Friday, March 3, 2017

Clean fuels and climate leadership.

The past few days found me at this year's Climate Leadership Conference in Chicago, where I moderated a panel session entitled "Employing The Next Generation of Clean Fuels." This annual event brings together a diverse set of private companies who are pursuing strategies to reduce greenhouse gas (GHG) emissions with partners in nonprofit and government sectors.

The clean fuels panel was framed around the fact that transportation is now the nation's highest emitting sector in terms of greenhouse gases. It addressed how adopting alternative fuels or expanded electrification can reduce the GHG emissions stemming from personal and business travel. The other panelists were Rebecca Boudreaux of Oberon Fuels, a company that produces dimethyl ether (DME); Jon Coleman of Ford Motor Company; Angela Foster-Rice of United Airlines; and Ed Harte of Southern California Gas.

Most panelists focused on the opportunities and challenges associated with the particular fuel options they are pursuing. Both natural gas and DME are being targeted to replace petroleum-based diesel fuel in commercial vehicles. Airlines such as United have been testing biofuels, which have a significant role in the industry's international plan to avoid further growth in GHG emissions from air travel after the year 2020. As a manufacturer of vehicles for utilizing all of the major alternative fuels, Ford highlighted the need to carefully analyze the many factors that influence whether and to what extent a given alternative fuel might be adopted.

Not surprisingly, I sounded a note of caution about clean fuels and climate. What follows are my prepared remarks for the panel:

In terms of my own points to raise for our discussion, the first is that we need to clarify what is meant by a clean fuel from a climate perspective. Because carbon itself is an energy carrier, not just a waste product, the science is very different for climate mitigation than it is for traditional air pollution control.

It is common to equate clean fuel with alternative fuel, meaning a transportation fuel not derived from petroleum. However, petroleum fuels can now be burned very cleanly as far as criteria pollution is concerned. Low-sulfur gasoline with advanced catalytic converters enables vanishingly small levels of tailpipe emissions as seen in super-ultra-low emission vehicles, for example. Fuels with simpler molecules, such as methane or dimethyl ether, make it easier to achieve ultra-low emissions than complex hydrocarbon mixtures, especially in diesel engines. Nevertheless, criteria emissions no longer provide a strong reason for a major fuel transition.

Moreover, given the truly disruptive technology of fracking, the policy rationale to replace petroleum for economic or energy security reasons is also greatly diminished. That means that climate protection is the most important rationale going forward.

Now, plug-in electrification zeros out vehicle emissions, and so electric vehicles are inherently clean for both CO2 and conventional air pollutants. And that brings me to this next point. For climate, it comes down to this: does the fuel carry carbon to the vehicle or not? All practical combustion fuels are carbon based and so emit CO2 when burned, and there's no practical way to scrub CO2 from a tailpipe or jet exhaust. So as long as we're using liquid fuels, carbon control requires counterbalancing tailpipe emissions by speeding up the rate at which CO2 is removed from the atmosphere somewhere else.

There is no significant benefit to downstream substitution of one chemically carbon-based fuel for another. Rather, it's a matter of carbon dioxide removal, or so-called "negative emissions," in some upstream location outside the transportation sector.

This insight is crucial for understanding why biofuels have become so controversial. As far as climate is concerned, biofuels have no benefit when they are burned. Any potential benefit can only happen through additional carbon uptake somewhere upstream. And a key word here is "additional." Diverting existing biomass harvests, whether from forests or cropland, does not speed up how quickly carbon is removed from the atmosphere, and so offers no potential climate benefit no matter how efficient the biofuel production process might be.

Of course, if the fuel is literally carbon free, such as electricity or hydrogen, then the control problem is entirely upstream. Everyone gets that and indeed, shifting the carbon control upstream is part of the appeal.

To sum up, for transportation fuels and CO2, there are really just two types of mitigation options: reduce and remove. One can reduce liquid fuel demand by driving less and flying less, improving fuel economy or substituting electricity or hydrogen. The other option is to remove CO2 from the air somewhere else. That means investing in atmospheric carbon dioxide removal through terrestrial carbon management, and the all the rules governing carbon offsets come into play. The CO2 removal must be real, additional, verifiable, permanent and adjusted for leakage. And so for transportation and climate, offsets are not just a way to buy time or control costs. Because the need for liquid fuels isn't going to go away anytime soon, CO2 removal is real missing link in climate strategy and is just as fundamental as any clean tech option.

