R&D Forum

Issue 7 and Volume 29.

EPRI releases report on hydro greenhouse gas emissions

EPRI announces availability of a new report, The Role of Hydropower Reservoirs in Greenhouse Gas Emissions.

This report describes the results of two initial tasks in a multi-year study to assess the importance of carbon cycling and greenhouse gas (GHG) emissions from hydro reservoirs and operations in the U.S. The potential for GHG emissions from hydropower projects adds uncertainty to future regulatory and market contexts for hydro, the report says.

Immediate concerns include the potential for reservoir GHG emissions to limit hydro participation in renewable portfolio standards, economic incentives for renewable energy development, generation scheduling to firm up intermittent energy sources, premium pricing for preferable energy sources, and marketable renewable energy credits.

Findings of the report include:

  • Gross GHG emissions from reservoirs are not zero, but it is less certain if there is a net emission of GHG;
  • Environmental assessments of projects complying with the National Environmental Policy Act lack a scientific basis for asserting the absence or presence of GHG emissions because of the dearth of data for temperate reservoirs;
  • Comprehensive studies involving field measurements and development of predictive models are required to assess the contribution of U.S. reservoirs to anthropogenic GHG emissions;
  • Field GHG measurements must include the three major emission pathways (reservoir surfaces, dams, and tailwaters), as well as assessment of temporal dynamics and the effect of reservoir operations; and
  • Data from field measurements can be used to develop a predictive model of the factors controlling GHG emission rates that will allow extrapolation of the empirical data to other reservoirs.
The authors conducted a literature review and synthesis to establish what is known about GHG emissions from hydropower reservoirs and other water bodies. They then reviewed GHG assessment protocols to identify one appropriate for U.S. reservoirs. EPRI plans a follow-up effort with the U.S. Department of Energy that involves monitoring representative U.S. reservoirs to resolve the uncertainties noted in the report.

– To access the free report, visit www.epri.com and search for 1017971 or contact EPRI Customer Assistance Center, (1) 800-313-3774; E-mail: [email protected].

Study assesses water resources in the California Bay-Delta

The first report is available in a National Research Council (NRC) review of water resources in the California Bay-Delta. The Bay-Delta estuary plays a central role in the distribution of water from the state’s wetter northern regions to its southern, arid, and populous cities and agricultural areas, the report says.

The 104-page report is titled “A Scientific Assessment of Alternatives for Reducing Water Management Effects on Threatened and Endangered Fishes in California’s Bay Delta.” The report is intended to address scientific questions, assumptions, and conclusions underlying water management alternatives in two biological opinions issued by the Fish and Wildlife Service (FWS) and National Marine Fisheries Service. These opinions required changes in water operations and related actions to avoid jeopardizing the continued existence and potential for recovery of delta smelt, winter and fall run chinook salmon, Central Valley steelhead, and green sturgeon. Those changes reduced the amount of water available for other uses, such as water supply, agricultural irrigation, and hydropower production.

The review focused on three issues:

  • Are there reasonable and prudent alternatives that would provide equal or greater protection for the listed species and their habitat while having lesser effects to other water uses than those adopted in the biological opinions?
  • Are there provisions in the biological opinions to resolve the potential for actions that would benefit one listed species while causing negative effects on another?
  • What are the effects of other stressors (e.g., pesticides, ammonia discharge, invasive species) on federally listed and other at-risk species in the Bay-Delta?
The principal conclusion is that reversing or even slowing the declines of the above species cannot be accomplished immediately. With regard to the two biological opinions, the report concludes that the reasonable and prudent alternatives they contain lack an integrated quantitative analytical framework that ties the various actions together within species, between smelt and salmonid species, and across the watershed. This type of systematic, formalized analysis is necessary to provide an objective determination of the net effect of all actions on the listed species and on water users, the report says.

The committee plans to release a second report in late 2011 that addresses how to most effectively incorporate science and adaptive management concepts into holistic programs for management and restoration of the Bay-Delta.

– To download a free PDF of this report, visit the Internet: www.nap.edu and search for Bay Delta.

Ductile iron pipe performs well during earthquakes

Ductile iron pipe with restrained joints sustain only minimal structural damage during earthquakes, the results of a recent study indicate.

The study, performed by AMERICAN Cast Iron Pipe in Birmingham, Ala., reviewed data about pipe failures during modern-day earthquakes. These include Prince William Sound, Alaska, 1964; Loma Prieta, Calif., 1989; and Northridge, Calif., 1994. During earthquakes, pipelines are particularly vulnerable at locations of ground rupture as a result of soil liquefaction, landslides, or fault slippage.

Results indicate that ductile iron pipe and joints performed the best. This likely is because of recent advances in restrained, flexible expansion/contraction couplings for seismic areas. Good jointing techniques are required to enable the pipeline to increase or shorten in length and to rotate or bend without leakage, failure, or interruption to service.

According to the study, asbestos-cement pipe had the worst failure rate, and plastic pipe was more likely to pull apart at the joints.

AMERICAN Cast Iron Pipe manufactures ductile iron pipe, spiral-welded steel pipe, valves, and more.

Tucker, Michael S., “Performance of Ductile-Iron Pipe in Earthquake/Seismic Zones,” Journal of the American Water Works Association, Volume 102, No. 5, May 2010, http://www.awwa.org/publications/AWWAJournalArticle.cfm?itemnumber=54489.

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