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Laser shock peening (LSP) is a non-contact surface treatment method that has been experimentally found to help increase fracture toughness, induce near-surface compressive residual stress and increase hardness in ceramic materials. Numerous experiments, with associated costs and challenges, are needed to identify the application-specific LSP parameters. Physics-based computational models provide a less expensive and more flexible alternative to performing the requisite experiments, yet the trade-off between computational cost and accuracy of different models needs to be considered. In this work, LSP treatment finite element simulations are executed using a calibrated Drucker-Prager (DP) plasticity model combined with a Mie-Gruneisen equation of state as well as Johnson-Cook rate dependence and a damage initiation criterion. Unlike existing Johnson-Holmquist (JH) methods, the calibrated DP constitutive model does not require damage model parameters to be continually updated with deformation, resulting in lower computational time. Near-surface compressive residual stress, predicted by the model, is compared to measurements reported in recent experimental studies. At the lowest pulse energy tested (1 J) an approximate 5% difference exists between the simulated RS and that measured by Raman spectroscopy in the experiments. This difference appears to increase with greater pulse energies. A parametric comparison of computational time for differences in laser pulse energy, constitutive models, and materials is also performed. Results reveal that the demonstrated model at the lowest pulse energy on alumina is up to 37.5% faster, and when applied to silicon carbide, is up to 15.7% faster in comparison to existing JH methods.

In this study, details of the rapidly evolving state of a laser impact welding (LIW) process are simulated by incorporating a hydrodynamic plasma pressure model into a high-fidelity thermomechanical Eulerian numerical approach. Detailed evolution of the localized velocities, shear stresses, plastic strains, and temperature state in the vicinity of the weld interface during its formation are revealed. The presented simulation technique applies a load distribution that is temporally and spatially modeled based on the plasma pressure induced during surface ablation by a nanosecond-pulsed infrared laser. Due to the Gaussian plasma-pressure loading profile, significant shear stress patterns are observed to develop in the flyer foil prior to its collision with the target foil, the character of which appears to be significant in achieving a successful impact weld. Moreover, features already known to be critical to successful impact welding of thin foils are captured by the combination of the high-fidelity Eulerian control volume and the plasma pressure model, including the requisite collision velocity and impact angle. During the impact welding, interfacial material ‘jetting’ is observed, in addition to concentrated shear stress fields along the weld front. A wavy interface arising from a regular pattern of material mixing is confirmed to occur, in addition to significant plastic strains and heat generation due to the plastic deformation, all of which indicate the formation of a collision joint due to the more realistic loading condition imposed.

A comparison is made between three different methods for fluid structure interaction (FSI) simulation of fused deposition modeled (FDM) nylon components having arbitrary internal cavity structures. The FSI methods studied include a simple fluid cavity (FC) model, a coupled Eulerian-Lagrangian (CEL) method, and a smoothed particle hydrodynamics (SPH) method. Model valuations are based on comparing the predicted macro compressive strengths for the simulated FDM builds with experimentally determined compressive yield strengths on actual FDM builds. Each simulation includes two Phases, where the first models the FDM build to compute thermal distortion and residual stresses. The second Phase applies the temperature distribution and state of stress from the first Phase as initial conditions, then includes an FSI simulation wherein the part undergoes quasi-static compression. It is found that the CEL and SPH methods demonstrate higher accuracy than FC, producing less than 2.5% and 1.06% errors, respectively, compared to the experiments. Considering computational demands, the results suggest SPH to be the most suitable method to capture the FSI effects. A case study illustrating generality of the approaches to a different FDM geometry is also included.

