Friday, August 27, 2010

Study shows deepwater oil plume in Gulf degraded by microbes

In the aftermath of the explosion of BP’s Deepwater Horizon drilling rig in the Gulf of Mexico, a dispersed oil plume was formed at a depth between 3,600 and 4,000 feet and extending some 10 miles out from the wellhead. An intensive study by scientists with the Lawrence Berkeley National Laboratory (Berkeley Lab) found that microbial activity, spearheaded by a new and unclassified species, degrades oil much faster than anticipated. This degradation appears to take place without a significant level of oxygen depletion.

“Our findings show that the influx of oil profoundly altered the microbial community by significantly stimulating deep-sea psychrophilic (cold temperature) gamma-proteobacteria that are closely related to known petroleum-degrading microbes,” says Terry Hazen, a microbial ecologist with Berkeley Lab’s Earth Sciences Division and principal investigator with the Energy Biosciences Institute, who led this study. “This enrichment of psychrophilic petroleum degraders with their rapid oil biodegradation rates appears to be one of the major mechanisms behind the rapid decline of the deepwater dispersed oil plume that has been observed.”

The uncontrolled oil blowout in the Gulf of Mexico from BP’s deepwater well was the deepest and one of the largest oil leaks in history. The extreme depths in the water column and the magnitude of this event posed a great many questions. In addition, to prevent large amounts of the highly flammable Gulf light crude from reaching the surface, BP deployed an unprecedented quantity of the commercial oil dispersant COREXIT 9500 at the wellhead, creating a plume of micron-sized petroleum particles. Although the environmental effects of COREXIT have been studied in surface water applications for more than a decade, its potential impact and effectiveness in the deep waters of the Gulf marine ecosystem were unknown.

Analysis by Hazen and his colleagues of microbial genes in the dispersed oil plume revealed a variety of hydrocarbon-degraders, some of which were strongly correlated with the concentration changes of various oil contaminants. Analysis of changes in the oil composition as the plume extended from the wellhead pointed to faster than expected biodegradation rates with the half-life of alkanes ranging from 1.2 to 6.1 days.

“Our findings, which provide the first data ever of microbial activity from a deepwater dispersed oil plume, suggest that a great potential for intrinsic bioremediation of oil plumes exists in the deep-sea,” Hazen says. “These findings also show that psychrophilic oil-degrading microbial populations and their associated microbial communities play a significant role in controlling the ultimate fates and consequences of deep-sea oil plumes in the Gulf of Mexico.”

The results of this research were reported in the journal Science (August 26, 2010 on-line) in a paper titled “Deep-sea oil plume enriches Indigenous oil-degrading bacteria.” Co-authoring the paper with Hazen were Eric Dubinsky, Todd DeSantis, Gary Andersen, Yvette Piceno, Navjeet Singh, Janet Jansson, Alexander Probst, Sharon Borglin, Julian Fortney, William Stringfellow, Markus Bill, Mark Conrad, Lauren Tom, Krystle Chavarria, Thana Alusi, Regina Lamendella, Dominique Joyner, Chelsea Spier, Jacob Baelum, Manfred Auer, Marcin Zemla, Romy Chakraborty, Eric Sonnenthal, Patrik D'haeseleer, Hoi-Ying Holman, Shariff Osman, Zhenmei Lu, Joy Van Nostrand, Ye Deng, Jizhong Zhou and Olivia Mason.

Hazen and his colleagues began their study on May 25, 2010. At that time, the deep reaches of the Gulf of Mexico were a relatively unexplored microbial habitat, where temperatures hover around 5 degrees Celsius, the pressure is enormous, and there is normally little carbon present.

“We deployed on two ships to determine the physical, chemical and microbiological properties of the deepwater oil plume,” Hazen says. “The oil escaping from the damaged wellhead represented an enormous carbon input to the water column ecosystem and while we suspected that hydrocarbon components in the oil could potentially serve as a carbon substrate for deep-sea microbes, scientific data was needed for informed decisions.”

