Union of Concerned Scientists warns for pollution from liquid coal fuels; new biofuels way forward

Heightened concern about oil dependence is generating growing support for alternative transportation fuels, but some fuels, like liquid coal and gasoline from tar sands would emit significantly more global warming pollution than gasoline or diesel, according to a new report issued today by the Union of Concerned Scientists (UCS). In Biofuels: An Important Part of a Low-Carbon Diet, the UCS offers an overview of the lifecycle emissions of different alternative fuels, and two scenarios for their future role in America's transportation fuel mix. It also stresses the importance of comprehensive lifecycle analyses (LCAs) to take into account the entire emissions profile of alternative fuels.

Transportation is responsible for two-thirds of US oil consumption and nearly 40 percent of the country's global warming pollution on a life cycle basis. To dramatically cut emissions from this sector, a comprehensive solution must include improved vehicle fuel efficiency, smart growth policies that reduce vehicle miles traveled, and clean fuel alternatives.

Liquid coal, for example, can release 80 percent more global warming pollution than gasoline, the report found. Corn ethanol, conversely, could be either more polluting or less than gasoline, depending on how the corn is grown and the ethanol is produced. On average, corn ethanol can reduce emissions about 20 percent, though there is uncertainty due to differing land use practices. The cleanest alternative, cellulosic ethanol from grasses or wood chips, could reduce emissions by more than 85 percent (graph, click to enlarge). (Note that the study did not look at first generation biofuels made from tropical crops like sugarcane or sweet sorghum which reduce emissions far more than corn ethanol; for sugarcane ethanol, the reduction is as large as that of cellulosic biofuels, earlier post.)

Biofuels can quickly become a staple of a low-carbon fuel diet because they integrate well with the existing fuel distribution infrastructure and offer potentially abundant domestic supplies with significant opportunities for growth, the report says. But not all biofuels are the same. There is a wide range in the estimated heat-trapping emissions and other environmental impacts from each biofuel over its life cycle (i.e., from farm to finished fuel to use in the vehicle), depending on the feedstock, production process, and model inputs and assumptions. There are also concerns about emissions and impacts from land conversion and land use associated with biofuel production.

New rules are being developed that will require fuel providers to account for and reduce the heat-trapping emissions associated with the production and use of transportation fuels. For example, both the U.S. Congress and Environmental Protection Agency (EPA) are considering strategies to promote low-carbon and renewable transportation fuels (including biofuels). California, the nation's largest market for transportation fuel, is developing a Low Carbon Fuel Standard that will require fuel providers to demonstrate reductions in global warming pollution per unit of energy delivered, regardless of fuel source. More state, regional, and federal rules will undoubtedly follow, the UCS writes.

The purposes of the report are two-fold:

1. To ensure that we “count carbs” accurately, by explaining why we need a comprehensive accounting system for carbon emissions—one that measures global warming emissions over a transportation fuel's entire life cycle. An effective accounting system will not only need to be robust enough to encompass the fuel life cycle, but also address uncertainties and allow for changes over time as better assessment tools and methods become available.
2. To “make carbs count” by describing performance-based policies that will reward low-carbon transportation fuels for their performance and help them compete against highly polluting fuels such as liquid coal (gasoline or diesel made from coal). For example, low-carbon fuel standards require a reduction in the average amount of global warming pollution per gallon of fuel.

A market for low-carbon fuels can produce a rare convergence of business, agricultural, and environmental interests that, if pursued wisely, could represent a “win-win-win” opportunity. But the promise of a lower-carbon transportation future can only be realized through federal and state policies that “count carbs and make carbs count.”

Two scenarios
The report evaluated two scenarios for alternative fuels, one carbon-intensive — meaning that it would produce significantly more global warming pollution than burning gasoline - and the other low-carbon — meaning that it would produce significantly less. The analysis assumed that alternative fuels will replace 37 billion gallons of gasoline, about 20 percent of the fuel UCS projects Americans will consume in 2030.

In both scenarios, conventional biofuels would meet 25 percent of the demand for alternative fuels. In the carbon-intensive scenario, the remaining demand would be met by liquid coal. The carbon-intensive scenario would increase emissions by 233 million metric tons — equivalent to adding about 34 million cars to the road, the number of new cars and light trucks currently sold nationally over a two-year period. By contrast, the low-carbon scenario relies on advanced biofuels to meet 75 percent of the demand. That would cut global warming pollution by 244 million metric tons, akin to taking 35 million of today’s cars off the road:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: biodiesel :: cellulosic :: tar sands :: liquid coal :: lifecycle analysis :: emissions :: climate change ::
The report calls for a national low-carbon fuel standard that accounts for alternative fuels’ global warming emissions over their entire life cycle—from till to tailpipe — and requires them to emit less pollution than today’s petroleum-based fuels.

At the tailpipe, gasoline, liquid coal and biofuels release about the same amount of global warming pollution. But there are dramatic differences in the amount of pollution emitted by extracting a raw feedstock and refining it into a finished fuel. Biofuels can have an advantage over liquid coal and gasoline because plants capture carbon dioxide, the most common global warming gas, as they grow. But producing biofuels will generate emissions, which at the farm will vary depending on tilling practices, fertilizer use, previous land use, and the fossil fuels used to power farm equipment. At the ethanol plant, emissions will depend on the efficiency of the manufacturing process and the fuel used to power the facility. All of these factors must be considered in a full life cycle analysis.