During laser impact welding, severe plastic strains and temperature spikes occurring in less than 1 µs make experimental observation impractical and necessitate computational modeling to characterize in-situ behavior. To understand the effects of microstructure and the associated inhomogeneity/anisotropy in laser impact welding, an Eulerian framework featuring aluminum 1100 flyer and stainless steel 304 target foils is applied to simulate cases with and without microstructure modeling. The transient thermomechanical phenomena revealed by the dynamic simulation provide insights into evolution of the in-situ structure-property relationship, including microstructural variation, phase transformation, and material jetting. In contrast to the homogeneous model, the inhomogeneous model suggests a 10 µm-thick zone of grain refinement at the weld interface establishing new grains 0.1-1 µm in diameter in the flyer, and causing partial martensitic phase transformation in the target, attributable to rapidly induced equivalent plastic strains of up to 10.71 in the flyer and 0.98 in the target.

This work investigates the coupling of inherent residual stress (IRS) and machining-induced residual stress (MIRS) on the final-state of residual stress (FRS) and distortion when high-speed machining (HSM) high aspect-ratio aluminum components. Motivation for this work stems from the simplifications in related numerical investigations that give rise to two limitations: First, the mapping of incompatible, incomplete, and/or spatially scarce IRS profiles generates unrealistic distortions and incorrect stress fields during static equilibration. Second, the simulation of machining via element deletion, inactive elements approach, or Boolean subtraction (removal) of material either ignores thermal and MIRS effects, or implements them based on simplified analytical/empirical models. Such practices therefore prevent a thorough understanding of how IRS and MIRS are coupled. Accordingly, two wrought aluminum 7050 blocks having different IRS profiles (based on stress relief) are considered in this work. An iterative stress reconstruction algorithm is implemented to numerically model a spatially-complete and fully-compatible IRS field in each aluminum block using limited data from slitting measurements documented in the literature. A 2D orthogonal cutting model is used to validate the material and damage models employed, as well as to elucidate the influences of IRS and MIRS on FRS. A 3D end milling model, which adopts the validated material and damage definitions, is then applied with different tool paths to reveal the coupled effects of IRS and MIRS on the distortion when HSM a C-channel featuring high aspect-ratio walls. The results reveal that the interaction between IRS and MIRS is nonlinear in nature, thus contrasting assumptions allowing for their superposition, as are widely reported and adopted in the literature. The results also show that the nonlinear coupling between IRS and MIRS varies according to both the component and location of stress within the machined part. Moreover, the findings reveal that the final part distortion is significantly influenced by the nonlinear coupling, as well as the specific machine tool path implemented.

Electrical energy consumption if reduced during peak hours can result in the deferment of generation, transmission and distribution capacity addition. The postponement of capacity addition, or “avoided cost” is of promising value to electric utilities who can redirect financial resources for other purposes due to these offset costs. The reduction in energy consumption is achievable through smart grid implementation. Therefore, the utilities need to investigate whether upgrading their grid system to make it smarter is economically justifiable or not. Electricity companies have used the smart grid maturity model to assess their rating/ranking in different domains. The paper provides a framework for establishing future strategies and work plans as they pertain to smart grid implementations. The objective of this paper is to evaluate the demand-side management (DSM), energy efficiency measures and distributed generation benefits of smart grid in Oman. The developed scenarios include grid enhancement, customer contribution to the grid and both of these options simultaneously. The scenarios are analyzed for peak reduction and their benefits are calculated in terms of avoided cost of generation, transmission, distribution, and environmental costs.