Hazen, who has studied numerous oil-spill sites in the past, is the leader of the Ecology Department and Center for Environmental Biotechnology at Berkeley Lab’s Earth Sciences Division. He conducted this research under an existing grant he holds with the Energy Biosciences Institute (EBI) to study microbial enhanced hydrocarbon recovery. EBI is a partnership led by the University of California (UC) Berkeley and including Berkeley Lab and the University of Illinois that is funded by a $500 million, 10-year grant from BP.

Results in the Science paper are based on the analysis of more than 200 samples collected from 17 deepwater sites between May 25 and June 2, 2010. Sample analysis was boosted by the use of the latest edition of the award-winning Berkeley Lab PhyloChip – a unique credit card-sized DNA-based microarray that can be used to quickly, accurately and comprehensively detect the presence of up to 50,000 different species of bacteria and archaea in a single sample from any environmental source, without the need of culturing. Use of the Phylochip enabled Hazen and his colleagues to determine that the dominant microbe in the oil plume is a new species, closely related to members of Oceanospirillales family, particularly Oleispirea antarctica and Oceaniserpentilla haliotis.

Hazen and his colleagues attribute the faster than expected rates of oil biodegradation at the 5 degrees Celsius temperature in part to the nature of Gulf light crude, which contains a large volatile component that is more biodegradable. The use of the COREXIT dispersant may have also accelerated biodegradation because of the small size of the oil particles and the low overall concentrations of oil in the plume. In addition, frequent episodic oil leaks from natural seeps in the Gulf seabed may have led to adaptations over long periods of time by the deep-sea microbial community that speed up hydrocarbon degradation rates.

One of the concerns raised about microbial degradation of the oil in a deepwater plume is that the microbes would also be consuming large portions of oxygen in the plume, creating so-called “dead-zones” in the water column where life cannot be sustained. In their study, the Berkeley Lab researchers found that oxygen saturation outside the plume was 67-percent while within the plume it was 59-percent.

“The low concentrations of iron in seawater may have prevented oxygen concentrations dropping more precipitously from biodegradation demand on the petroleum, since many hydrocarbon-degrading enzymes have iron as a component,” Hazen says. “There’s not enough iron to form more of these enzymes, which would degrade the carbon faster but also consume more oxygen.”

Source : Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California.

Wednesday, August 4, 2010

New Study Sheds Light on U.S. Wind Power Market

The U.S. was one of the fastest-growing wind power markets in the world in 2009, second only to China, according to a report released today by the U.S. Department of Energy and prepared by Lawrence Berkeley National Laboratory.

Wind power additions in the United States set a new record in 2009, with 10 gigawatts of new capacity installed, representing a $21 billion investment. “At this pace, wind power is on a path to becoming a significant contributor to the U.S. power mix,” says co-author Ryan Wiser, a scientist in Berkeley Lab’s Environmental Energy Technologies Division (EETD). “Wind power projects accounted for 39 percent of all new electric generating capacity added in the U.S. in 2009, and wind energy is now able to deliver 2.5 percent of the nation’s electricity supply.”

The 2009 edition of the “Wind Technologies Market Report” provides a comprehensive overview of developments in the rapidly evolving U.S. wind power market. The need for an annual report of this type has grown as the wind power industry has entered an era of unprecedented expansion, both globally and in the United States.

At the same time, as the report documents, the past year has been one of upheaval. The global financial crisis and lower wholesale electricity prices have negatively impacted the near-term growth prospects for the wind power industry, while new federal policies are pushing the industry towards continued aggressive expansion.

“With the market evolving at such a rapid pace, keeping up with the latest developments has become increasingly difficult,” says co-author Mark Bolinger of EETD. “Yet, the need for timely, objective information on the industry and its progress has never been greater…this report seeks to fill this need.”

The report analyzes trends in wind power capacity growth, industry and manufacturing trends, turbine size, turbine prices, installed project costs, project performance, wind power prices, and how wind prices compare to the price of conventional generation. It also describes trends among developers, project owners, and wind power purchasers, and discusses financing issues. Finally, the report examines other factors impacting the domestic wind power market, including grid integration, transmission issues, and policy drivers. It concludes with a preview of possible near-term market developments.

