Showing posts with label sustainability. Show all posts
Showing posts with label sustainability. Show all posts

Tuesday, April 22, 2014

ExxonMobil Confronts the Carbon Bubble

  • Companies and investors are squaring off over the potential impact of government climate policies on asset values, particularly in the fossil fuel industry.

  • ExxonMobil gave its shareholders data and assurances of asset resilience under various policies but dismissed the scenario of greatest interest to sustainability investors.

Last fall I devoted a lengthy post to the notion that future policies to address climate change expose investors in companies producing fossil fuels to a potential bubble in asset valuations. So although I am not an ExxonMobil shareholder, I was particularly interested when the company issued a report last month responding to specific shareholder concerns along these lines. Although the term “carbon asset bubble” did not appear in the report, its references to carbon budgets and the risk of stranded assets in a low-carbon scenario were aimed directly at this emerging meme.

Unsurprisingly, ExxonMobil’s management reassured investors that, “none of our hydrocarbon reserves are now or will become ‘stranded’.” Wisely avoiding past tendencies to question interpretations of climate science, their analysis appears to be grounded in mainstream views of climate change. It focuses on the costs and achievability of an extreme low-carbon scenario, and on the resilience of the company’s portfolio under various climate policies.

Exxon's analysis is based on the company’s latest Outlook for Energy, an annual global forecast broadly similar to the main “New Policies” scenario of the International Energy Agency (IEA). It has fewer similarities to the IEA’s “450″ scenario that underpins carbon bubble claims. The company expects energy demand to grow at an average of about 1% annually over the next three decades–faster than population but much slower than the global economy–with increasing efficiency and a gradual shift toward lower-emission energy sources: Gas increases faster than oil and by more BTUs in total, while coal grows for a while longer but then shrinks back to current levels. Renewables grow fastest of all, producing about as much energy in 2040 as nuclear power does today. As a result of these shifts global greenhouse gas (GHG) emissions peak around 2030 and then decline gradually.

That forecast won’t impress those advocating prompt and aggressive changes in the global energy mix to head off serious climate change, but it is not very different from the most recent global forecast of the US government’s Energy Information Administration. If anything, Exxon expects slower growth of energy and emissions than the EIA.

Ultimately, ExxonMobil's argument that it isn’t running outsized carbon asset risks depends heavily on its estimate of the implicit costs of achieving a much deeper and more rapid transition to renewables, compared to its--and others’--forecasts. It gauges this on the intensity of governments’ future climate policies, expressed in terms of their effective cost per ton of CO2 abated, and on the affordability of such measures to energy consumers, especially in the developing world, where emissions are increasing rapidly.

Without directly disputing the technical feasibility of achieving such large and rapid emissions cuts, the company's management essentially questions whether any government would or could impose the extraordinary costs necessary for that to occur. Their proxy estimate of $200/ton of CO2 for such policies is sobering. Even if the sums that would raise were all efficiently recycled by those governments–a heroic assumption–the resulting diversion of investment and increase in energy costs would adversely affect overall economic development.

The sustainable investor groups that raised this issue with ExxonMobil were apparently disappointed with the answer they got. That's not surprising, but having participated in similar exercises at Texaco, Inc., I think ExxonMobil went well beyond the kind of perfunctory reply the investors might have expected. In particular, it has provided enough data to support a more serious dialog with investors on this subject.

For example, Exxon indicated that it “stress tests” its projects and acquisitions at proxy costs of up to $80/ton of CO2, compared to current levels of $8-10/ton in the EU’s Emission Trading System. Implicit in that is the question of whether investors would reasonably expect them to test projects at $200/ton., which would equate to around $100 per average barrel of oil--roughly today's price--based on the nifty “seriatim” chart at the end of the report.

The document also includes information addressing the resiliency of the company’s assets and operations under a lower-carbon future, with their emphasis on natural gas and a global average cost of production under $12 per oil-equivalent-barrel (BOE). Climate policies would have to raise those costs and shrink the associated revenues very significantly to jeopardize current production, nor are low oil prices generally consistent with a low-carbon world. Investments in future production are another matter, though Exxon refers to the IEA’s 450 scenario to demonstrate how much additional oil and gas development would still be required in the next 20 years, even in a world that was determined to constrain global temperature increases to no more than 2°C.

