Thinking about a regional liquid fuels carbon study

One way we might better understand the opportunities to counterbalance the carbon in liquid fuels is to assess the immediate opportunities in a given region. Being based in Michigan, a midwest regional scope makes sense for practical reasons. Such a scope is of particular research interest for several other reasons as well:

• Michigan, and the industrial midwest more generally, is home to the U.S. auto industry as well as a major global center of automotive research and manufacturing. The auto industry can potentially benefit from the identification of cost-effective options for counterbalancing the CO2 emissions from the use of their products. 
• The midwest is the heart of the U.S. biofuel industry, where most corn ethanol production is located, and is a major agricultural region with extensive rural land now used for many purposes (including suburbanization) but which could also have a significant potential for reforestation or other forms of terrestrial carbon uptake and storage. 
• The midwest has been struggling economically, as its traditional industries have both increased productivity (reducing the need for labor) and been adversely affected by outsourcing many aspects of production. New opportunities for value creating tied to the land itself could provide robust economic opportunities for the future. 
• Much of the region has dispersed settlement patterns and so is not particularly suitable for either extensive mass transit or vehicle electrification based on available and near-term technological capabilities. Therefore, its transportation systems will remain almost exclusively dependent on liquid fuels for the foreseeable future. 

The region is already experiencing climatic risks of the sort expected to worsen as global warming progresses. Most of the region's political leaders have opposed strong policies for GHG mitigation (opposition that is by and large bipartisan, though it may be expressed differently by members of different parties). However, this policy challenge may be related to the fact that many proposed solutions are seen as having an adverse economic impact on the region's interests, given its historical heavy industry and agricultural base and dependence on coal for power generation. Identifying new opportunities for carbon mitigation that work better with the region's resources and economic base may be more attractive politically than what has been previously proposed. 

Generalizing what biofuels do

Many people have thought of biofuel as the ideal way to replace petroleum fuels. Biofuels can be liquids, and in fact, "liquid fuel made from biomass" is the most common meaning of the term. Because the focus here is on liquid carbon, liquid forms are the biofuels of interest. Examples include ethanol and biodiesel.

Basic chemistry tells us that the amount of CO2 released when burning liquid fuels is essentially the same for a given amount of energy provided. However, the common view is that biofuels are inherently carbon neutral. That's because the CO2 released when the biofuel is burned is offset by the CO2 that was taken up from the atmosphere when the fuel's biomass feedstock was grown. Combine this fact with the fact that biofuels can be produced from home-grown biomass, and it's easy to see why biofuels have such enormous appeal as replacements for oil.

The LCA script

Lifecycle analysis (LCA) is a very popular form of environmental assessment. A good number of academics and others assert that it is the ideal way to examine greenhouse gas emissions impacts and so advocate LCA as a way to compute "carbon footprints."

This view has come to dominate energy policy discussions of ways to reduce GHG emissions from transportation fuels. In particular, nearly everyone involved in the issue says that biofuels should be evaluated according to their full lifecycle impacts. As the major UNEP report on Assessing Biofuels puts it, "Environmental and social impacts need to be assessed throughout the entire life-cycle."

However, biofuel LCA has become ever more complex and has resulted in models that are no longer even close to being scientifically verifiable. Therefore, no amount of new data that one puts into a lifecycle study can put an end to the disputes over LCA-based estimates of the net GHG impact of biofuels. This argument is made in the paper "Biofuels and Carbon Management" Climatic Change (2012), which then proposes a different approach to analysis.

Liquid fuels and carbon dioxide

A most troubling aspect of the global climate problem is the carbon dioxide (CO₂) emitted by petroleum consumption. Oil is still the world's largest source of energy, though it now runs second to coal as a direct source of anthropogenic CO₂ emissions. Oil is a liquid and is by far the main feedstock for liquid fuels, i.e., hydrocarbon energy carriers such as gasoline, diesel, jet fuel, bunker oil and so on.

Carbon dioxide

Combustion of any liquid hydrocarbon fuel directly releases an amount of CO₂ that varies only a little depending on the fuel. This is true for most carbon based liquids, not just strictly hydrocarbons. For example, burning ethanol directly releases only about 2% less CO₂ than gasoline for a given amount of energy provided.

Therefore, in terms of direct emissions, changing the form of the liquid fuel, e.g., from gasoline to ethanol or from diesel to biodiesel, makes no appreciable difference in the amount of CO₂ released to the atmosphere. 