Thursday, February 2, 2017

A to-the-point radio interview on biofuels and climate

As a guest yesterday on the WEMU (89.1 FM from Eastern Michigan University) "Issues of the Environment" segment, I answered host David Fair's questions about how our recent work differed from the established lifecycle analysis methods used to analyze the greenhouse gas emissions impacts of biofuels.

The resulting interview has great questions from David and clear explanations from myself about why the results of government modeling of the issue are misleading and why, as far as climate is concerned, it's better to repeal biofuel policies and focus on reforestation and other ways to remove carbon from the air and sequester it on land.

Morning Edition: Issues of the Environment 
U-M Researcher Calls For End To Current Biofuel Policy In The U.S.


In August of 2016,  University of Michigan Energy Institute scientists, led by John DeCicco, released an 8-year study.  It estimated powering an American vehicle with ethanol made from corn increased carbon pollution more than using gasoline.  In this week's "Issues of the Environment,” David Fair talks with Professor DeCicco about the findings and what it means to future policy. 


Listen Here [10:09 mp3 link] 

Sunday, December 18, 2016

The need to speed up carbon uptake

Last week I gave a talk, entitled "Net Ecosystem Production and Actionable Negative Emissions Strategies," at the American Geophysical Union (AGU) fall meeting in San Francisco. It was presented in a session on negative emissions strategies, which refers to the topic of removing CO2 from the air in order to slow -- and hopefully one day reverse -- the buildup of carbon in the atmosphere.

Net ecosystem production (NEP) is the net rate at which carbon is taken up by a terrestrial ecosystem. It determines the amount of carbon that becomes available for some use (e.g., crop or timber harvest) or for sequestration on the land. Scientifically speaking, any parcel of land with living organisms on it is an "ecosystem," including farm land or managed forests as well as natural lands and parts of the built environment that aren't totally paved with sterile concrete.

Plants and other organisms that carry out photosynthesis in the terrestrial biosphere actively remove CO2 from the air. Thus, they provide a fundamental mechanism for pursuing negative emissions. However, to be meaningful for climate mitigation -- which is the sense in which the term negative emissions is used -- carbon must be removed from the air more quickly than it is already being removed. That's what "the need to speed up carbon uptake" means and for the terrestrial biosphere, that means increasing NEP.

The fact that terrestrial carbon management is an actionable ("here-and-now") strategy and that using it for negative emissions requires increasing NEP are the main points of my talk. It can be download here in PDF format including both the narrative and slide images.

Friday, November 11, 2016

A simple comparison of ABC to LCA results for corn ethanol

Our recent paper [1] provides an example that compares annual basis carbon (ABC) accounting results to typical lifecycle analysis (LCA) results for corn ethanol. As noted in the paper's discussion section, we used the same process GHG emissions as used in a standard LCA but then adjusted for the fact that biofuel combustion is not fully carbon neutral, as LCA assumes. The implication is then that corn ethanol is 27% more carbon intensive than gasoline instead of 44% less carbon intensive as was claimed by the LCA previously published by Wang et al [2]. This post describes how we made that comparison.

Monday, October 24, 2016

Carbon balance effects of real-world biofuel use

Most of the debate about the environmental merits of biofuel use has been based on lifecycle analysis (LCA). Also known as life-cycle assessment, carbon footprint analysis, "cradle-to-grave" analysis, or (in the case of motor fuels) "well-to-wheels" analysis, LCA is a method for adding up all of the impacts of interest associated with a product. It includes the effects of producing a product and its component materials, associated shipping and packaging effects (as relevant), the use of the product and any related disposal effects. For assessing climatic impacts, LCA tallies the greenhouse gas (GHG) emissions associated with the production, use and disposal of the product. When the product is a motor fuel, the numerical result of such LCA modeling is called the fuel's "carbon intensity," as calculated for California's Low-Carbon Fuel Standard (LCFS), for example.

A cornfield does not absorb CO2 from the atmosphere
any more quickly 
when it is used to make ethanol than
when it is grown for food or feed. 
This basic fact of 
carbon mass balance is ignored by the 
lifecycle studies
that claim climate benefits for biofuels. 
The question, "how does the overall emissions impact of using a biofuel such as ethanol compare to that of a fossil fuel such as gasoline?" seems straightforward, and sounds like something that LCA can answer. However, that question is actually ill-posed scientifically speaking. In other words, when one looks carefully at what actually happens when a given biofuel substitutes for a fossil fuel, it turns out that LCA cannot give a straightforward, unambiguous answer. Properly qualified, the answer will always be, "it depends." And it doesn't just depend on the particular fuel and how it is produced; it also depends on the design of the LCA model and the assumptions it invokes.