ExxonMobil’s response to investors will not end the debate over the carbon bubble. While providing a lot of information, the company essentially argued that the extreme low-carbon scenario associated with the risks of a carbon bubble is irrelevant, because it can’t be achieved any time soon, irrespective of the risks associated with current emissions levels. That is close to my own view, but it is unlikely to resonate with those who are more focused on the risks of climate change than on the nuts and bolts of what it would take to avert them.

Interestingly, the company’s report on carbon risks was issued on the same day as the latest iteration of the predicted consequences of further warming from the Intergovernmental Panel on Climate Change (IPCC). In a sense each report provides context for the other, so that investors who accept the IPCC’s analysis can weigh the potential costs of global warming against the cost and scale of the changes that would be required to put the world on a crash program to avert the worst climate-change-related outcomes. They can then buy or sell accordingly.

A different version of this posting was previously published on Energy Trends Insider.

Friday, November 22, 2013

Five Myths About the "Carbon Asset Bubble"

  • The idea that efforts to mitigate climate change expose fossil fuel assets to the risk of a bubble-like collapse has attracted some high-profile supporters.
  • However, the notion of a "carbon bubble" depends on questionable assumptions concerning our current knowledge of climate change, the rate of adoption of renewable energy technology, and how such assets are valued.
In their recent Wall St. Journal op-ed, Al Gore and one of his business partners characterized the current market for investments in oil, gas and coal as an asset bubble. They also offered investors some advice for quantifying and managing the risks associated with such a bubble. This is a timely topic, because I have been seeing references to this concept with increasing frequency in venues such as the Financial Times, as well as in the growing literature around sustainability investing.

Although bubbles are best seen in retrospect, investors should always be alert to the potential, particularly after our experience just a few years ago. In this case, however, I see good reasons to believe that the case for a “carbon asset bubble” has been overstated and applied too broadly. The following five myths represent particular vulnerabilities for this notion:

1. The Quantity of Carbon That Can Be Burned Is Known Precisely
Mr. Gore is careful to differentiate uncertainties from risks, which he distinguishes for their amenability to quantification. For quantifying the climate risk to carbon-heavy assets, he refers to the widely cited 2°C threshold for irreversible damage from climate change, and to the resulting “carbon budget” determined by the International Energy Agency (IEA). As Mr. Gore interprets it, “at least two-thirds of fossil fuel reserves will not be monetized if we are to stay below 2° of warming.” That would have serious consequences for investors in oil, gas and coal.

The IEA’s calculation of a carbon budget depends on a factor called “climate sensitivity.” This figure estimates the total temperature change resulting from a doubling of atmospheric CO2 concentrations. The discussion of climate sensitivity in the recently released Fifth Assessment Review of the Intergovernmental Panel on Climate Change (IPCC) sheds more light on this parameter, which turns out not to be known with certainty. Their Summary for Policymakers includes an expanded range of climate sensitivity estimates, compared to the IPCC’s 2007 assessment, of 1.5°-4.5°C with a likelihood defined as 66-100% probability. It also states, “No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.”

The draft technical report that forms the basis for the Summary for Policy Makers provides more detail on this. It further assesses a probability of 1% or less that the climate sensitivity could be less than 1°C. That shouldn’t be surprising, since temperatures have already apparently risen by 0.8°C above pre-industrial levels. At the same time, the report indicates that recent observations of the climate — as distinct from the output of complex climate models — are consistent with “the lower part of the likely range.”

In other words, while continued increases in atmospheric CO2 resulting from increasing emissions are widely expected to result in warmer temperatures in the future, the extent of the warming from a given increase in CO2 can’t be determined precisely before the fact. For now, at least, the CO2 level necessary to reach a 2°C increase would be consistent with calculated carbon budgets both larger and smaller than the IEA’s estimate. That means that the basis of Mr. Gore’s suggested “material-risk factor” — as distinct from an uncertainty — is itself uncertain.

2. The Transition to Low-Carbon Energy Is Occurring Fast Enough to Threaten Today’s Investments in Fossil Fuels
There is no doubt that renewable energy sources such as wind and solar power are growing at impressive rates. From 2010 though 2012 global solar installations grew by an average of 58% per year, while wind installations increased by 20% per year. Yet it’s also true that they make up a small fraction of today’s energy production, and that the risks for investors of extrapolating high growth rates indefinitely proved to be very significant in the past.