For the first time, the report presents estimates of the proportion of U.S. wind turbine equipment costs that have derived from imports from other countries, finding that a growing percentage of equipment is being manufactured domestically. “The overall fraction of wind turbine equipment manufactured domestically grew from 50 percent in 2008 to roughly 60 percent in 2009,” notes Wiser.

Some of the key findings from the just-released 2009 edition include:

• The U.S. is the second-fastest-growing wind market worldwide. After leading the world for the past four years, the U.S. lost its top-market status in 2009, being overtaken by China as the country with the fastest pace of new wind power additions. Nonetheless, despite earlier grim predictions due to the financial crisis, the U.S. market continued to expand in 2009 and shattered its 2008 record for new wind power additions.
• Growth is distributed across much of the U.S. Texas led the nation with 2,292 MW of new wind power capacity, but 28 states saw new wind power plants constructed within their borders in 2009. Wind power now provides more than 10 percent of in-state electricity generation in four states: Iowa (20 percent), South Dakota (13 percent), North Dakota (12 percent), and Minnesota (11 percent). Offshore wind power project and policy developments also accelerated in 2009.
• Market growth is spurring manufacturing investments in the U.S. Wind turbine manufacturers with modern wind turbines installed in the United States now hail from not just the United States, Europe, and Japan, but also from India and, for the first time in 2009, China. Seven of the 10 wind turbine manufacturers with the largest share of the U.S. market in 2009 now have one or more manufacturing facilities operating in the United States, and two of the remaining three have announced plans to open facilities in the future.
• A growing percentage of the equipment used in U.S. wind projects is domestically manufactured. Trade data show that the United States remained a large importer of wind turbine equipment in 2009, with $4.2 billion of imports, up from $2.5 billion in 2006, but down from $4.6 billion in 2007 and $5.4 billion in 2008. Wind power capacity growth has outpaced growth in imports in recent years, and a growing amount of the equipment used in wind power projects is therefore being sourced domestically as domestic and foreign companies seek to minimize transportation costs and currency risks by establishing local manufacturing capabilities.
• Wind power project costs continued to increase into 2009, but reductions may be on the horizon. Installed wind power project costs in 2009 averaged $2,120/kW, up by 9 percent over the 2008 figure. There are expectations that costs will drop in the near future as past cost pressures ease and work their way through to average installed costs.
• Wind project performance has improved over time but dropped off in 2009. The longer-term improvement in project performance has been driven in part by taller towers and larger rotors. The drop in 2009 is, in part, attributable to a relatively poor wind resource year in many parts of the country along with increasing amounts of wind power curtailment—particularly in Texas, where 17 percent of all potential wind energy generation was curtailed in 2009 because of transmission inadequacy.
• Rising wind power prices and sharply lower wholesale prices make the near-term economics of wind energy more challenging. Although some of the cost pressures facing the industry in recent years have eased, 2009 was another year of rising average wind power prices. The average 2009 sales price from projects built in 2009 was roughly $61/MWh.
• Looking ahead, expectations are for a slower year in 2010. Lower expectations stem from a combination of the financial crisis, lower wholesale electricity prices, and lower demand for renewable energy. Projections among industry analysts range from 5,500 MW to 8,000 MW of wind power capacity likely to be installed in the United States in 2010, a drop of 20 to 45 percent compared to the nearly 10,000 MW installed in 2009. After a slower 2010, most predictions show market resurgence in 2011 and 2012, as programs funded by the American Recovery and Reinvestment Act mature and as financing constraints ease. Beyond 2012, however, the picture is considerably less certain, because of the scheduled expiration of a number of federal policies at the end of that year.

Berkeley Lab’s contributions to this report were funded by the Wind & Water Power Program, Office of Energy Efficiency and Renewable Energy of the U.S. Department of Energy.

Lawrence Berkeley National Laboratory provides solutions to the world’s most urgent scientific challenges including clean energy, climate change, human health, novel materials, and a better understanding of matter and force in the universe. It is a world leader in improving our lives and knowledge of the world around us through innovative science, advanced computing, and technology that makes a difference. Berkeley Lab is a U.S. Department of Energy (DOE) national laboratory managed by the University of California for the DOE Office of Science. 


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