cost assessments that led to its "restructuring" were flawed, as suggested in a report issued recently by the General Accounting Office. Moreover, although major R&D projects ought to be carried out as efficiently as possible, I'm not sure that project costs should be the primary criterion for evaluating a one-off proof of concept, especially for such a crucial technology.

At its estimated cost of $1.8 billion for a 275 MW power plant, FutureGen must be the most expensive coal-fired power plant project in the world, for its size. That equates to $6500/kW of capacity, roughly triple the cost of a conventional coal plant and six times the cost of the combined-cycle gas-turbine unit that its core power block resembles. In normal utility service it could never compete with the cost of power from other technologies. If the project is successful, it should produce reliable power for many years, but as a byproduct of its principal purpose, which is to demonstrate a fully-integrated process for reducing the greenhouse gases and criteria pollutants from fossil-fuel power plants to the maximum extent possible. While all of the elements of this system, involving the gasification of coal to produce hydrogen, combustion of hydrogen in a gas turbine, and the capture and sequestration of CO2 from flue gas have all been demonstrated separately, with some of these elements in routine industrial and oil-industry service, integrating them at scale and running them together to determine the suitability of such a system for wider deployment has not.

As I described recently, CCS is a key technology for addressing climate change and for holding down the cost of large-scale reductions of emissions, once we've harvested the low-hanging fruit of energy efficiency and methane destruction. That doesn't mean FutureGen should be given a blank check, unless the new management at the Department of Energy can convince themselves that, particularly in light of all the work already done on this project, it represents the quickest and most effective next step in proving the technology. In particular, they should assess whether FutureGen includes outcomes beyond a proven prototype CCS power plant, such as opportunities to transfer technology elements to improve the efficiency or cost of other new and existing facilities. For example, could it improve existing integrated gasification combined cycle (IGCC) designs to increase their efficiency advantage over supercritical pulverized coal and other conventional coal technology, and thus reduce emissions even without full CCS? Could it advance our knowledge concerning the retro-fitting of CCS to existing power plants? If the answers to these questions look promising, then FutureGen deserves reviving, even if that creates the appearance of home-state favoritism.

Note: Energy Outlook will be on vacation for a few days. New postings should resume next Wednesday or Thursday.

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Building the Low-Emissions Future

Last week The Economist published a detailed assessment of the state of play for capturing and storing the carbon dioxide emitted by power plants and factories. Although it skirted the assertion of many environmentalists that "clean coal" is inherently an oxymoron, the article's tone was generally skeptical concerning the cost and ultimate efficacy of the technology. Coincidentally, Greenpeace released a study featuring an ultra-low-carbon scenario created in conjunction with the European Renewable Energy Council. It proposes that by 2050 the US could shed all coal-fired power generation, as well as all nuclear power and most natural gas-fired power, along with nearly 80% of the petroleum used in transportation--all replaced by renewable electricity and biofuels. If the Economist regards carbon capture and sequestration (CCS) as "expensive and unproven", I can only imagine the terms it might use to describe the extraordinary transformation required to achieve the outcome Greenpeace envisions. The necessity of reducing greenhouse gas emissions dramatically by mid-century and the serious obstacles to replacing our entire energy economy with renewable energy sources in that time frame reinforce the importance of continuing to pursue CCS, in spite of its uncertainties.

I've been following CCS for a long time, and I've written about it many times on this blog. Without diminishing the technical challenges involved, I see them as being manageable with existing and foreseeable engineering know-how, without a scientific breakthrough. I attribute the prolonged absence of a large-scale demonstration of fully-integrated CCS on energy sources more carbon-intensive than natural gas to the mismatch between its costs and current monetary benefits. Whether the cost proves to be closer to the low or high end of the range of estimates included in the article, from roughly $40-115 per ton of captured CO2, it's hard to imagine a utility or oil company taking on the investment and operating expenses involved without the incentive of a transparent and fairly predictable price on carbon emissions. Whatever the cost of CCS might be, it can't be considered in a vacuum, and that is the biggest shortcoming of the Economist's otherwise thorough analysis.