For further clarity on this, consider the IEA’s latest World Energy Outlook, the agency’s analysis of global energy trends, which was just released on November 12. The IEA projects global energy consumption to grow by 33% from 2011 to 2035 in its primary scenario, which reflects expanded environmental policies and incentives over those now in place. In that scenario, the global market share of fossil fuels is expected to fall from 82% to 76%, but with total fossil fuel consumption still growing by 24% over the period. Only in their “450″ scenario, based on similar assumptions to its carbon budget, would fossil fuel consumption fall by 2035, and then only by 11%.

Moreover, in its April 2013 report on “Tracking Clean Energy Progress,” the IEA warned, “The drive to clean up the world’s energy system has stalled.” This concern was based on their observation that from 1990 to 2010 the average carbon dioxide emitted to provide a given unit of energy in the global economy had “barely moved.” That’s hardly a finding to be celebrated, but it serves as an important reminder that while some renewable energy sources are growing rapidly, fossil fuel consumption is also growing, especially in the developing world — and from a much larger base.

The transition to lower-carbon energy sources is inevitable. However, it will take longer than many suppose, and it cannot be accomplished effectively with the technologies available today. That’s a view shared by observers with better environmental credentials than mine.

3. All Fossil Fuels Are Equally Vulnerable to a Bubble
As Mr. Gore correctly notes, “Not all carbon-intensive assets are created equal.” Unfortunately, that’s a distinction that some other supporters of the carbon asset bubble meme don’t seem to make, particularly with regard to oil and natural gas. The vulnerability of an investment in fossil fuel reserves or hardware to competition from renewable energy and decarbonization doesn’t just depend on the carbon intensity of the fuel type — its emissions per equivalent barrel or BTU — but also on its functions and unique attributes.

The best example of this might be a recent transaction involving the sale of a leading coal company’s mines. What’s behind this wasn’t just new EPA regulations making it much harder to build new coal-fired power plants in the US, but some fundamental, structural challenges facing coal. Power generation now accounts for 93% of US coal consumption, as non-power commercial and industrial demand has declined. This leaves coal producers increasingly reliant on a utility market that has many other--and cleaner--options for generating electricity. That’s particularly true as the production of natural gas, with lower lifecycle greenhouse gas emissions per Megawatt-hour of generation, ramps up, both domestically and globally. Coal accounts for about half of the global fossil fuel reserves that Mr. Gore and others presume to be caught up in an asset bubble.

Compare that to oil, which at 29% of global fossil fuel reserves, adjusted for energy content, still has no full-scale, mass-market alternative in its primary market of transportation energy. Despite a decade-long expansion, biofuels account for just over 3% of US liquid fuels consumption, on an energy-equivalent basis. They’re also encountering significant logistical challenges and concerns about the degree to which their production competes with food. This has contributed to efforts in the EU to limit the share of crop-based biofuels to around 6% of transportation energy. Biofuels have additional potential to displace petroleum use, particularly as technologies for converting cellulosic biomass become commercial, but barring a prompt technology breakthrough they appear incapable of substituting for more than a fraction of global oil demand in the next two decades.

Electric vehicles offer more oil-substitution potential in the long run, though they are growing from an even smaller base than wind and solar energy. Their growth will also impose new burdens on the power grid and expand the challenge of displacing the highest-emitting electricity generation with low-carbon sources.

Meanwhile, natural gas, at 20% of global fossil fuel reserves, offers the largest-scale, economic-without-subsidies substitute for either coal or oil. In any case, it has the lowest priority for substitution by renewables on an emissions basis, and so should be least susceptible to a notional carbon bubble.

4. A Large Change in Future Fossil Fuel Demand Would Have a Large Impact on Share Prices
Although Mr. Gore’s article includes a good deal of investor-savvy terminology, it is entirely lacking in two of the most important factors in the valuation of any company engaged in discovering and producing hydrocarbons: discounted cash flow (DCF) and production decline rates. Unlike tech companies such as Facebook or even Tesla, the primary investor value proposition for which depends on rapid growth and far-future profitability, most oil and gas companies are typically valued based on risked DCF models in which near-term production and profits count much more than distant ones.

At a conservative discount rate of 5%, the unrisked cash flow from ten years hence counts only 61% as much as next year’s, while cash flow 20 years hence counts only 38% as much. Announced changes in near-term cash flow due to unexpected fluctuations in production or margins would normally be expected to have a much bigger impact on share prices than an uncertain change in demand a decade or more in the future.

This is compounded by the decline curves typical of many large hydrocarbon projects. If the first 3-5 years of a project account for more than half its undiscounted cash flows, it won’t be very sensitive to long-term uncertainties, nor would a company made up of the aggregation of many projects with this characteristic. This is even truer of shale gas and tight oil projects, which yield faster returns and decline more rapidly.

