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[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Thordon Bearings Retrofitting Ocean-Going Vessels With Seawater-Lubricated Propeller Shaft Bearings To Reduce Stern-Tube Oil Pollution; Annual Leaks Estimated at About 2x Exxon Valdez Spill
October 29, 2009
by Jeff Curtis and Jack Rosebro
| Cross-section of COMPAC seawater-lubricated stern tube bearing system for ocean-going vessels. Source: Thordon Bearings Click to enlarge. |
At last week’s Ocean Innovation 2009 conference in Victoria, British Columbia, Craig Carter, Director of Marketing and Customer Service at Thordon Bearings detailed the company’s progress in the retrofitting of large ocean-going vessels with seawater-lubricated propeller shaft bearings to reduce waterborne pollution.
At present, most commercial ocean-going ships use a propeller shaft that is supported by oil-lubricated bearings in the ship’s stern tube. Although the stern tube is typically fitted with forward and aft shaft seals, the seals are designed to expel contaminants by leaking aft into the sea or forward into the bilge. Aft seals are also commonly damaged by fishing net or rope that becomes entangled on the propeller shaft.
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Study Finds Water Use for Switchgrass Ethanol Production Approximately the Same as for Gasoline
August 23, 2009
| Consumptive freshwater use for ethanol and petroleum gasoline production. Data: Wu, ANL/ESD/09-1. Click to enlarge. |
In the US, producing one gallon of ethanol from switchgrass consumes approximately the same net amount of water as does producing a gallon of gasoline from conventional crude or oil sands oil, according to a study by Argonne National Laboratory researchers presented at the 238th national meeting of the American Chemical Society last week.
The production of both bio and petroleum feedstocks and fuels requires substantial water input. Biofuel feedstocks such as corn, switchgrass, and agricultural residues need water for growth and conversion to ethanol; petroleum feedstocks such as crude oil and oil sands also require large volumes of water for drilling, extraction, and conversion into petroleum products. In many cases, the Argonne team noted, crude oil production is increasingly water dependent.
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Study Concludes Colorado River Reservoirs Could Bottom Out from Warming, Water Management Business-as-Usual
July 20, 2009
| Colorado River Basin including major dams. Inset (a) shows water demand and losses and supply. Pink: 9-year moving average of the natural flow above Imperial Dam, AZ. Blue: 9-year moving average of the total consumptive use in the Lower and Upper basin. Inset (b) shows 5-year moving average of paleo reconstructed flows at Lees Ferry, AZ. The red line is the natural flow from the observational period. Source: AGU. Click to enlarge. |
All reservoirs along the Colorado River might dry up by mid-century as the West warms, according to a new study led by researchers at the University of Colorado, Boulder. The probability of such a severe shortage by then runs as high as one-in-two, unless current water-management practices change, the researchers report in a paper to be published in the American Geophysical Union (AGU) journal Water Resources Research.
The study’s coauthors looked at the effects of a range of reductions in Colorado River stream flow on future reservoir levels and at the implications of different management strategies. Even under the harshest drying caused by climate change, the large storage capacity of reservoirs on the Colorado might help sustain water supply for a few decades. However, new water management approaches are critical to minimize the chances of fully depleting reservoir storage by mid-century.
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GAO Preliminary Observations on Links Between Water, Biofuels and Electricity; Calls for More Research
July 13, 2009
The Government Accountability Office (GAO) last week provided preliminary observations as testimony to the House Subcommittee on Energy and Environment, Committee on Science and Technology on the water-energy nexus related to biofuels and water and thermoelectric power plants and water.
The subcommittee had requested GAO undertake three studies related to (1) biofuels and water, (2) thermoelectric power plants and water, and (3) oil shale and water.
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Study Finds Water Footprint for Bioenergy Larger Than Other Forms of Energy; Bioelectricity the Smallest, Biodiesel the Largest
June 06, 2009
| Total weighted global average water footprints (blue and green) for major ethanol and biodiesel crops in m3 water per GJ fuel. The yellow marker (also left axis) indicates the total weighted global average WF for bioelectricity from the same crops. The red marker (right axis) indicates liters of water required to produce one liter of fuel. Data: Gerbens-Leenes et al. Click to enlarge. |
Researchers at the University of Twente, Netherlands have calculated the water footprints (WFs) of bioenergy from 12 crops that currently contribute the most to global agricultural production: barley, cassava, maize, potato, rapeseed, rice, rye, sorghum, soybean, sugar beet, sugar cane, and wheat. In addition, their study includes jatropha, an energy crop.