As the US Congress prepares to embark on its latest effort to enact a greenhouse gas cap and trade bill, it's important to think about where its enormous pool of emissions savings will be found, and at what cost. CCS is only one option among many. Happily, a fair amount of work has been done in this regard, including a study by McKinsey & Co. for the Conference Board a little more than a year ago. A key chart from their report portrays a potential medium-term supply curve for emissions reductions. It indicates that while there might be a number of ways to cut CO2 at low or even negative cost--changes that would pay for themselves--achieving deeper cuts would require the contribution of costlier solutions, including CCS.

It's also worth noting that the current cost per ton of CO2 reductions from some of our current climate change strategies exceeds most estimates for CCS. In my recent posting on the application of energy storage to solar power, I calculated an effective cost of power for a couple of utility-scale solar projects in Florida at around $0.25/kWh. That's a premium of at least $0.20/kWh compared to a coal-fired power plant (without sequestration.) Based on typical emissions of 2.1 lb. of CO2 per kWh generated from coal, that implies an abatement cost of $190/ton of avoided CO2. In the likelier event that the power backed out by solar was generated from natural gas, the effective abatement cost could be even higher, because of the smaller emissions savings involved, despite the higher cost of gas-fired power compared to coal.

That comparison doesn't imply that solar power will always be a high-cost source of emissions reductions, or that CCS represents some kind of silver bullet for climate change. At the same time, coal now accounts for 23% of US primary energy consumption, 49% of our electricity generation, and nearly two-thirds of our baseload-capable generation. The difficulty of replacing baseload power with cyclical or intermittent sources makes me very skeptical of any low-emissions scenario that ignores CCS or assumes we can jettison coal entirely, not to mention forgoing nuclear power, the second-largest baseload power source in the US and by far our largest source of low-CO2 power. My specific comments on the Greenpeace scenario are posted elsewhere. At a minimum, any claims that it proves we can achieve the administration's 2050 emissions goals with only "green" energy options and efficiency gains are unwarranted. As useful as they are, scenarios can only point the way to possible futures. They can't provide firm proof of anything.

That leaves us with the hard work of cobbling together a broad set of climate solutions, in response to a price signal on emissions. In my assessment, that mix is very likely to include awkward elements such as CCS, along with deeply unglamorous things like improved farming and ranching practices. Contrary to the conclusions of the editorial accompanying the article on CCS, the technology is worth pursuing for reasons that have nothing to do with "placating the coal lobby." Nor does the cost of proving its feasibility look so high as to "deprive potentially cheaper methods of cutting emissions of cash and attention," particularly when the administration expects to carve out $120 billion for energy R&D from the proceeds of cap & trade over the next ten years. And even if it did, it's one of the few options that could be applied to reduce directly the emissions from the fossil fuels that still account for 85% of the energy we consume. That could make the difference between a manageable transition to a low-emissions world and an upheaval as bad as the current financial crisis.

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Artificial Carbon Cycle

Part of the research for my writing and consulting involves watching for trends or common themes, and one that I've been picking up from diverse sources reflects a growing skepticism about "clean coal" and the processes for capturing and sequestering carbon (CCS) that are central to it. To get a flavor for this, Google on "clean coal" and "oxymoron". Some of these concerns are grounded in the science of thermodynamics, while the balance seem to reflect the long-standing attitude of environmentalists toward the coal industry, which would be the primary beneficiary of a practical CCS scheme. It's worth taking a few minutes examining why CCS is unlikely to be easy, but why, if it can be done cost-effectively on an industrial scale, it would be so beneficial.

It helps to think about CCS in the context of the earth's carbon cycle, in which carbon is exchanged through natural processes among the land, ocean, atmosphere, and living things. The principal issue in anthropogenic climate change is that our activities have upset the balance of this natural cycle, overloading it through the rapid release of vast quantities of stored carbon that had accumulated over geological time in fossil fuels. The goal of climate policy is to reduce the magnitude of that overload and eventually eliminate it by using carbon-intensive energy sources much more efficiently, while working to replace them with carbon-neutral or carbon-free energy. That's why biofuels, wind and solar power are regarded as essential elements of climate change mitigation, though it turns out that current biofuels are not remotely carbon-neutral. The idea behind CCS is to complement the main climate change mitigation strategies by creating an artificial version of the carbon cycle, in which the carbon released from the combustion of fossil fuels is collected and returned to long-term storage, before it can enter the natural carbon cycle.