I can’t speak for Wall Street's oil and gas analysts, but I’d be surprised based on past experience in the industry if the risk of a 10% or greater drop in global demand for oil or gas in the 2030s would have much of an effect on their price targets for companies — certainly not enough to qualify as a bubble.

5. Fossil Fuel Share Prices Don’t Already Account for Climate Risks
The assertion of a carbon bubble in fossil fuel assets ultimately depends on investor ignorance of climate-response risks, presumably because companies haven’t quantified those risks for them. To the extent the latter condition is true, it represents an opportunity for companies seeking to capitalize on the boom in sustainability-based investing.

However, you needn’t be an adherent of the Efficient Markets Hypothesis for which Eugene Fama was named as a recipient of this year’s Nobel Prize in Economics to realize that thanks to the Internet, average investors have access to most of the same information on this subject as Mr. Gore and his partners. Institutional investors, who make up the bulk of the shareholding for at least the larger energy firms, and the analysts who follow these companies have the resources to access even more information.

Nor is the idea of a carbon bubble exactly new. Mr. Gore didn't create it, and I’ve been following it for a couple of years, as it took over from waning interest in Peak Oil. It’s not an obscure risk, either, in the sense that sub-prime mortgages and credit default swaps were in the lead-up to the failure of Lehman Brothers in 2008. It’s becoming more mainstream every day, although the burden of proof that this risk is mispriced rests with those advocating this view.

Before concluding, a word of disclosure is in order. As you may gather from my bio, I spent many years working with and around fossil fuels, though my ongoing involvement in energy is much broader than that. As a result of that experience, my portfolio includes investments in companies with significant fossil fuel holdings. I strive for objectivity, but I can’t claim to be disinterested. However, neither can Mr. Gore. As a major investor in renewable energy and other technologies through the firm cited in the article and other roles, he has as much at stake in promoting the idea of a carbon bubble — and on a very different scale — as I might have in dispelling it.

The carbon bubble is an interesting hypothesis, even if I don’t yet find the arguments made in support of it convincing. Despite that, I see nothing wrong with investors wanting to track their carbon exposure, consider shadow carbon prices, or ensure they are properly diversified. However, the biggest risk I see that might eventually warrant considering divestment of fossil-fuel-related assets isn’t based on the merits of this analysis, but on the possibility of creating a self-fulfilling prophesy by means of drumming up social pressure on institutional investors. You might very well think that applies to this Wall St. Journal op-ed. I couldn’t possibly comment.

A different version of this posting was previously published on Energy Trends Insider.

Monday, December 06, 2010

Turning Biomass into Power or Fuel

This morning I ran across a news item indicating that Dow Chemical was installing a biomass cogeneration unit at its facility in Aratu, Brazil to provide process steam with minimal greenhouse gas emissions. It's a good example of another way to convert biomass into energy that hasn't attracted nearly as much interest as advanced biofuels have. That's somewhat surprising, since biomass power shares most of the logistical limitations but few of the technical challenges that have made the production of biofuel from non-food biomass so difficult. Perhaps the relative neglect of biomass power results more from motivation than outcomes.

I'm sure I paid more attention to this story because of Dow's choice of eucalyptus as the biomass source. I grew up under the spreading limbs of a giant eucalyptus tree in California--limbs that periodically fell off in storms, including a 9-ton monster that practically cut our house in half. In the years before that tree was finally cut down I raked up enormous quantities of the eucalyptus leaves and nuts that bombarded our yard. It would be fair to say that I developed a strong distaste for the species, at least for the ornamental and wind-break purposes for which many Californians had chosen this Australian import. However, many of these same features, including its fast growth and dense, oily wood, seem to be good attributes for biomass supply.

As noted in a recent Wall St. Journal article, the Achilles heel of biomass power is logistics. The lower the energy density of the biomass, relative to the fossil fuels it is intended to replace, the closer the source must be to the facility where it will be used, before transportation erodes any cost benefits, even after considering emissions reductions. Wood chips provide about 2/3 as much energy per pound as bituminous coal, but they can take up more than six times as much volume, unless they are first dried and turned into pellets. As is the case for cellulosic biofuels, these supply-chain considerations limit the scale of biomass power application and impose an additional constraint of sustainability: It doesn't pay to build a biomass power plant (or a cellulosic biofuel plant) unless you can be sure of a long-term supply of the raw material. The Journal article included examples of projects that paid a high price for miscalculations in this regard. One strategy for mitigating this limitation is co-firing, which relies on biomass for only a portion of a power plant's fuel needs.