Therefore, as long as society burns liquid fuels -- and we now consume enough of them to make oil the world's number one source of commercial energy -- we have what can be called a "liquid carbon" problem. I'll leave to others the tasks of thinking about how to replace liquid fuels, for example, with electric cars or hydrogen-powered vehicles, using energy carriers that don't contain carbon atoms. Meanwhile, society has a huge liquid carbon problem to solve. 

An unheeded warning on ethanol

As concerns about the adverse impacts of expanding biofuel use continue to mount, I can't help but note that a number of policy analysts raised red flags about the issue a decade ago, when proposals to mandate biofuel use began to get legs in Washington. Such was the case for a short position statement opposing an ethanol mandate that I co-wrote while on staff at the Environmental Defense Fund (EDF).

The 9/11 attacks in 2001 shocked U.S. public sentiment in many ways, including a re-awakened concern about energy security and the risks of dependence on foreign oil, as many put it. Policymakers suddenly became much more willing to seriously back petroleum alternatives. Biofuels had long enjoyed a basic level of support, including subsidies established following the 1970's oil crises. Ethanol advocates now saw an opportunity to boost biofuel production in a political climate that made policymakers from both parties happy to intervene in the market as a way to show the public that they were taking action on energy security.

Bills to mandate ethanol in gasoline were introduced early in 2002. The policy immediately found support, especially in the Senate where heartland votes easily overcame the skepticism of members from the left and right coasts.

A number of environmental organizations viewed biofuels as a crucial renewable alternative to petroleum-based gasoline. Although the net benefits of corn ethanol were always questioned, some green campaigners thought it had at least modest benefits. Just as importantly, they believed that mandating ethanol would build a market that would eventually shift away from corn to hoped-for cellulosic feedstocks that were considered much more beneficial.

Along with fellow EDF staffer Tim Searchinger, I was then quite skeptical of ethanol. The position statement we wrote opposing the ethanol mandate argued that its greenhouse gas reduction benefits were small at best while the expansion of corn growing that it would induce would be harmful to wildlife and water quality.

Needless to say, cautious voices like ours were drowned out by the rising chorus of those who were promoting biofuels for one reason or another, from the understandable self-interest of corn growers and processors to energy security hawks and green advocates of renewable energy.

Although other policy disagreements prevented an energy bill from passing in 2002, the ethanol mandate was one of the most widely supported provisions. It was re-introduced in successive Congresses, passing as part of the 2005 Energy Policy Act and then being greatly expanded by the 2007 Energy Independence and Security Act (EISA).

In retrospect, our reasons for skepticism were even better founded than we knew at the time, and the ethanol mandate has turned out to be even more of an environmental disaster than we imagined.

Biofuels and climate: a simple but troubling view

If biofuels benefit the climate, it's not when they're burned; those CO₂ emissions are the same as from the fossil fuels they replace. Any potential benefit is due to the CO₂ uptake when plants are grown. Society should maximize that uptake and, once carbon is absorbed, do everything possible to keep it from getting back into the air. This almost certainly means not burning biofuels. 

Automotive carbon-cutting bang-for-buck

Fuel efficiency is clearly the low-hanging fruit when it comes to reducing CO2 emissions from cars and trucks. But what if we need to reach higher on the technology tree to get on track to cutting carbon as much as eventually will be needed? 

Alternatively fueled vehicles (AFVs), meaning cars designed to run on something other than gasoline or diesel fuel made from petroleum, are commonly touted as "clean fuel vehicles," and green-leaning policymakers promote them as a key part of sustainable energy strategy. 

Although various AFVs have gone in and out (and in again) of favor over the years, some form of all-electric drive is often seen as a leading contender for the car of the future. In 1990, California issued a zero-emission-vehicle (ZEV) mandate to push battery electric vehicles (BEVs) and eventually hydrogen fuel cell vehicles (FCVs) into the market. Originally justified as the solution to smog-forming tailpipe pollution, ZEVs are now thought to be crucial for cutting carbon. Given the range limitations of BEVs, plug-in hybrid electric vehicles (PHEVs) that can both charge up with electricity and fill up on gasoline have been added to the portfolio as well. 

The Fuel Efficiency Horizon study, however, shows that the supply of low-hanging fruit is more ample than many people think. The adjoining chart compares the relative cost to the relative GHG reduction benefit for several competing technology options. 

The vertical axis gives the costs as a percentage increase over the price of a baseline vehicle, taken as a 2005 midsize car. The horizontal axis gives the percentage cut in GHG emissions relative to the baseline, counting emissions both downstream at the tailpipe and upstream at locations where fuels or electricity are produced. All of the options reflect projections of lower costs and improved performance attainable by 2035, drawing results from the MIT On the Road in 2035 report. The BEV, FCV and PHEV points assume modest reductions in upstream GHG emissions for electricity and hydrogen. No upstream GHG reduction or CO2 offset is assumed for the gasoline or diesel vehicles. 