Thursday, September 29, 2016

U.S. biofuel consumption chart through 2015

Just to provide an updated picture of the rise in U.S. biofuel consumption, here's a chart based on the latest annual data from EIA's Monthly Energy Review (MER). 

As of calendar year 2015, U.S. ethanol consumption was 13.9 billion gallons per year, up from 1.7 billion gallons in 2000. In 2000, biodiesel consumption was below the level of significance for EIA reporting (i.e., statistically zero relative to overall U.S. motor fuel use). Biodiesel consumption reached 1.5 billion gallons in 2015, and so total biofuel consumption amounted to 15.4 billion gallons that year.

For context, U.S. motor gasoline consumption was 140 billion gallons and distillate fuel oil (which is mostly but not all highway diesel) was 61 billion gallons last year.

In terms of carbon, biofuels accounted for 4.7% of total direct CO2 emissions from the U.S. transportation sector in 2015.

A short URL for embedding this chart is: If you use it, please credit this blog. The source data can be downloaded as Tables 10.3 (for ethanol) and 10.4 (for biodiesel) from the Renewable Energy section of EIA's MER webpage.


Saturday, September 17, 2016

Tailpipes top smokestacks as nation's largest CO2 emitters

Transportation, which runs almost entirely on petroleum fuels, and electricity generation, which had used mainly coal, have long been the largest sources of CO2 emissions in the United States. Although power plant smokestacks exceeded motor vehicle tailpipes and other mobile sources such as aircraft in terms of CO2 emissions for nearly forty years, this year brings a crossover of these two emission trends. The CO2 emitted by the transportation sector has been greater than that from the power sector for seven of the past eight months, and so 2016 is on track to see mobility overtake electricity as the country's biggest contribution to global warming.

Friday, June 3, 2016

Will car companies do better than coal companies in embracing the climate challenge?

Today in Slate, Daniel Gross published a thought-provoking piece entitled "Could Coal Have Survived by Going Green?" It highlights how the industry itself contributed to its own demise not only by fighting environmental policies but also by failing to invest in ways to utilize coal much more cleanly.
The Cadillac Escalade: this one is as black as coal and its
tailpipe spews nearly nine tons of CO2 into the air per year.

Coal fueled the industrial revolution and even in this post-industrial era it still provides a bedrock source of energy for much of the world. Although now overtaken by natural gas for generating electricity in the United States, coal remains second only to oil as the world's largest source of commercial energy. Its low resource cost could give it a role even in an increasingly climate-constrained future. But for that to happen, the industry's leaders would have had to embrace carbon mitigation as a worthy, investment-stimulating challenge instead of spending down their dwindling political capital to fight the inevitable.

One can see some parallels here to the recent near-death crisis of U.S. domestic automakers. Although General Motors, Ford and Chrysler had often talked a green line and showed off a few token green-branded products, for many years their major investment and lobbying strategies emphasized evading energy and climate policies instead of embracing them.

Monday, May 23, 2016

Latest tweak to U.S. biofuel mandate is politically correct and ecologically cruel

EPA's new Renewable Fuel Standard (RFS) proposal modestly increases the amount of biofuel that America's cars and trucks have to consume next year but still keeps the total renewable fuel mandate below the Congressionally scripted target.

In the plan released on May 18, ordinary corn ethanol gets a 300 million gallon boost, biodiesel is bumped up by 100 million gallons and other so-called advanced biofuels see a 200 million gallon increase compared to last year's regulation. Nevertheless, the proposed 18.8 billion gallon total remains significantly lower than the 24 billion gallon goal for renewable fuel in 2017 that Congress wrote into law back in 2007.

EPA's approach reflects a compromise worked out last year after several tortuous years of regulatory delay. This "politically correct" strategy has the agency taking a middle road that balances the money-making interests of the biofuel industry and the corn and soybean lobbies against the engineering and economic realities that render ethanol and biodiesel such inferior motor fuels. Reactions to the proposal were predictable. The renewable fuel lobby and its allies complain "that's not enough" while the oil industry and other critics say "that's too much" biofuel.