The lower energy density of biomass also makes it essential to extract as much energy as possible from each pound or cubic foot. One of the reasons for the high efficiency of the Brazilian ethanol industry is that many of its mills turn the bagasse, the waste left over after extracting the juice from sugar cane, into process heat and power and need little or no fossil energy. Burning biomass in a high-efficiency combined heat and power application, as the Dow project appears to do--based on the scant information I could find--provides another way to get the most bang for the biomass buck.

That brings us back to motivation. One of the main justifications for the pursuit of cellulosic biofuels is that we have relatively few practical, cost-effective alternative fuels that could replace more than a small fraction of our petroleum use. On the other hand, we have many ways to generate electricity, including more than a few that emit little or no greenhouse gas, one of the main benefits of biomass power--though this point is not without controversy. However, I can't help wondering whether in the long run the best way to turn non-food biomass into energy for vehicles is to turn it into electricity first, rather than working so hard to break down plant structures that have evolved over millions of years to resist easy conversion into chemical energy. Resolving that dilemma depends on a lot more than engineering considerations, however, since we still don't know much about how consumer preferences will play into it. In the meantime, projects like Dow's provide another option for reducing emissions from facilities that must meet increasingly stringent sustainability criteria.

Thursday, April 29, 2010

Energy from All Around Us

It's somewhat ironic that the long-awaited approval of the Cape Wind offshore wind project by the Department of Interior (DOI) should come in the same week that the nation's attention is focused on the problems of another, more traditional offshore energy project. Although the renewable electricity from the former scarcely substitutes for petroleum from the latter, Cape Wind is nevertheless emblematic of an intentional shift from energy sourced far away, in places like the deepwater Gulf of Mexico, to energy derived from sources all around us. If Secretary Salazar had turned it down, it would have cast serious doubts on the administration's entire clean energy agenda. However, concurrence with this one project doesn't answer all questions concerning the larger shift, of which it represents just a small component. Similar issues are bound to come up with increasing frequency as the transition to new energy continues.

Cape Wind and the Macondo prospect that the Deepwater Horizon rig was drilling into represent opposite poles of the energy spectrum, and not just because the latter is now leaking oil into the marine environment at a rate that the latest estimate puts at 5,000 barrels per day, much higher than initially thought. Cape Wind would tap into the clean and renewable, but extremely diffuse energy sources that surround us. After taking into account the restrictions imposed by DOI, its 130 turbines would on average generate as much electricity as a gas turbine power plant consuming a quantity of natural gas equivalent to 6,000 bbls/day of oil. In other words, it takes a very large array of offshore wind turbines to match the energy in the oil currently leaking from a single well. Platforms similar to what BP might have been planning to install after successfully completing the exploration of Macondo routinely produce up to 20 times that much oil.

The implications of this huge difference in energy density are clear. Without the energy concentration that nature has embedded in fossil fuels over many millennia, the hardware required to tap natural energy flows in real time becomes vast in extent. Generating 20% of US electricity needs from wind, which some see as just the beginning, will ultimately require more than 8 times as much wind capacity as the 35,000 MW installed as of the end of last year, even if US electricity demand remains static in the interim. Solar power, which last year generated just 0.02% of our electricity, would have to increase by a much larger factor. This is one of many reasons that increased reliance on nuclear power is such an important element of the transition to more sustainable energy sources, because nuclear--and to a lesser extent geothermal power--represents a critical source of highly-concentrated, low-emission energy. The more nuclear in the mix, replacing baseload coal, the less we must rely on distributed energy gathered in our immediate vicinity.

In any case, in order to obtain a much larger portion of our energy diet from sources like onshore and offshore wind and solar power, projects like Cape Wind must go from being rarities to ubiquitous features of our seascapes and landscapes. The opposition to Cape Wind that has delayed this project for years is focused on a central dilemma of that shift: Many of the same underlying trends that lead us to want to harness clean energy from wind, sunlight and geothermal heat have also increased our focus on the broadly-defined environmental impacts of doing so.