Life cycle analysis for alternative fuels could help farmers and the biofuels industry, according to Gregg Heide of the Iowa Farmers Union.

Farmers want to help get the country off of oil. Give us some guidelines, tell us where to cut pollution, and we can do it. The coal lobby is active everywhere, even here in Iowa. It would be counterproductive if dirty fuels like liquid coal started muscling out biofuels in the alternative fuels market. - Gregg Heide, Iowa Farmers Union

Congress is now considering an energy bill that includes a renewable fuel standard giving the Environmental Protection Agency the authority to develop life cycle analysis guidelines. To date, the federal government has been promoting both cleaner and dirtier fuels. For instance, Congress has approved funding for research into next-generation ultra-clean biofuels, but it also is subsidizing research into liquid coal processing technology.

Government policies and high oil prices have whetted our growing appetite for all alternative fuels, good and bad alike. With the wrong policy, liquid coal could displace cleaner alternatives. Biofuels can be a staple of our low carbon fuel diet, but only if policies are in place that ‘count carbs’ and ‘make carbs count.’ - Eli Hopson, Washington representative for Clean Vehicles at UCS

At least one state is addressing the problem. In January, California Gov. Arnold Schwarzenegger issued an executive order calling for establishing a state low-carbon fuel standard. The California Air Resources Board is currently developing regulations that would require manufacturers of transportation fuel sold in the state to reduce per gallon emissions of global warming pollution by at least 10 percent. Arizona, Minnesota, New Mexico, Oregon and Washington State are considering similar policies.

Counting carbs
To fully assess the global warming impact of transportation fuels, we must measure their full life cycle emissions per unit of energy delivered. This poses an analytical challenge for a number of reasons. For example, plants capture carbon dioxide (CO2, a potent heat-trapping gas) from the atmosphere during photosynthesis, but the impact of this carbon capture on biofuel emissions varies by feedstock. The global warming pollution produced by farming varies depending on the farming equipment, fertilizers, tillage practices, and perhaps most important, whether forests and grassland are converted into cropland. Even the refining process used to convert biomass into biofuels produces varying amounts of heat-trapping emissions.

Emissions may vary depending on the feedstock and refining process. Liquid coal, for example, can increase emissions more than 80 percent compared with gasoline. Gasoline produced from tar sands can increase emissions about 14 percent. Corn ethanol, depending on how it is processed, can produce higher emissions than gasoline or cut emissions more than 50 percent. Cellulosic ethanol, which is made from woody plants, may be able to reduce emissions more than 85 percent.

Life cycle analysis tools such as the U.S. Department of Energy's Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model have been critical in building understanding of the full impact of transportation fuels. But there is currently no scientific consensus on a single analytical approach, particularly for biofuels. Key areas of debate include the impact of land use changes, fertilizer use and emissions, coproducts, process emissions, and uncertainties or poor data.

While life cycle models typically estimate that today's average corn ethanol cuts global warming pollution about 20 percent compared with gasoline, some researchers estimate that it may actually increase global warming pollution. Similarly, biodiesel is generally credited with a 50 percent reduction in global warming pollution, but there is also research indicating that it may increase emissions as well. In addition, biofuel production could exacerbate deforestation, generating more global warming pollution and a host of concerns about the industry's sustainability.

The key to improving our understanding and quantification of life cycle emissions is to hold transportation fuel providers responsible for their global warming pollution. Our current system provides no incentive for fuel providers to accurately measure or minimize their carbon emissions. In contrast, a system that requires providers to account for their emissions would spur increased research into life cycle analysis and provide a public process for evaluating the benefits and limitations of different analytical methods. By developing emissions standards that are periodically updated using the best data available, the market can steer fuel production toward lower-carbon pathways.

Making carbs count
Without a framework in place to lower the carbon intensity of our transportation fuels, we risk losing a precious opportunity to cut our global warming pollution substantially. We therefore need smart fuel policies such as California's Low Carbon Fuel Standard, which is slated to take effect as early as 2010. This standard does not “pick winners” by focusing on specific fuels, but instead relies on performance criteria that require each gallon of fuel (on an energy-equivalent basis) to meet a standard for global warming pollution that becomes more strict over time. The standard encompasses the fuel's entire life cycle, promoting carbon reduction along every link in the fuel supply chain.

Low-carbon fuel standards would also create market certainty for cleaner fuels and complement existing vehicle standards by ensuring the fuel industry does its part—along with automakers and consumers—to reduce transportation-related emissions. Other states considering such regulations include Arizona, Minnesota, New Mexico, Oregon, and Washington.

At the national level, efforts are under way to incorporate heat-trapping emissions requirements into the current Renewable Fuel Standard, and several bills have been introduced in Congress that would establish a separate low-carbon fuel standard. The Bush administration is also preparing rules for reducing gasoline use that would include a low-carbon fuel component.

References:
Patrician Monahan, "Biofuels: An Important Part of a Low-Carbon Diet - An Important Part of a Low-Carbon Diet", - November 13, 2007.

Union of Concerned Scientists [press release]: When Carbon Counts, Biofuels Beat Liquid Coal - New Report Details Importance of Life Cycle Analysis for Alternative Fuels - November 13, 2007.

Union of Concerned Scientists: Smart Bioenergy - dedicated webpage on the UCS's take on this type of renewable energy.