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Now showing items 1 - 16 of 272

  • Optimizing the layout of onshore wind farms to minimize noise

    Wu, Xiawei   Hu, Weihao   Huang, Qi   Chen, Cong   Jacobson, Mark Z.   Chen, Zhe  

    As wind farm numbers and areas increase worldwide, it has become increasingly important to examine the impact of wind energy on the surrounding environment. One effect in some scenarios is noise, which depends on the type and age of the wind turbines and the distances between them and the residential buildings. Previous research on wind farm layout optimization has been generally aimed at achieving the minimum investment cost or maximum captured energy. This approach does not entirely align with minimizing noise. This paper focuses on an optimal layout for a wind farm considering its noise, without sacrificing power production. By optimizing the wind farm layout, the minimum noise is set as the basic objective, and both the wake effect and distances among wind turbines are considered. The basic particle swarm optimization algorithm and its evolutionary version are adopted and compared for better performance of calculation cost. Two strategies are presented to address the problems in various scenarios and to demonstrate the applicability of the proposed method and its effectiveness in designing layouts that minimize noise. Compared to a reference layout, a stringent noise control strategy could reduce the noise by 11%, even if minor, and increase the power production by 3.1%. A flexible strategy could reduce the noise by 5.7% and increase the power production by 3.1%.
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  • The health and climate impacts of carbon capture and direct air capture

    Jacobson, Mark Z.  

    Data from a coal with carbon capture and use (CCU) plant and a synthetic direct air carbon capture and use (SDACCU) plant are analyzed for the equipment's ability, alone, to reduce CO2. In both plants, natural gas turbines power the equipment. A net of only 10.8% of the CCU plant's CO2-equivalent (CO(2)e) emissions and 10.5% of the CO2 removed from the air by the SDACCU plant are captured over 20 years, and only 20-31%, are captured over 100 years. The low net capture rates are due to uncaptured combustion emissions from natural gas used to power the equipment, uncaptured upstream emissions, and, in the case of CCU, uncaptured coal combustion emissions. Moreover, the CCU and SDACCU plants both increase air pollution and total social costs relative to no capture. Using wind to power the equipment reduces CO(2)e relative to using natural gas but still allows air pollution emissions to continue and increases the total social cost relative to no carbon capture. Conversely, using wind to displace coal without capturing carbon reduces CO(2)e, air pollution, and total social cost substantially. In sum, CCU and SDACCU increase or hold constant air pollution health damage and reduce little carbon before even considering sequestration or use leakages of carbon back to the air. Spending on capture rather than wind replacing either fossil fuels or bioenergy always increases total social cost substantially. No improvement in CCU or SDACCU equipment can change this conclusion while fossil fuel emissions exist, since carbon capture always incurs an equipment cost never incurred by wind, and carbon capture never reduces, instead mostly increases, air pollution and fuel mining, which wind eliminates. Once fossil fuel emissions end, CCU (for industry) and SDACCU social costs need to be evaluated against the social costs of natural reforestation and reducing nonenergy halogen, nitrous oxide, methane, and biomass burning emissions.
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  • Coupled Chemistry-Climate Effects from 2050 Projected Aviation Emissions

    Gettelman, Andrew   Chen, Chih-Chieh   Jacobson, Mark Z.   Cameron, Mary A.   Wuebbles, Donald J.   Khodayari, Arezoo  

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  • Ring of impact from the mega-urbanization of Beijing between 2000 and 2009

    Jacobson, Mark Z.   Nghiem, Son V.   Sorichetta, Alessandro   Whitney, Natasha  

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  • A 100% wind,water,sunlight (WWS) all-sector energy plan for Washington State

    Jacobson, Mark Z.   Delucchi, Mark A.   Bazouin, Guillaume   Dvorak, Michael J.   Arghandeh, Reza   Bauer, Zack A. F.   Cotte, Ariane   de Moor, Gerrit M. T. H.   Goldner, Elissa G.   Heier, Casey   Holmes, Randall T.   Hughes, Shea A.   Jin, Lingzhi   Kapadia, Moiz   Menon, Carishma   Mullendore, Seth A.   Paris, Emily M.   Provost, Graham A.   Romano, Andrea R.   Srivastava, Chandrika   Vencill, Taylor A.   Whitney, Natasha S.   Yeskoo, Tim W.  