The upshot? Efficiency improvement remains the least costly way to cut auto sector CO2 emissions for the foreseeable future. This fuel efficiency horizon involves only vehicles that still rely solely on gasoline or diesel, up to and including "grid-free" (non-plug-in) hybrid electric vehicles (shown as the "gasoline hybrid" point on the chart). These ongoing efficiency gains offer GHG reductions greater than those from the battery electric, hydrogen fuel cell and plug-in hybrid technologies at a lower cost (a cost that is far lower in comparison to BEVs). 

In short, an evolutionary technology pathway, highlighted as the shaded band in the lower portion of the chart, will enable quite a lot of progress over the next 25 years, and do so without the high costs, consumer acceptance concerns and fuel infrastructure barriers faced by the alternatives.  

Auto efficiency: how much is on the horizon?

Everyone appreciates how higher fuel efficiency is important for controlling oil use and greenhouse gas (GHG) emissions. Although efficiency can be given a big boost by making a vehicle all-electric, plug-in cars have limitations as well as high costs. And so a key question is this: how much can we improve the fuel economy of "grid-free" automobiles that still use only gasoline?  

Most technologies can progress quite a lot given sufficient time, but policymakers concerned about climate want to cut GHG emissions substantially by mid-century. Because it takes roughly 15 years to replace the on-road stock of cars and light trucks, the relevant question becomes that of how much more efficient new vehicles could be by 2035. 

An answer is provided in a recent report, A Fuel Efficiency Horizon for U.S. Automobiles. This study examines how far auto efficiency can be taken if it is pursued with determination, using technology and design options that offer a "revolution by evolution." 

Quite a lot of progress -- as much as a tripling of new fleet average fuel economy -- can be made through ongoing refinements to vehicles that still rely on internal combustion engines as their sole and prime mover. Costs are involved, but much less than the costs of electric and other alternatively fueled vehicles (AFVs), which face infrastructure barriers and other market challenges.  

Addressing biofuel GHG emissions in the context of a fossil-based carbon cap

What follows is the abstract of an in-depth discussion paper that reflects an early stage of my re-evaluation of lifecycle analysis methods for fuels policy. 

Renewable fuels have been promoted as a climate solution as well as for their energy security and domestic economic benefits. Analysts often assume that, other than process emissions, biofuels emit no net CO2 because their biogenic carbon was recently absorbed from the atmosphere. This "renewability shortcut" has shaped both public perception and public policy to date. Cap-and-trade policies follow GHG inventory conventions that use the shortcut and so fail to properly account for biofuel emissions. They also miss portions of the upstream GHG emissions from fossil-based transportation fuels, although most such emissions are trade related.

Lifecycle analysis (LCA), which attempts to account for all of the GHG impacts associated with fuel production, has been proposed as a means of regulating fuels for climate policy. LCA is used to qualify certain fuels for the U.S. federal renewable fuel standard (RFS) and also forms the basis of a low-carbon fuel standard (LCFS). However, as LCA system boundaries have expanded to address market effects such as induced land-use change, its application in policy has become controversial.

This paper examines these issues, quantifies GHG emissions missed by cap-and-trade policies as commonly proposed, and identifies ways to address biofuel emissions in the context of a carbon cap that covers major emitting sectors. Resource economics suggests that policy should be defined by annual basis accounting of carbon stocks and flows and other GHG fluxes rather than by LCA. This perspective suggests the use of a three-part approach: (1) correct specification of the transportation sector point of regulation with careful carbon accounting at the point of finished fuel distribution; (2) voluntary fuel and feedstock GHG accounting standards to track CO2 uptake and uncapped GHG emissions throughout the fuel supply chain; and (3) a land protection fund for purchasing international forest carbon offsets to mitigate leakage.

While an RFS can remain in place to drive volumes of specified fuels into the market, this approach avoids the need for either LCA requirements in the RFS or the added regulatory layer of an LCFS. Integrated into a cap-and-trade framework, this market-based approach would provide biofuel and feedstock production with a carbon price incentive tied to the cap, creating a more complete carbon management framework for the transportation fuels sector.

Citation and link: 

DeCicco, J.M. 2009. Addressing Biofuel GHG Emissions in the Context of a Fossil-Based Carbon Cap. Discussion Paper prepared for the Environmental Defense Fund. Ann Arbor: University of Michigan, School of  Natural Resources and Environment, October. http://hdl.handle.net/2027.42/76029