Our grandparents wouldn't have blinked at putting up tens of thousands of wind turbines, let alone the few hundred slated for Nantucket Sound. They'd have thought of them as signs of progress, just as they viewed oil derricks and power lines. It's incumbent on us to balance our more modern sensibilities related to the "viewscape" with fundamental environmental challenges of climate change and sustainability, as well as the need to sustain the energy supplies our civilization requires. Approving Cape Wind--whether it eventually gets built or not--is entirely consistent with those imperatives.

Tuesday, June 23, 2009

Sustainable Energy

I just ran a quick search on Google Trends to check my hunch that the phrase "sustainable energy" has become a lot more common, lately. That seems to be the case, at least based on the volume of news references tracked by Google. While I would regard a greater focus on sustainability as a positive development, I'm much less comfortable with its indiscriminate use as a synonym for "renewable". It's dangerously simplistic to think that the only parameters of sustainability that matter for a given energy technology are the extent of the energy supply it taps and the greenhouse gas emissions associated with its use. However understandable that might be in light of concerns about climate change and energy security, the complexities it obscures could ultimately prove just as limiting, in their own way, as the depletion of finite reserves of fossil fuels or the response of the global climate to increasing concentrations of carbon dioxide in the atmosphere.

Sustainable energy means different things to different people, as even a Wikipedia definition that points mainly to standard renewables admits. All too often, though, these definitions focus on the consumption of fossil energy sources and their accompanying emissions, while ignoring the use of other scarce resources, particularly water. In a recent posting I highlighted the high water consumption associated with the production of corn ethanol, a fuel widely regarded as more or less infinitely renewable, and thus much more sustainable than the oil it is intended to displace. Ironically, petroleum production and refining on average consume far less water per gallon or BTU of marketed fuel than most biofuels. The production of biofuels from non-food sources requiring little or no irrigation would alter that comparison, but still might not close this gap.

Biofuels aren't the only components of our energy mix that use lots of water. Electricity generation also consumes huge quantities, though much of it is returned downstream without degradation. Most thermal power plants use water for cooling and steam generation. That includes both fossil and nuclear power plants. Some renewable energy sources are also subject to this constraint, including solar thermal power, as noted in a recent Washington Post article. Enhanced geothermal power, which has great potential as a low-emission energy source, requires the injection of large volumes of water underground to create artificial hydrothermal reservoirs, and to transfer heat to the surface for power generation. In fact, at least 80% of the electricity generated in the US last year involved the use of water to some degree, a dependency that attracted critical attention during the Southeast drought in 2007.

Water is hardly the only input that should be considered in a broader view of sustainable energy. The consumption of rare earths and scarce metals in the production of thin-film solar panels, advanced batteries, wind turbine generators, and other aspects of the developing green-energy economy is starting to worry some experts. While I haven't delved into it in much detail, I'd be surprised if these factors proved limiting in the near term. After all, the technologies in question have only been around for a few years, so there hasn't been much time for the sources of these exotic ingredients to ramp up to support their growing demand. This scaling issue cuts both ways, however. For example, if solar energy is to expand from its present contribution of less than 1% of renewable power generated here last year to, say, 10% of our total power supply, the use of an ingredient in proportions as small as a hundred grams per kilowatt of capacity would translate into a cumulative requirement for tens of thousands of tons. If the substance in question was the Tellurium used in Cadmium-telluride solar cells, its global output would have to expand by at least 10X within a decade or two. That might not be possible, or at least economically feasible.

The point here is not to suggest that we're stuck in some depressing dynamic in which we encounter bottlenecks and unintended consequences in every direction we turn, as we seek alternatives to conventional energy. Instead, we need to remember that oil, gas and coal aren't the only finite substances in the earth's crust. We must consider all our energy options in terms of trade-offs, and not just with regard to the aesthetics of wind farms and solar panels in our back yards vs. oil derricks and central power plants in someone else's. The choices we are making demand a thorough look at their lifecycle impacts, including all the inputs and outputs along the way. That won't be easy, and it clearly will not be convenient for those sectors that have benefited from an overly narrow view of this issue, such as the interests that are supporting legislation to block the EPA from factoring in the effect of global land-use changes in the agency's lifecycle assessment of corn ethanol.

This broader view of sustainable energy is another reason to moderate our faddish focus on all things renewable, as I noted recently when I argued that we need a low-emission electricity standard, instead of a renewable electricity standard. Tackling climate change effectively will require clear goals that address outcomes, rather than preconceived notions about pathways. And when it comes to energy security, we need a framework that recognizes that oil in tankers is not the only energy-sector import that bears watching.