    This study analyzes the potential and consequences of Washington State's use of wind, water, and sunlight (WWS) to produce electricity and electrolytic hydrogen for 100% of its all-purposes energy (electricity, transportation, heating/cooling, industry) by 2050, with 80-85% conversion by 2030. Electrification plus modest efficiency measures can reduce Washington State's 2050 end-use power demand by similar to 39.9%, with similar to 80% of the reduction due to electrification, and can stabilize energy prices since WWS fuel costs are zero. The remaining demand can be met, in one scenario, with similar to 35% onshore wind, similar to 13% offshore wind, similar to 10.73% utility-scale PV, similar to 2.9% residential PV, similar to 1.5% commercial/government PV, similar to 0.65% geothermal, similar to 0.5% wave, similar to 0.3% tidal, and similar to 35.42% hydropower. Converting will require only 0.08% of the state's land for new footprint and similar to 2% for spacing between new wind turbines (spacing that can be used for multiple purposes). It will further result in each person in the state saving similar to$85/yr in direct energy costs and similar to$950/yr in health costs [eliminating similar to 830 (190-1950)/yr statewide premature air pollution mortalities] while reducing global climate costs by similar to$4200/person/yr (all in 2013 dollars). Converting will therefore improve health and climate while reducing costs. (C) 2015 Elsevier Ltd. All rights reserved.
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  • Taming hurricanes with arrays of offshore wind turbines

    Jacobson, Mark Z.   Archer, Cristina L.   Kempton, Willett  

    Hurricanes are causing increasing damage to many coastal regions worldwide(1,2). Offshore wind turbines can provide substantial clean electricity year-round, but can they also mitigate hurricane damage while avoiding damage to themselves? This study uses an advanced climate-weather computer model that correctly treats the energy extraction of wind turbines(3,4) to examine this question. It finds that large turbine arrays (300+ GW installed capacity) may diminish peak near-surface hurricane wind speeds by 25-41 m s(-1) (56-92 mph) and storm surge by 6-79%. Benefits occur whether turbine arrays are placed immediately upstream of a city or along an expanse of coastline. The reduction in wind speed due to large arrays increases the probability of survival of even present turbine designs. The net cost of turbine arrays (capital plus operation cost less cost reduction from electricity generation and from health, climate, and hurricane damage avoidance) is estimated to be less than today's fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm surge damage.
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  • Flexibility mechanisms and pathways to a highly renewable US electricity future

    Frew, Bethany A.   Becker, Sarah   Dvorak, Michael J.   Andresen, Gorm B.   Jacobson, Mark Z.  

    This study explores various scenarios and flexibility mechanisms to integrate high penetrations of renewable energy into the US (United States) power grid. A linear programming model - POWER (Power system Optimization With diverse Energy Resources) - is constructed and used to (1) quantify flexibility cost-benefits of geographic aggregation, renewable overgeneration, storage, and flexible electric vehicle charging, and (2) compare pathways to a fully renewable electricity system. Geographic aggregation provides the largest flexibility benefit with similar to 5-50% cost savings, but each region's contribution to the aggregate RPS (renewable portfolio standard) target is disproportionate, suggesting the need for regional-and-resource-specific RPS targets. Electric vehicle charging yields a lower levelized system cost, revealing the benefits of demand-side flexibility. However, existing demand response price structures may need adjustment to encourage optimal flexible load in highly renewable systems. Two scenarios with RPS targets from 20% to 100% for the US (peak load similar to 729 GW) and California (peak load similar to 62 GW) find each RPS target feasible from a planning perspective, but with 2x the cost and 3x the over generation at a 100% versus 80% RPS target. Emission reduction cost savings for the aggregated US system with an 80% versus 20% RPS target are roughly $200 billion/year, outweighing the $80 billion/year cost for the same RPS range. (C) 2016 Elsevier Ltd. All rights reserved.
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  • A 100% wind, water, sunlight (WWS) all-sector energy plan for Washington State

    Jacobson, Mark Z.   Delucchi, Mark A.   Bazouin, Guillaume   Dvorak, Michael J.   Arghandeh, Reza   Bauer, Zack A.F.   Cotte, Ariane   de Moor, Gerrit M.T.H.   Goldner, Elissa G.   Heier, Casey   Holmes, Randall T.   Hughes, Shea A.   Jin, Lingzhi   Kapadia, Moiz   Menon, Carishma   Mullendore, Seth A.   Paris, Emily M.   Provost, Graham A.   Romano, Andrea R.   Srivastava, Chandrika   Vencill, Taylor A.   Whitney, Natasha S.   Yeskoo, Tim W.  

