As Brazil ramps up sugarcane production, researchers foresee regional climate effects

March 7, 2013

Conversion of large swaths of Brazilian land for sugar plantations will help the country meet its needs for producing cane-derived ethanol, but it also could lead to important regional climate effects, according to a team of researchers from Arizona State University, Stanford University and the Carnegie Institution for Science.

The team found that anticipated conversion to sugarcane plantations could lead to a 1 degree Celsius decrease in temperature during the growing season, to be followed by a 1 degree Celsius increase after harvest. Download Full Image

“When averaged over the entire year, there appears to be little effect on temperature,” said Matei Georgescu, an assistant professor in ASU’s School of Geographical Sciences and Urban Planning, a senior sustainability scientist in the Global Institute of Sustainability, and lead author of the paper. “However, the temperature fluctuation between the peak of the growing season, when cooling occurs relative to the prior landscape, and crop harvest, when warming occurs compared to the previous landscape, of about 2 degrees Celsius (3.6 degrees Fahrenheit) is considerable.”

The researchers published their findings March 7 in the early online edition of Geophysical Research Letters. Co-authors with Georgescu are David Lobell of Stanford University; Christopher Field of the Carnegie Institution for Science (both located in Stanford, Calif.); and Alex Mahalov, the Wilhoit Foundation Dean’s Distinguished Professor in the School of Mathematical and Statistical Sciences, an academic unit of ASU's College of LIberal Arts and Sciences.

Countries worldwide are looking to cut their dependence on fossil fuels and bioethanol, and other biofuels are attractive alternatives. In Brazil, the second-largest global producer and consumer of bioethanol, this has led to a boom in sugarcane production.

Based on new laws and trade agreements, Brazil’s production of sugarcane-derived ethanol is expected to increase tenfold over the next decade, with considerable land being converted for growing sugarcane. Much of this expansion is expected to come at a loss of some of the country's native cerrado lands (i.e., tropical savannas of Brazil).

Biofuels are attractive because they reduce the amount of carbon pumped into the atmosphere and mitigate global climate change, but for Brazil the shifting agricultural activity could have direct consequences on its climate by changing the landscape’s physical properties.

The researchers used multi-year regional climate model simulations to calculate the potential for local changes in temperature and precipitation patterns. Based largely on sugarcane having a higher albedo (reflectivity) compared to the existing vegetation, and the fact that the crop will undergo an annual harvest while the savanna does not, the researchers found that the shift to sugar plantations will lead to a strong seasonal temperature fluctuation.

They also found that the sugarcane harvest should lead to a net annual drop in the transfer of water from the land to the atmosphere, referred to as evapotranspiration (ET).  

“When harvest occurs, the plant’s ability to transfer water from its extensive root system to the atmosphere is reduced,” said Georgescu. “As the crop matures during the growing season, ET is once again brought back to levels prior to sugarcane conversion. Overall, we find the annually averaged ET reduction is about 0.3 millimeters per day.”

The authors suggest that such conditions could cause a reduction in regional precipitation, though no such decrease was found to be statistically significant in the modeling study.

“We do notice a decrease in evapotranspiration and we are confident in these impacts,” Georgescu explained. “But there is much more uncertainty in regards to precipitation and more work is required in this area.”

The School of Geographical Sciences and Urban Planning is an academic unit in ASU's College of Liberal Arts and Sciences.

Associate Director, Media Relations & Strategic Communications


ASU researchers showcase energy technologies at Innovation Summit

March 7, 2013

The Department of Energy’s fourth annual ARPA-E Innovation Summit showcased a wide array of ASU energy technologies at the Gaylord Convention Center in Washington D.C. on Feb. 25-27. Technologies ranged from cyanobacterial biofuels to carbon capture to metal air battery storage.

ARPA-E is the Advanced Research Projects Agency-Energy housed within the U.S. Department of Energy, seeking to streamline the awards process in fostering and cultivating cutting-edge, high-impact energy research that is too early for private sector investment. ARPA-E awards are highly competitive, awarded to transformative projects with the high potential of radically improving U.S. energy security, economic prosperity and environmental well-being. Willem Vermaas Download Full Image

“ASU’s participation in the ARPA-E Innovation Summit included faculty and students who presented their innovative energy-related research projects,” said Sethuraman “Panch” Panchanathan, senior vice president for ASU’s Office of Knowledge Enterprise Development. “Our ARPA-E research projects are aligned with the use-inspired focus at ASU and the advancement of entrepreneurship activities, resulting in economic development, as well as providing solutions to global energy challenges.”