This work investigates the significance of microstructure-level modeling by simulating the material response of an inhomogeneous selective laser melted (SLM) Inconel 625 specimen subjected to two different post-process operations, namely micro-milling and laser shock peening (LSP). A physics-based thermal finite element simulation is executed to obtain the SLM thermal history from which a 3-dimensional inhomogeneous microstructure representative volume element (RVE) is generated via the Dynamic Kinetic Monte Carlo predictive model. A Johnson–Cook plasticity definition coupled with Hall–Petch strengthening is used to define unique yield surfaces for individual grains based on their major diameters. Micro-milling and LSP simulations are subsequently executed with and without considering an inhomogeneous microstructure RVE in attempt to elucidate differences in the plastic strain, temperature, induced stress magnitude and distribution, as well as differences that arise during material removal for the micro-milling only. The micro-milling simulations reveal a greater volumetric distribution of plastic strain and temperature for the inhomogeneous case, although the homogeneous case with isotropic assumption reveals greater heat dissipation at the tool-workpiece interface with 27% greater contact pressure and 39% greater frictional shear stress. Examining the ductile and shear damage progression at a specific time increment reveals that the inhomogeneous model has a slightly lower damage propensity in comparison the homogeneous case, despite having identical damage models and boundary conditions. Variation in the SLM process-dependent yield surfaces, for grains at different locations, results in spatial variations of the computed stress triaxiality, which influences the material removal, as well as the stress concentrations developed near the tool-workpiece interface. Thus, a process-structure-property relationship is captured with the microstructure modeling. This work is the first to illuminate the importance of capturing SLM-induced anisotropy, considering the additively manufactured grain structure subject to micro-milling and LSP post-processes.

This work represents the first investigation into the influence of residual stress (RS) from powder-based metal additive manufacturing (AM) on the post-process machining-induced stress and distortion for thin-walled components. Machined part distortion and surface residual stress pose major challenges in several industries, including for aerospace applications involving monolithic structures. However, the influence of initial RS in the bulk material on high-speed machining-induced stress and distortion is still not well understood. This is particularly true for more recent hybrid (additive and subtractive) manufactured components in which significant tensile and compressive RS develops from the rapid thermal cycles during the AM build. It is hypothesized in this work that, even for a simple thin-walled structure, the initial RS in the AM bulk material significantly influences the RS and distortion induced by high-speed machining. It is further hypothesized that the degree of influence of the initial RS on machining-induced RS and distortion varies significantly according to the specific tool path, even for the same net material removal. To test these hypotheses, a numerical modeling approach is presented considering a thin-walled directed energy deposition (DED) structure subjected to high-speed end-milling. A compatible RS field for the DED build is established using an iterative reconstruction algorithm based on limited neutron diffraction measurements, and the full reconstructed RS field is then imposed as an initial state in the end-milling simulation that follows. To assess the influence of the initial DED RS on the machining-induced stress and distortion, as well as to examine how this influence varies with machining strategy, two different tool paths are considered for the same net material removal, both with and without considering RS inherent to the DED build. The findings reveal significant influence of the DED RS on the high-speed machining-induced distortion and RS, and further, this influence is seen to vary greatly with the machining strategy. Normalized root-mean-square differences (NRMSD) of up to 25 % and 29 % , respectively, are observed in the machining-induced RS for the two different tool paths when DED inherent RS is considered. Likewise, maximum NRMSD of up to 44 % and 40 % are revealed in the post-machining distortion for the two respective machining strategies when DED RS is included. In addition, variations observed in the stress triaxiality computed during machining suggests that inclusion of the DED RS influences the localized response of the material near the tool-workpiece interface. The technical approach demonstrated can be extended beyond hybrid manufacturing to generate important scientific insights regarding distortion and machining-induced stress for conventionally manufactured monolithic components in the aerospace and other performance-critical industries.

In this work, laser shock peening (or simply laser peening) is investigated for the first time as a post welding treatment for dissimilar foils joined via the fully-mechanical, high-velocity laser impact welding technique. Single and double laser peening shots were applied to laser-impact-welded foils using three different metallic material combinations. Subsequent lap shear testing showed that single-shot laser peening increased the average weld strength by 12% to 25%, depending on the flyer and target material combination. In contrast, with double-shot laser peening, the average weld strength decreased regardless of the flyer and target materials involved. Scanning electron microscope images revealed wavy weld interfaces and increased interlocking between the foils for the single-shot laser peening treatments as compared to the initial “flat” weld interface geometry, thereby leading to greater flyer/target weld strength. In the double-shot laser peening treatments, however, separations and melting were observed along the weld interface due to rebounding and excessive plastic heat dissipation of the foils. The findings of this study reveal the first insights and effects regarding the application of laser shock peening as a post-welding treatment beyond conventional fusion-based welding to high-velocity impact welding methods.

