680 research outputs found
Solar Power and the Electric Grid, Energy Analysis
In today’s electricity generation system, different resources make different contributions to the electricity grid. This fact sheet illustrates the roles of distributed and centralized renewable energy technologies, particularly solar power, and how they will contribute to the future electricity system. The advantages of a diversified mix of power generation systems are highlighted
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Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Date Report No. 3: Diesel Fuel Sulfur Effects on Particulate Matter Emissions
The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim report covers the effects of diesel fuel sulfur level on particulate matter emissions for four technologies
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Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Data Report No. 1
The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim data report summarizes results as of August, 1999, on the status of the test programs being conducted on three technologies: lean-NO{sub x} catalysts, diesel particulate filters and diesel oxidation catalysts
Renewable energy production and demand dataset for the energy system of Colombia
During the last decades, an increasing number of studies have focused their attention on the development of energy system models in order to facilitate sustainable energy planning strategies and understand the technical challenges associated with the integration of renewable energy sources. However, these models usually require detailed and large amount of data as inputs. The data presented in this article provides key inputs and modelling assumptions adopted in the research paper titled “Large scale integration of renewable energy sources (RES) in the future Colombian energy system” [1]. These datasets can be used by researchers and policymakers in order to analyse different pathways oriented to the development of low carbon strategies for Colombia and countries with similar energy systems
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Quantifying the increasing sensitivity of power systems to climate variability
Large quantities of weather-dependent renewable energy generation are expected in power systems under climate change mitigation policies, yet little attention has been given to the impact of long term climate variability. By combining state-ofthe-art multi-decadal meteorological records with a parsimonious representation of a power system, this study characterises the impact of year-to-year climate variability on multiple aspects of the power system of Great Britain (including coal, gas and
nuclear generation), demonstrating why multi-decadal approaches are necessary. All aspects of the example system are impacted by inter-annual climate variability, with the impacts being most pronounced for baseload generation. The impacts of inter-annual climate variability increase in a 2025 wind-power scenario, with a 4-fold increase in
the inter-annual range of operating hours for baseload such as nuclear. The impacts on peak load and peaking-plant are comparably small. Less than 10 years of power supply and demand data are shown to be insuffcient for providing robust power system planning guidance. This suggests renewable integration studies - widely used in policy, investment and system design - should adopt a more robust approach to climate characterisation
Life cycle energy and environmental analysis of a microgrid power pavilion
Microgrids—generating systems incorporating multiple distributed generator sets linked together to provide local electricity and heat—are one possible alterative to the existing centralized energy system. Potential advantages of microgrids include flexibility in fuel supply options, the ability to limit emissions of greenhouse gases, and energy efficiency improvements through combined heat and power (CHP) applications. As a case study in microgrid performance, this analysis uses a life cycle assessment approach to evaluate the energy and emissions performance of the NextEnergy microgrid Power Pavilion in Detroit, Michigan and a reference conventional system. The microgrid includes generator sets fueled by solar energy, hydrogen, and natural gas. Hydrogen fuel is sourced from both a natural gas steam reforming operation and as a by-product of a chlorine production operation. The chlorine plant receives electricity exclusively from a hydropower generating station. Results indicate that the use of this microgrid offers a total energy reduction potential of up to 38%, while reductions in non-renewable energy use could reach 51%. Similarly, emissions of CO 2 , a key global warming gas, can be reduced by as much as 60% relative to conventional heat and power systems. Hydrogen fuels are shown to provide a net energy and emissions benefit relative to natural gas only when sourced primarily from the chlorine plant. Copyright © 2006 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55887/1/1223_ftp.pd
Privacy-enhancing Aggregation of Internet of Things Data via Sensors Grouping
Big data collection practices using Internet of Things (IoT) pervasive
technologies are often privacy-intrusive and result in surveillance, profiling,
and discriminatory actions over citizens that in turn undermine the
participation of citizens to the development of sustainable smart cities.
Nevertheless, real-time data analytics and aggregate information from IoT
devices open up tremendous opportunities for managing smart city
infrastructures. The privacy-enhancing aggregation of distributed sensor data,
such as residential energy consumption or traffic information, is the research
focus of this paper. Citizens have the option to choose their privacy level by
reducing the quality of the shared data at a cost of a lower accuracy in data
analytics services. A baseline scenario is considered in which IoT sensor data
are shared directly with an untrustworthy central aggregator. A grouping
mechanism is introduced that improves privacy by sharing data aggregated first
at a group level compared as opposed to sharing data directly to the central
aggregator. Group-level aggregation obfuscates sensor data of individuals, in a
similar fashion as differential privacy and homomorphic encryption schemes,
thus inference of privacy-sensitive information from single sensors becomes
computationally harder compared to the baseline scenario. The proposed system
is evaluated using real-world data from two smart city pilot projects. Privacy
under grouping increases, while preserving the accuracy of the baseline
scenario. Intra-group influences of privacy by one group member on the other
ones are measured and fairness on privacy is found to be maximized between
group members with similar privacy choices. Several grouping strategies are
compared. Grouping by proximity of privacy choices provides the highest privacy
gains. The implications of the strategy on the design of incentives mechanisms
are discussed
Compressed-Liquid Energy Storage with an Adsorption-based Vapor Accumulator for Solar-Driven Vapor Compression Systems in Residential Cooling
A cycle-integrated energy storage strategy for vapor-compression refrigeration is proposed wherein thermo-mechanical energy is stored as compressed liquid.A compressed-liquid tank is integrated into the liquid line of the system by means of an adsorption-based vapor accumulator in the vapor line. Energy is retrieved through expansion of the compressed liquid, which allows for a tunable evaporator temperature. A thermodynamic model is developed to assess the system performance, with storage incorporated, for solar residential cooling in two locations with contrasting ambient temperature profiles. Ammonia, R134a, and propane, all paired with activated carbon as adsorbent, are evaluated.A high cold thermal energy storage density is achieved when operated with ammonia. However, the accumulator suppresses the coefficient of performance of the system because work is required to extract refrigerant from the adsorbent. Practical feasibility of the proposed storage strategy calls for the development of nontoxic refrigerant–adsorbent pairs with more favorable adsorption behavior
Potential and limitations of CsBi3I10 as a photovoltaic material
Herein we demonstrate the dry synthesis of CsBi3I10 both as a free-standing material and in the form of homogeneous thin films, deposited by thermal vacuum deposition. Chemical and optical characterization shows high thermal stability, phase purity, and photoluminescence centered at 700 nm, corresponding to a bandgap of 1.77 eV. These characteristics make CsBi3I10 a promising low-toxicity material for wide bandgap photovoltaics. Nevertheless, the performance of this material as a semiconductor in solar cells remains rather limited, which can be at least partially ascribed to a low charge carrier mobility, as determined from pulsed-radiolysis time-resolved microwave conductivity. Further developments should focus on understanding and overcoming the current limitations in charge mobility, possibly by compositional tuning through doping and/or alloying, as well as optimizing the thin film morphology which may be another limiting factor
Techno-economic assessments of advanced Combined Cycle Gas Turbine(CCGT) technology for the new electricity market in the United ArabEmirates
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