Cyanobacteria as biofuel

Researchers at ASU are engineering Synechocystis, a specific type of photosynthetic cyanobacteria that has been modified to efficiently produce and excrete fatty acids, which can be used as a precursor for biofuels. This type of bacteria is already quite good at converting carbon dioxide and solar energy into fatty acids that are incorporated into lipids. Researchers at ASU have made modifications to the bacteria, which allow it to continuously convert sunlight and carbon dioxide into a desired fatty acid, laurate and excrete it. Rather than using solar energy solely for cell growth, this process maximizes the sunlight-to-fuel conversion process.

ASU’s research is uniquely emphasizing increased production of fatty acids when most biofuels research aims to increase cellular biomass. This process provides great potential in future transportation technology because the project has identified a way to convert harvested lauric acid into alkanes and their isomers that have specifications similar to existing transportation fuels and that can be directly incorporated into the existing infrastructure. Additionally, the process creates a carbon-neutral system that recycles carbon dioxide from fuel combustion back into a usable fuel without requiring extensive farming practices and arable land associated with many current biofuel crops.

The project also addresses climate issues and benefits the environment. “The challenge for society is to reduce CO2 emissions to a point where they don’t go through the roof. There’s only so much oil and natural gas you can extract from the ground, and there’s only so much CO2 you can put into the atmosphere,” says ASU researcher Wim Vermaas, who is a professor in the School of Life Sciences, in the College of Liberal Arts and Sciences.

Electrochemical carbon capture technology

ASU researchers from the Department of Chemistry and Biochemistry; the School for Engineering for Matter, Transport and Energy; and ASU LightWorks have developed an approach to carbon dioxide capture technology through an energy-efficient electrochemical process. This new technique has the potential to vastly change the way energy is produced and consumed, and it can be used on existing power plants, separating the carbon dioxide from other emissions released from the flue, with the possibility of significantly reducing costs and energy requirements.

Carbon capture technology has gained attention in recent years in addressing carbon neutrality. Former Energy Secretary Steven Chu initiated carbon capture and storage (CCS) initiatives with the hope to fund technologies that efficiently reduce carbon emissions “by harnessing the power of science and technology.”

The CCS initiative “will not only help fight climate change, it will create new jobs and position the United States as a leader in carbon capture and storage technologies for years to come,” says Secretary Chu.

Spinout research in air battery storage

Fluidic Energy, a spinout from ASU directed by Cody Friesen, is developing high-power, low-cost, rechargeable Zinc-air batteries for renewable energy storage. Traditionally, Zinc-air batteries are found in small, non-rechargeable devices like hearing aids, delivering low power levels over extended periods of time and have thus not been useful for applications requiring periodic increases in power. Fluidic’s goal is to combine the low-cost, high energy, long running Zinc-air battery with new chemistry approaches that allow high efficiency, high power, quick responding battery technologies. 

This research has the potential to offer transformative, high-impact solutions for renewable energy storage issues in the grid. Electricity currently accounts for 40 percent of U.S. carbon emissions and could substantially decrease with the grid resiliency provided by this new technology.

Friesen says that “ARPA-E has enabled us to go after technologies and solutions that we would not have otherwise gone after because of the degree to which those solutions and those ideas were off the beaten path from our core technology. That is massive impact.”

LightWorks as a strategic umbrella

ASU LightWorks is a far-reaching initiative that provides a strategic approach to leveraging ASU’s unique strengths in renewable energy research in areas of technology, energy and society, policy, social engagement and outreach.

“LightWorks looks at a problem like transportation fuel, surveys the expertise and infrastructure at ASU and creates collaborative groups both within and outside the university to focus on the problem,” says director Gary Dirks. “We emphasize working with other university groups, government agencies, NGOs and private industry to put the right minds and resources together to create meaningful solutions to real-world problems our energy system faces in the coming decades.”

ASU already has a massive renewable energy portfolio that continues to grow and a network of accomplished researchers who continue to provide innovative solutions to current energy problems.

"ASU is among the top universities in the country when it comes to energy technology," says Dirks. "Our algae biomass and solar facilities are some of the best in the country and we are on the leading edge of other areas such as policy innovation and socioeconomic implications of energy systems change. We have also had success in spinning out companies in many areas of energy research including battery storage, wind forecasting and algae.”

LightWorks also had a booth at the ARPA-E Innovation Summit, displaying the wide range of energy technologies and research happening at ASU. Aside from the ARPA-E awardees, some of the projects showcased included the ATP3 national algae testbed at the Polytechnic campus, AzCATI algae facilities, QESST solar research, LightSpeed Solutions in sunlight-to-fuels, the new Energy Social Sciences Initiative, and Solar Decathlon.

Written by Sydney Lines, ASU LightWorks