268 research outputs found
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Prospects for Hydrogen in the Future Energy System
Hydrogen is a high quality energy carrier that could be produced at global scale, via thermochemical processing of hydrocarbons, such as natural gas, coal or biomass, or water electrolysis using any source of electricity including renewables, such as wind or solar, or nuclear power. Hydrogen is receiving renewed attention driven by growing concerns about climate change, air quality and integration of variable renewable energy into the energy system. Recent energy/economic studies suggest that hydrogen and fuel cells could be important technologies for simultaneously addressing these challenges in a future renewable-intensive, low carbon energy system. In this paper, we review the technical and economic status of hydrogen and fuel cell technologies, progress toward commercialization, and the role of policy. We discuss timing, barriers, costs and benefits of a hydrogen transition, focusing on vehicle and energy storage applications. Finally, we suggest guidelines for future policies guiding a hydrogen transition
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Utilizing Highway Rest Areas for Electric Vehicle Charging: Economics and Impacts on Renewable Energy Penetration in California
California policy is incentivizing rapid adoption of zero emission electric vehicles for light-duty and freight applications. This project explored how locating charging facilities at California’s highway rest stops might impact electricity demand, grid operation, and integration of renewables like solar and wind into California’s energy mix. Assuming a growing population of electric vehicles to meet state goals, state-wide growth of electricity demand was estimated, and the most attractive rest stop locations for siting chargers identified. Using a California-specific electricity dispatch model developed at UC Davis, the project estimated how charging vehicles at these stations would impact renewable energy curtailment in California. It estimated the impacts of charging infrastructures on California’s electricity system and how they can be utilized to decrease the duck curve effect resulting from a large amount of solar energy penetration by 2050.View the NCST Project Webpag
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Quantifying the Economic Value of Vehicle-Grid Integration: A Case Study of Dynamic Pricing in the Sacramento Municipal Utility District
This study develops a stochastic-systems approach in modeling vehicle-grid integration (VGI), where load management strategies can be compared in terms of their economic value to plug-in electric vehicle (PEV) consumers and their local utility companies. The proposed methodology is demonstrated in an assessment of VGI for the Sacramento Municipal Utility District (SMUD) in California. Monte-Carlo simulations have been performed to randomly assign PEV charging characteristics of the households based on given statistical distributions. Consumer adoption of time-of-use (TOU) rates is modeled as an optimization problem where consumers seek the earliest PEV charge start time among the charge schedules resulting lowest cost and satisfying their transportation needs. The preliminary results show that, considering today’s grid system, the deployment of 60,000 PEVs in Sacramento Region will have significant but manageable impacts. These impacts included increasing annual peak demand by 86MWs (5%), and overloading up to 101 neighborhood transformers in the distribution system. On the other hand, adopting proper TOU rates presents a high potential for minimizing these negative impacts of widespread PEV deployment on the grid. The proposed methodology provided several improvements to the VGI modeling literature. These improvements included combining assessments for generation and distribution systems in the same model, and advancing uncertainty analysis for the PEV consumer behavior with considering real world data sets
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CONCEPTUAL DESIGN OF OPTIMIZED FOSSIL ENERGY SYSTEMS WITH CAPTURE AND SEQUESTRATION OF CARBON DIOXIDE
In this semi-annual progress report, we describe research results from an ongoing study of fossil hydrogen energy systems with CO{sub 2} sequestration. This work was performed under NETL Award No. DE-FC26-02NT41623, during the six-month period September 2002 through March 2003. The primary objective of the study is to better understand system design issues and economics for a large-scale fossil energy system co-producing H{sub 2} and electricity with CO{sub 2} sequestration. This is accomplished by developing analytic and simulation methods for studying the entire system in an integrated way. We examine the relationships among the different parts of a hydrogen energy system, and attempt to identify which variables are the most important in determining both the disposal cost of CO{sub 2} and the delivered cost of H{sub 2}. A second objective is to examine possible transition strategies from today's energy system toward one based on fossil-derived H{sub 2} and electricity with CO{sub 2} sequestration. We are carrying out a geographically specific case study of development of a fossil H{sub 2} system with CO{sub 2} sequestration, for the Midwestern United States, where there is presently substantial coal conversion capacity in place, coal resources are plentiful and potential sequestration sites in deep saline aquifers are widespread