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  • Sensitivity of particle loss to the Kelvin effect in LES of young contrails

    Inamdar, Aniket R.   Naiman, Alexander D.   Lele, Sanjiva K.   Jacobson, Mark Z.  

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  • Meeting the world's energy needs entirely with wind, water, and solar power

    Delucchi, Mark A.   Jacobson, Mark Z.  

    The combustion of fossil fuels is largely responsible for the problems of climate change, air pollution, and energy insecurity. A combination of wind, water, and solar power is the best alternative to fossil fuels, the authors write, because renewable energy sources have near-zero emissions of greenhouse gases and other air pollutants, no long-term waste disposal problems, and no risks of catastrophic accidents. Compared with nuclear energy and biomass energy, the authors find that wind, water, and solar power, alone, would not only be advantageous but also feasible to meet 100 percent of the world's energy needs. They explain how renewable energy systems can be designed and operated to ensure that power generation reliably matches demand; they calculate that these energy sources would cost less than fossil fuels when all costs to society are considered; and they recommend policies for easing the transition to energy systems based entirely on wind, water, and solar power.
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  • Effects of aggregating electric load in the United States

    Corcoran, Bethany A.   Jenkins, Nick   Jacobson, Mark Z.  

    This study quantifies the effects of aggregating electric load over various combinations (Aggregation Groupings) of the 10 Federal Energy Regulatory Commission (FERC) regions in the contiguous U.S. Generator capacity capital cost savings, load energy shift operating cost savings, reserve requirement cost savings, and transmission costs due to aggregation were calculated for each Aggregation Grouping. Eight scenarios of Aggregation Groupings over the U.S. were formed to estimate overall system cost. Transmission costs outweighed cost savings due to aggregation for all scenarios and nearly all Aggregation Groupings. East-west transmission layouts had the highest overall cost, and interconnecting ERCOT to adjacent FERC Regions resulted in increased costs, both due to limited existing transmission capacity. This study found little economic benefit of aggregating electric load alone (e.g., without aggregating renewable generators simultaneously), except in the West and Northwest U.S. If aggregation of load alone is desired, small, regional consolidations yield the lowest overall cost. This study neither examines nor precludes benefits of interconnecting geographically-dispersed renewable generators with load. It also does not consider effects from sub-hourly load variability, fuel diversity and price uncertainty, energy price differences due to congestion, or uncertainty due to forecasting errors; thus, results are valid only for the assumptions made. (C) 2012 Elsevier Ltd. All rights reserved.
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  • Geographical and seasonal variability of the global "practical" wind resources

    Archer, Cristina L.   Jacobson, Mark Z.  

    This paper provides global and seasonal estimates of the "practical" wind power obtained with a 3-D numerical model (GATOR-GCMOM) that dynamically calculates the instantaneous wind power of a modern 5 MW wind turbine at 100-m hub height at each time step. "Practical" wind power is defined as that delivered from wind turbines in high-wind locations (year-average 100-m wind speed >=3D 7 m/s) over land and near-shore, excluding both polar regions, mountainous, and conflicting land use areas, and including transmission, distribution, and wind farm array losses. We found that seasonal variations in the global practical wind resources are significant. The highest net land plus near-shore capacity factors globally are found during December January February and the lowest during June July August. The capacity factors in the transitional seasons (March April May and September October November) are rather similar to one another in terms of geographical patterns and frequency distributions. The yearly-average distributions of capacity factors, whether in terms of geographic patterns or frequency distributions, differ from those in all four seasons, although they are closest to the transitional seasons. Regional practical wind resources are sensitive to seasons and to thresholds in year-average wind speed and bathymetry, but are more than enough to supply local electricity demand in all regions except Japan. (C) 2013 Elsevier Ltd. All rights reserved.
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  • Where is the ideal location for a US East Coast offshore grid?

    Dvorak, Michael J.   Stoutenburg, Eric D.   Archer, Cristina L.   Kempton, Willett   Jacobson, Mark Z.  