Despite the proliferation of cellular fused filament fabrication (FFF) polymer components for a variety of industrial applications, few studies have investigated their fluid–structure interaction (FSI) behavior during loading, particularly under dynamic impact conditions. Furthermore, the extent to which residual stresses from the FFF build process affect the dynamic load bearing characteristics has not been addressed. In this work, simulations and experiments are conducted for cylindrical nylon specimens fabricated with two different internal closed-cell cavity structures to assess the influence of the entrapped fluid and the FFF residual stresses on the state of stress during high strain-rate impact. The demonstrated 2-stage computational approach includes a thermomechanical model of the FFF build to calculate residual stress and distortion, which forms the initial state for a subsequently executed dynamic impact model using smoothed particle hydrodynamics (SPH) to capture the effects of air within the internal cavities. Dynamic displacement boundary conditions for the FSI simulations are identified using digital image correlation (DIC), obtained from impact experiments on the FFF specimens performed using split Hopkinson pressure bar (SHPB) tests. Findings reveal that FFF residual stresses significantly influence the stress–strain response during dynamic impact, even at strain rates of 500–600 s−1. In addition, while the influences of both FFF residual stress and FSI vary with internal cellular structure, the study reveals that their coupled effects must be considered to accurately characterize the impact behavior. Validity of the 2-stage numerical approach, as well as significance of FFF residual stress and the influence of FSI, are justified by comparing numerical predictions with experimental measurements, and observing root-mean-square stress errors within 12.77% and 11.87%, and peak stress errors within 1.93% and 1.34% for the two specimens.

Introduced is a comprehensive numerical modeling framework that includes microstructure when simulating the laser impact welding (LIW) of metals to study the transient phenomena that occur during weld formation. Such transient phenomena include evolution of shear stresses, plastic strains, thermal response, and material jetting. Inhomogeneous microstructures for two dissimilar foils (aluminum 1100 and stainless steel 304) are first predicted using the Dynamic Kinetic Monte Carlo (KMC) method to simulate laser-based powder bed fusion (PBF-LB) additive manufacturing (AM). These microstructures are subsequently incorporated into an Eulerian finite element (FE) simulation of the LIW process, enabling prediction of grain elongations that result from the varying yield surfaces, stacking fault energies, and grain-boundary sliding effects. Trends in the predicted microstructure deformation patterns show strong agreement with those from experimental images in the literature. Compared to existing homogeneous models, the new framework with inhomogeneous AM microstructure reveals higher collision velocities at the weld interface, resulting in increased plastic strain rates, greater plastic heat dissipation, and increased material jetting with higher jet temperatures. The framework allows for new opportunities to study correlations between grain topography (as well as polycrystalline metal texture) and the transient process phenomena occurring at the impact weld interface.

This work describes a Dynamic Kinetic Monte Carlo numerical modeling framework that can predict the microstructure of metals during powder bed fusion (PBF) and directed energy deposition (DED) additive manufacturing (AM) while considering significant variations in thermal history and heat accumulation that occur during the build. Although the conventional Kinetic Monte Carlo (KMC) method is well-established, it does not accommodate variation in the spatial domains of the melt pool (MP) and heat affected zone (HAZ) with time. Thus, the predicted microstructure remains relatively similar even over large AM build domains. While the existing KMC approach may suffice over spatial regions in which the MP and HAZ remain relatively unchanged, this circumstance is largely contrary to what experimentalists have recently found when imaging different regions in PBF and DED AM builds, thus raising issues with scalability and versatility of the method. The Dynamic KMC framework proposed in this work addresses these concerns by implementing discretized, spatially-varying MP and HAZ at every time increment during the grain structure prediction. The new framework operates in two stages; stage one establishes the 3D spatial MP and HAZ dimensions using either thermal finite element (FE) simulation or through experimental 3D thermal imaging; stage two subsequently integrates these time-varying MP and HAZ dimensions into the KMC algorithm at every time increment during the build. Thus, the Dynamic KMC framework captures the effects that rapid thermal cycles and heat accumulation have on grain nucleation and growth. The method is demonstrated through a case study involving a thin-walled Inconel 625 structure made by the selective laser melting (SLM) type of laser-based powder bed fusion (PBF-LB). The numerically predicted microstructures at various regions and scan layers within the build show strong agreement with experimentally observed trends reported in literature. Significant variations in grain morphology predicted by the Dynamic KMC framework can, according to specific thermal histories, provide investigators with new capabilities in assessing mechanical property variations across different regions of AM parts.

