Searching for the right alternative fuels

Image: Alan Taub_gm_alt_FuelsPanel.jpg

At an SAE 2011 World Congress panel on alternative fuels, Alan Taub, Vice President of Global Research for General Motors, discussed the challenges of supporting a growing worldwide fleet of cars

“All of us would agree we must address petroleum dependency. Most would agree that there is an environmental as well as economic price to that dependency,” stated Patrick Davis, Program Manager, Vehicle Technologies, the U. S. Department of Energy, as he opened the SAE 2011 World Congress panel, "Charging Forward on Petroleum Alternatives."

Another participant on the April 13 panel, General Motors Vice President for Global Research and Development Alan Taub, said: “The reason we are facing this challenge over fuels is because [the automotive] industry has been so successful.” He noted that a growing percentage of the world’s population can now afford a vehicle, and he presented data that projects a worldwide installed park of cars growing to 1.4 billion over today’s approximately 1 billion.

This is good news for automotive manufacturers, but the question now is whether the existing world infrastructure can support 1.4 billion active vehicles, he said. “We are reaching a tipping point where those sustainability factors are beginning to make the personal mobility experience less desirable.”

GM views alternative fuels holistically, categorizing liquid fuels and CNG; electricity; and hydrogen as the three main energy carrier types. While GM is willing to invest simultaneously in vehicles fueled by any of these energy sources, Taub went on to explain that it was not realistic in his view to deliver powertrains to an expanded number of individual energy sources such as oil, biomass, natural gas, coal, solar, wind, or even nuclear. In his view, energy from these major sources needs to be converted into one of the "big three" energy carriers to contain investment risk. GM is also embracing ethanol in the form of flex-fuel vehicles, which makes up a substantial portion of its fleet.

Nonpetroleum liquid fuels

One replacement for petroleum that seems simple enough is bio-derived fuels, such as ethanol. Given the issues with ethanol derived from food sources such as corn, including replacement of food crops and low energy-return-on-investment (EROI) of somewhere around 1, cellulosic sources of biofuel have long been sought.

“Our technology is ready, there is a well developed commercial pathway for full-scale production, and it is competitive with oil at $70 per barrel today,” said Bill Brady, Chief Executive Officer of the Mascoma Corp., developer of biofuels. The company uses something called Consolidated BioProcessing, with working plants in Kinross, MI, and Alberta, Canada, using hardwood as the feedstock.

Brady showed data that projected the process being competitive with oil at $55 per barrel by 2015. However, he warned, ramp-up from a working-scale plant such as the Kinross facility to plants that can produce meaningful, industrial-scale production runs the risk of entering the "valley of death," since they are too big for venture capital funding but not proven enough for either private equity or bank funding.

“Clear market signals are needed to raise money and attract partners for projects such as this,” Brady explained. They need to have certainty around tax policy and mandates such as the new set of renewable fuel standards that require 36 billion gal (136 billion L) per year of renewable fuel, including 16 billion gal (61 billion L) from cellulosic biofuels.

“The problem is that there is not enough infrastructure on the road, such as flex-fuel vehicles and blender pumps to support that mandate,” said Brady.

An even simpler approach in this arena, from the vehicle perspective, is use of so-called drop-in biofuels such as those developed by Rentech. Panelist Harold Wright, Senior Vice President and Chief Technology Officer for the company, said it has demonstrated both jet fuel and diesel that can be used by today without engines modifications—as is required today in flex-fuel vehicles.

He pointed to three major factors that need to be addressed to get biofuels to market faster. First is to reduce the price of feedstock. This means developing nonfood crops with high energy content. It also means reducing the travel time needed to get feedstock from fields to plant—a significant cost factor not often discussed. Second is designing and building biofuel plants that are smaller and more efficient, which to a degree solves the transport problem while reducing the capital needed and reducing investment risk. Third is continuing to develop partnerships with large commercial companies to help validate biofuels.

Beyond biofuels

Are biofuels the answer to replace petroleum? “The biomass resource will be finite, and there will be competition,” DOE's Davis said.

André Boehman, Professor of Fuel Science and Materials Science and Engineering at Pennsylvania State University, discussed some technologies that might expand biofuels beyond bio-derived sources. He emphasized that efficiency of conversion needs to be the key driver behind any selection.

Additional viable paths include algal biofuels and liquification from natural gas and coal, as well as DME from biomass. The most interesting might be fuels direct form solar, which Boehman described as getting little press attention but being able, potentially, to solve many of the issues coincident with fuels from plant sources.

David Friedman, Deputy Director Clean Vehicles for the Union of Concerned Scientists, was thinking in an entirely different way than his colleagues on the Petroleum Alternatives panel.

“The best alternative fuel is to use less,” he said.

With current mandates for renewable sources, as well as new CAFE mandates that phase in through 2016, gasoline demand will decrease through 2030, Friedman said. Even by then, he does not see biofuels as a substantial portion of the mix, with electric vehicles comprising an even smaller portion of the vehicle fleet.

“People are surprised by my projections for EVs, but beyond 2030 is when we will really start replacing oil with alternatives.”

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