    This paper identifies the location of an "ideal"offshore wind energy (OWE) grid on the U. S. East Coast that would (1) provide the highest overall and peak-time summer capacity factor, (2) use bottom-mounted turbine foundations (depth <= 50 m), (3) connect regional transmissions grids from New England to the Mid-Atlantic, and (4) have a smoothed power output, reduced hourly ramp rates and hours of zero power. Hourly, high-resolution mesoscale weather model data from 2006-2010 were used to approximate wind farm output. The offshore grid was located in the waters from Long Island, New York to the Georges Bank, approximate to 450 km east. Twelve candidate 500 MW wind farms were located randomly throughout that region. Four wind farms (2000 MW total capacity) were selected for their synergistic meteorological characteristics that reduced offshore grid variability. Sites likely to have sea breezes helped increase the grid capacity factor during peak time in the spring and summer months. Sites far offshore, dominated by powerful synoptic-scale storms, were included for their generally higher but more variable power output. By interconnecting all 4 farms via an offshore grid versus 4 individual interconnections, power was smoothed, the no-power events were reduced from 9% to 4%, and the combined capacity factor was 48% (gross). By interconnecting offshore wind energy farms approximate to 450 km apart, in regions with offshore wind energy resources driven by both synoptic-scale storms and mesoscale sea breezes, substantial reductions in low/no-power hours and hourly ramp rates can be made. Citation: Dvorak, M. J., E. D. Stoutenburg, C. L. Archer, W. Kempton, and M. Z. Jacobson (2012), Where is the ideal location for a US East Coast offshore grid?, Geophys. Res. Lett., 39, L06804, doi: 10.1029/ 2011GL050659.
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  • Effects of Urban Surfaces and White Roofs on Global and Regional Climate

    Jacobson, Mark Z.   Ten Hoeve, John E.  

    Land use, vegetation, albedo, and soil-type data are combined in a global model that accounts for roofs and roads at near their actual resolution to quantify the effects of urban surface and white roofs on climate. In 2005, similar to 0.128% of the earth's surface contained urban land cover, half of which was vegetated. Urban land cover was modeled over 20 years to increase gross global warming (warming before cooling due to aerosols and albedo change are accounted for) by 0.06-0.11 K and population-weighted warming by 0.16-0.31 K. based on two simulations under different conditions. As such, the urban heat island (UHI) effect may contribute to 2%-4% of gross global warming, although the uncertainty range is likely larger than the model range presented, and more verification is needed. This may be the first estimate of the UHI effect derived from a global model while considering both UHI local heating and large-scale feedbacks. Previous data estimates of the global UHI, which considered the effect of urban areas but did not treat feedbacks or isolate temperature change due to urban surfaces from other causes of urban temperature change, imply a smaller UHI effect but of similar order. White roofs change surface albedo and affect energy demand. A worldwide conversion to white roofs, accounting for their albedo effect only, was calculated to cool population-weighted temperatures by similar to 0.02 K but to warm the earth overall by similar to 0.07 K. White roof local cooling may also affect energy use, thus emissions, a factor not accounted for here. As such, conclusions here regarding white roofs apply only to the assumptions made.
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  • Air Pollution and Global Warming (History, Science, and Solutions) || Preface

    Jacobson, Mark Z.  

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  • California offshore wind energy potential

    Dvorak, Michael J.   Archer, Cristina L.   Jacobson, Mark Z.  

    This study combines multi-year mesoscale modeling results, validated using offshore buoys with high-resolution bathymetry to create a wind energy resource assessment for offshore California (CA). The siting of an offshore wind farm is limited by water depth, with shallow water being generally preferable economically. Acceptable depths for offshore wind farms are divided into three categories: <= 20 m depth for monopile turbine foundations, <= 50 m depth for multi-leg turbine foundations, and <= 200 m depth for deep water floating turbines. The CA coast was further divided into three logical areas for analysis: Northern, Central, and Southern CA. A mesoscale meteorological model was then used at high horizontal resolution (5 and 1.67 km) to calculate annual 80 m wind speeds (turbine hub height) for each area, based on the average of the seasonal months January, April, July, and October of 2005/2006 and the entirety of 2007 (12 months). A 5 MW offshore wind turbine was used to create a preliminary resource assessment for offshore CA. Each geographical region was then characterized by its coastal transmission access, water depth, wind turbine development potential, and average 80 m wind speed. Initial estimates show that 1.4-2.3 GW, 4.4-8.3 GW, and 52.8-64.9 GW of deliverable power could be harnessed from offshore CA using monopile, multi-leg, and floating turbine foundations, respectively. A single proposed wind farm near Cape Mendocino could deliver an average 800 MW of gross renewable power and reduce CA's current carbon emitting electricity generation 4% on an energy basis. Unlike most of California's land based wind farms which peak at night, the offshore winds near Cape Mendocino are consistently fast throughout the day and night during all four seasons. (C) 2009 Elsevier Ltd. All rights reserved.
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