With increased demand for thin gage flat metals, control of strip flatness or shape in cold rolling processes has become very important. To improve the flatness quality of cold rolled metal strip and sheet, this work provides a rapid method to predict the transient strains (or stresses) occurring during the rewinding of flat-rolled steels having problematic asymmetric strip thickness profile (or wedge). Flatness control systems, used to monitor and correct the distribution of stress across the width of rolled sheet, are unable to distinguish between stresses induced during rolling, and those caused when rewinding strip containing asymmetric thickness profile. The winding stresses, unless large enough to plastically deform the strip, vanish upon unwinding during subsequent operations such as stamping. Therefore, to help avoid strip flatness defects in thin strip containing wedge, a method is developed to separate the winding stress contribution from the overall stresses that are measured indirectly by flatness control systems. A fourth-order polynomial Airy function is developed to rapidly predict the in-plane stresses based on mandrel wrap number and spatial location on the strip. The Airy function is obtained by applying two-dimensional finite element analysis to study the transient in-plane stresses during rewinding at various numbers of mandrel wraps for a strip containing wedge profile. Three-dimensional finite element analysis is first employed, however, to show justification to a simplified two-dimensional problem described by the plane-stress Airy function. The two-dimensional finite element analysis provides insight as to how the in-plane stresses evolve, and allows determination of coefficients for the Airy function based upon model geometry and displacement boundary conditions. This approach differs from other methods that employ Fourier series to solve the biharmonic equations for an assumed two-dimensional problem. Finally, filtering of the winding stresses from flatness control system input signals is also discussed based on data taken from a rolling mill different to that used for model development.

Solar and wind energies are likely to play an important role in the future energy generation in Oman. This paper utilizes average daily global solar radiation and sunshine duration data of 25 locations in Oman to study the economic prospects of solar energy. The study considers a solar PV power plant of 5-MW at each of the 25 locations. The global solar radiation varies between slightly greater than 4 kWh/m 2 /day at Sur to about 6 kWh/m 2 /day at Marmul while the average value in the 25 locations is more than 5 kWh/m 2 /day. The results show that the renewable energy produced each year from the PV power plant varies between 9000 MWh at Marmul and 6200 MWh at Sur while the mean value is 7700 MWh of all the 25 locations. The capacity factor of PV plant varies between 20% and 14% and the cost of electricity varies between 210 US$/MWh and 304 US$/MWh for the best location to the least attractive location, respectively. The study has also found that the PV energy at the best location is competitive with diesel generation without including the externality costs of diesel. Renewable energy support policies that can be implemented in Oman are also discussed.

Oman relies on gas and oil resources fuels for almost all of its energy needs. Almost 99% of its power generation is based on natural gas. However, the country's natural gas supplies are currently largely committed, and it may become a net importer soon. Therefore, there is a need to look for alternative energy resources. This paper presents a review of the assessed potential of renewable resources and practical limitations to their considerable use in the perspective of present scenarios and future projections of the national energy for Oman. Solar and wind are likely to play an important role in the future energy in Oman provided that clear policies are established by the higher authority for using renewable energy resources. Rural Areas Electric Company has initiated solar and wind pilot projects in its concession area to confirm the performance and efficiency of renewable technologies in local conditions.