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Integrating Plug-in Electric Vehicles into the Grid: Policy Entrepreneurship in California
The deployment of large numbers of plug-in electric vehicles (PEVs), in order to satisfy zero-emission-vehicle (ZEV) goals in California, brings both potential benefits and costs for the electric grid. Since early 2009, the issue of so-called vehicle-grid integration (VGI) has become a center-stage policy discussion among the electricity and transportation sectors. By conducting a policy process analysis, this research addresses the questions of how the policy process for VGI regulations has been formed in California, and what have been the major challenges in policy-making. A series of interviews were conducted between with representatives of 18 organizations from the government, electric utility, and PEV sectors. The qualitative data is analyzed under the three dimensions of policy process; problem, politics, and policy as suggested by Multiple Streams framework (Kingdon, 1995). The results show that a policy window for VGI regulations was opened for the first time by the political stream, through State Senate Bill 626 in 2009, and later, supported by the Governor’s ZEV action plan in 2012. In response, the California Public Utility Commission became a policy entrepreneur, and has adopted an incremental policy-making strategy targeting investor-owned utilities (IOUs). The two largest barriers facing an effective policy solution are identified as the complexities involved in quantifying economic value from VGI and the feasibility concerns about adopting VGI enabling technologies on the grid
Estimating prevalence of overweight and obesity at the neighborhood level: the value of maternal height and weight data available on birth certificate records
<p>Abstract</p> <p>Objective</p> <p>To determine the value of maternal height and weight data on birth certificate records when estimating prevalence of overweight and obese adults at the neighborhood level.</p> <p>Research Design and Methods</p> <p>Regression analysis was used to determine how much variation in the percentage of the adult population with a body mass index (BMI) of ≥ 25 (based on survey data) could be accounted for by the percentage of mothers with BMI ≥ 25 (based on birth certificate data) -- alone and in combination with other sociodemographic characteristics of census tracts.</p> <p>Results</p> <p>Alone, the percentage of mothers with BMI ≥ 25 explained more than half (R<sup>2 </sup>= .52) of the variation in the percentage of all residents in census tracts with BMI ≥ 25; in combination with several measures of the sociodemographic characteristics of the census tracts, 75% ( R<sup>2 </sup>= 75.2) of the variation is explained.</p> <p>Conclusions</p> <p>Maternal height and weight data available from birth certificate records may be useful for identifying neighborhoods with relatively high or low prevalence of adult residents who are overweight or obese. This is especially true if used in combination with readily available census data.</p
The risk of child and adolescent overweight is related to types of food consumed
<p>Abstract</p> <p>Background/Aims</p> <p>To investigate the association between the risk of overweight and the consumption of food groups in children and adolescents.</p> <p>Methods</p> <p>We studied 1764 healthy children and adolescents (age 6-19y) attending 16 Seventh-Day Adventist schools and 13 public schools using a 106-item non-quantitative food frequency questionnaire from the late 1980 Child-Adolescent Blood Pressure Study. Logistic regression models were used to compute the risk of overweight according to consumption of grains, nuts, vegetables, fruits, meats/fish/eggs, dairy, and, low nutrient-dense foods (LNDF).</p> <p>Results</p> <p>The frequency of consumption of grains, nuts, vegetables and LNDF were inversely related to the risk of being overweight and dairy increased the risk. Specifically, the odds ratio (95% CI) for children in the highest quartile or tertile of consumption compared with the lowest quartile or tertile were as follows: grains 0.59(0.41-0.83); nuts 0.60(0.43-0.85); vegetables 0.67(0.48-0.94); LNDF 0.43(0.29-0.63); and, dairy 1.36(0.97, 1.92).</p> <p>Conclusion</p> <p>The regular intake of specific plant foods may prevent overweight among children and adolescents.</p
Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.
OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening
Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans
Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have
fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in
25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16
regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of
correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP,
while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in
Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium
(LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region.
Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant
enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the
refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa,
an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of
PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent
signals within the same regio
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