That sounds simple enough, but to understand why it's so hard to do, consider the amount of coal necessary to produce one kilowatt-hour of electricity. In 2007 the US burned a little more than a billion tons of coal to generate just over 2 trillion kWh of electricity, for an average of 1.0 lb./kWh. Because most of the energy from coal derives from its carbon content, the main chemical reaction involved is very simple: C + O2 → CO2. So unlike the sulfate (SOx) or nitrate (NOx) pollution we have managed for decades, CO2 is neither the result of a fuel impurity nor an inadvertent byproduct of combustion, but rather its primary outcome, along with heat. On average, every lb. of coal yielding a kWh of electricity also emits 2 lb. of CO2 to the atmosphere. In other words, the mass of CO2 leaving coal-fired power plants is double the mass of coal that went in. That's a lot of gas to separate, compress, transport, and dispose of in geological or other storage.

Now consider the energy balance of such a system. Before adding CCS at the back end, you had to mine the coal, ship it to the power plant and burn it, producing heat that was used to make steam to turn a turbine that generated power. The typical thermal efficiency of such a facility is 35-45%, depending on coal quality, plant design and operation. But CCS is inherently energy-intensive, reducing the overall efficiency and the energy return on energy invested (EROEI) for the entire coal-to-power process. If separating the CO2 from the flue gas, compressing it, and putting it back into the ground at some remote location consumes up to a third of the energy generated from the coal, as some estimates suggest, then our artificial carbon cycle doesn't look very impressive, as a net energy source. After referring to the First and Second Laws of Thermodynamics, you might even wonder whether we could produce enough net energy from such a loop to be worthwhile, at all.

I had a hard time finding the EROEI of the standard coal-fired power lifecycle. It appears to fall in the range of 5:1 to 9:1, which compares favorably with conventional oil production and refining, and with the best renewable energy sources. If CCS reduced those returns by one-third, then while the energy balance would remain positive in a physics sense, the economics of some applications might become marginal, because CCS would consume a large helping of the energy surplus that coal-fired power normally creates. Another way to look at that is that the portion of the energy surplus thus consumed was attributable to the non-monetized externality of putting a greenhouse gas into the atmosphere, and thus not sustainable, anyway.

As daunting as all this sounds, there may be some clever ways to overcome the toughest impediments to getting started rounding up the carbon from coal power and stashing it back in the earth. In a new study, a team from MIT has proposed "partial capture": removing only enough CO2 from the flue gas to cut the emissions from a coal-fired power plant to the level of one running on natural gas, about a 35% reduction. This would allow CCS to be introduced incrementally, at a much lower investment cost and a less severe efficiency penalty than full CCS. And as I discussed in another posting, using captured CO2 to enhance the output from productive oil fields creates a positive value for it that offsets at least some of the cost of collecting and transporting it. Work at a Canadian oil field that does this suggests that the stored CO2 can be effectively monitored underground. Even more intriguingly, naturally-occurring mineral deposits called peridodites can act as CO2 sponges. These might be used to increase the efficiency of direct CCS, or to establish indirect CCS--a coal-scale emissions offset that would remove CO2 from the atmosphere without requiring a CO2 pipeline from the emissions source.

Easy or difficult, our motivation for pursuing CCS, instead of abandoning coal as incompatible with alleviating climate change, is based on the reality that we still derive roughly half of our electricity from coal and only about 1% from wind, solar and geothermal power. That means that our annual additions of renewable generating capacity are not yet covering the roughly 1.5% per year growth in US electricity demand we've experienced over the last 5 years, let alone taking market share away from coal or any other carbon-based fuel. Could we advance efficiency and renewables rapidly enough to displace a sizable fraction of our coal use within 10-20 years? Perhaps, though I'd feel a lot more confident about meeting the aggressive emissions-reductions targets the US is likely to take on within the next year or two, if we could tackle coal's emissions directly with CCS.

I'd like to wish my US readers a Happy Thanksgiving. Postings will resume on December 1.

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