In December 1999 the council of Ministers of Sultanate of Oman approved policies for the wholesale restructuring and privatization of the sultanate's electricity and related water sectors. The government started carrying out unbundling of the sector and setting up independent companies on a commercial basis. The companies are now shaping up for future electricity market. Beside these evolving structural changes, there would be a need to change their generation mix. Oman relies 100% on fossil fuel resources (mainly gas) for its power generation. However, Oman's natural gas supplies are largely committed and the country may become a net natural gas importer in the near future. Today, there is a great incentive for Oman to exploit renewable energy in order to face the changing environment and to guard against future trends. The electricity companies should investigate the renewable potential and work with Omani government and Authority for Electricity Regulation (AER) to establish policy support for large-scale renewable energy plants. Beside there is a huge potential for demand-side management and energy conservation which should be exploited for the benefit of the country and of the environment.

This paper presents a study carried out to investigate the economics of wind turbine as an energy fuel saver. The load and the wind data is taken from a remote agricultural research station in Oman. Presently, the station is provided with electricity from diesel-engine generating units. The annual peak load and minimum load recorded at the site is 130 kW and 28 kW respectively. The annual average wind speed at the site is 5.7 m/s. A 50-kW wind turbine is selected to demonstrate the economic feasibility of the turbine as a fuel saver. The results show that wind energy utilization is an attractive option with total specific cost of the selected wind turbine ranges between 7.4 and 8.45 ¢/kWh at 7.55% discount rate comparing to diesel generation operating cost of 14.3 ¢/kWh, considering the capital cost of diesel units as sunk. The simple payback period of the turbine is between 5.1 and 5.4 years and discounted payback between 6.7 and 8.0 years.

Given Algerian’s abundant solar, wind resources, biomass, geothermal, etc. represent a potential market for renewable energy technologies. This article presents a review and the use of renewable energy situation in Algeria. The analysis of the present renewable energy situation and future objective are also discussed.

Presented is a new computational method for predicting the static cross-sectional thickness profile of rolled metal strip. Methods to model the strip profile and related flatness with improved efficiency and accuracy remain central for achieving high quality flat-rolled products. The new method involves a novel combination of Timoshenko beam finite elements with multiple coupled Winkler elastic foundations. It applies to simple mill configurations, such as the common 4-high rolling mill, in addition to complex mill types, such as the 20-high Sendzimir mill. The inherent benefits over traditional strip profile models include non-discrete elastic foundations, cubic displacement fields, rapid solution, and mixed boundary conditions. The flexible nature of the model allows it to readily accommodate typical mechanisms used in industry to control strip profile, such as roll crowning, roll bending, roll shifting, and roll crossing. Comparison of the predicted displacement for a 4-high mill with that obtained using a large-scale finite element simulation provides validation of the presented strip profile calculation method for real-time industrial applications.

This paper presents the results of a study that estimated the DSM energy saving and load management potential in commercial and government/institutional sectors in Oman (central grid area) and evaluated its impact on generation capacity and energy savings. The end-use (lighting and air-conditioning) energy consumption data have been collected in two major segments of the commercial sector for simplicity and to save time and money. Another unique aspect of the study is the inclusion of the energy savings, in transmission and distribution (T&D) losses that are estimated by using generation expansion planning approach. The study has found that DSM is financially beneficial from customers’ point of view as the discounted payback period of investment in efficient lighting and air-conditioning is between 4 and 12 years of the surveyed sample. From the utility point of view the capacity saving at the horizon year is between 372 and 596 MW and the overall energy saving for the whole planning horizon is about 29–44 TWh. The total avoided cost in generation and capacity saving is somewhere between 416 and 597 million dollars.