In general they found that bioelectricity is more water-efficient than first-generation biofuels (due largely to the ability to use the entire biomass to produce energy, rather than just the starch or oil fraction of the yield for liquid fuel production). They also found that the WF of bioethanol on a m3 of water per GJ of fuel basis appears to be smaller than that of biodiesel. Their results appeared 2 June in an open access paper in the journal Proceedings of the National Academy of Sciences (PNAS).
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Water Levels Dropping in Some of the World’s Major Rivers
April 22, 2009
| The change in runoff inferred from streamflow records worldwide between 1948 and 2004, with bluish colors indicating more streamflow and reddish colors less. The white land areas indicate inland-draining basins or regions for which there are insufficient data to determine the runoff trends. (Graphic courtesy Journal of Climate, modified by UCAR.) Click to enlarge. |
Rivers in some of the world’s most populous regions are losing water, according to a comprehensive study of global stream flows. The research, led by scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., suggests that the reduced flows in many cases are associated with climate change, and could potentially threaten future supplies of food and water.
The results will be published 15 May in the American Meteorological Society’s Journal of Climate. The research was supported by the National Science Foundation (NSF), NCAR’s sponsor.
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Study Finds Regional Variations in Irrigation Practices Can Push Corn Ethanol Water Requirements 3x Higher Than Earlier Estimates; Need to Account for Regional Specifics in Mandates
April 08, 2009
| Top: County-level corn production and ethanol facilities in 2007. The graph illustrates the proximity of ethanol facilities to corn production. Bottom: EWe and TCW of each state as of 2007. The foreground bar height indicates the EWe of each state, with the portion of ground and surface water indicated by color. The TCW, as measured by a state’s EWe and ethanol production (seen in the background), illustrates local and regional ethanol-induced impacts. Credit: ACS. Click to enlarge. |
Researchers at the University of Minnesota have estimated state-level field-to-pump water requirements of corn ethanol production across the US. Their results find that corn ethanol’s water requirements can range from 5 to 2,138 L per liter of ethanol depending on regional irrigation practices. Prior studies have estimated that corn ethanol requires 263-784 L L-1of water from corn farm to fuel pump.
Based on their calculations using state-level water use data, Sangwon Suh and colleagues also found that the national ethanol-production-weighted average water requirement in the US was 142 L L-1 in 2007— much lower than what was previously estimated in other studies. The new paper is scheduled for the 15 April 15 issue of the ACS journal Environmental Science & Technology.
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Business Leaders Call for Linking Water, Energy and Climate in Global Talks
March 19, 2009
| Log scale plot of illustrative water consumption by energy-related activity. In the examples cited in the report, biomass for biofuels has the largest and widest ranging footprint: from 24,000 m3 per 1,000 GJ in the Netherlands to 143,000 m3 per 1,000 GJ in Zimbabwe. Data: WBCSD (2009). Click to enlarge. |
Business leaders from some of the world’s biggest companies called for water, energy and climate change issues to be linked in global negotiations, such as the international climate talks due to culminate in Copenhagen in December.
The business leaders were speaking at the launch of a report by the World Business Council for Sustainable Development (WBCSD) at the 5th World Water Forum in Istanbul. The report, Water, Energy and Climate Change: A contribution from the business community says water, energy and climate change are inextricably linked. The World Water Forum is expected to produce a ministerial statement calling for proactive policies on water issues.
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Report Finds Water Stress Rapidly Becoming Key Strategic Risk to Commerce; Impending Water/Energy Collision
March 17, 2009
by Jack Rosebro
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| Water consumption or withdrawals per unit of energy produced, by energy type, in the United States. Source: DHI Group. Click to enlarge. |
A Pacific Institute report commissioned by Ceres, whose Investor Network on Climate Risk advises investors with more than US$7 trillion in assets, concludes that impacts of declining water quality and availability will be “far-reaching” for business and industry in the developed as well as the developing world, and that companies which address water stress as a key strategic risk will be better positioned to adjust to negative effects such as reduced water allotments, rising water costs, community opposition, and increased public scrutiny of corporate water practices.
Among the increasing challenges is that while the sourcing, processing, and delivery of clean water is becoming more energy-intensive, the extraction and refining of fossil fuels and their substitutes is trending towards increasing water requirements per unit of fuel produced as energy companies work with progressively lower grade resources.