The electricity tariffs in Oman are subsidized and are based on a cost accounting approach and do not reflect the true cost incurred in generating, transmitting and distributing a kilowatt-hour of electricity at the consumer end. This paper presents the electricity tariff based on the estimation of long-run marginal cost at generation, 33 kV, and 415 voltage level for Ministry of Housing, Electricity & Water (MHEW) interconnected power system of Oman. The result shows that at the generation level a marginal kW costs US$ 75 per year and a marginal kWh costs 2.07 ¢/kWh. These costs increase as we move downstream from generation to consumer end. The average cost of electricity at the consumer end connected at 415 V is 6.52 ¢/kWh or 25.17 Bz/kWh.

This paper extends the application of probabilistic peak-shaving technique used for simulating limited-energy units, LEUs, probabilistically within the framework of equivalent load duration curve, ELDC method. The extension of the application is within the framework of frequency and duration, FD, method. The technique proposed is independent of the ELDC and FD representations. The application of the technique is demonstrated with the help of a hand calculation example. An efficient algorithm is also presented to simulate multiple LEUs probabilistically, for different hydrological conditions, in a generation mix of hydrothermal units within ELDC and FD framework. The algorithm overcomes the ordering problem of LEUs and requires no deconvolutions of ELDCs and load transition frequency equations.

A feeder-specific expansion investment plan of a distribution utility is analyzed for exploiting demand-side resource options using feeder- and time-specific marginal costs. The study found that with a utility-led demand-side management program where the utility shoulders the up-front capital and administrative costs while benefits are equally shared between the utility and participating customers, idle customer-owned standby diesel generating sets together with efficient cooling and lighting technologies appear as a viable options to meet current and projected demand. Demand-side resources prioritization based on their impact to monetary and non-monetary criteria (reliability, voltage quality and environmental) is accomplished with analytic hierarchy process (AHP) approach. The customers' perception to each of the given decision criteria are solicited through customer survey.

This paper reports the results of a local integrated resource planning (LIRP) study conducted for the Philippines. Based on the investment plans for serving loads at distribution feeders our key finding is that distributed resources (DR) are cost effective alternatives to supply capacity expansion for Cagayan Electric Power and Light Co. (CEPALCO), an investor-owned power distribution utility company operating in the Southern Philippines. The total cost savings for the selected feeder on which LIRP was performed are about 19 million Pesos (about half a million US dollars, 1998) over a 10-year period.

This paper presents a technique to model demand-side management programs into production costing analyses within the framework of equivalent load duration curve and frequency and duration method. The technique allows a single simulation to study probabilistically the impact of DSM on loss-of-load probability, energy not served, energy consumption and cycling costs of power plants. Also the importance of incorporating the cycling costs of power plants in the cost-effectiveness analysis of DSM programs is presented. Comparable results are achieved when the technique is tested against the avoided cost method of two simulations by applying them to IEEE RTS data. The results also reveal that avoided start-up cost is a major benefit of DSM. The applicability of the paper is relevant to vertically integrated utilities.

This paper presents a methodology based on an equivalent load duration curve (ELDC) and frequency and duration approaches to assess the economic benefits of demand-side management (DSM) load impact in terms of avoided energy production costs and avoided start-up and shut-down (cycling) costs of thermal units. The proposed method is applied to IEEE reliable test system (RTS) data to assess the benefits of DSM load impacts. The sensitivity of avoided energy cost and avoided cycling cost is calculated with a varying generating capacity reserve margin in the system. From a utility point of view, the loss of revenue due to DSM measures is also worked out with certain assumptions and sensitivity of the revenue loss due to DSM actions is again tested with a different generating capacity reserve margin in the system. The study finds that the avoided cycling cost is a major benefit of DSM measures. The study also finds that the real revenue loss is far less than the apparent revenue loss seen by the utility as the benefit of reduction in start-up and shut-down costs is not realised in the loss of revenue calculations.

This paper deals with cost savings resulting from DSM, i.e. reductions in the number and cost of shut-downs and start-ups of generators. The proposed methodology applied to a test-data system yields savings of 28%. The total avoided costs are also estimated and it is pointed out on the basis of a total resource cost that the omission of these dynamic benefits can result in a bias against a DSM program and may lead to a wrong policy decision.