Ramp-up Rate Research Articles

Enhancing the load ramp-up capability of the subcritical CFB power unit by considering the evolution of internal stored energy

The substantial inertia of the boiler restricts the flexibility of circulating fluidized bed (CFB) power units. To enhance the load ramp-up capability of the CFB power unit, we proposed a novel control strategy considering the spatial-temporal evolution of its internal stored energy. A dynamic model of the subcritical CFB power unit with a capacity of 300 MW was developed, incorporating the mechanism and control modules. By analyzing the spatial-temporal evolution of the stored energy in bed material, flue gases, refractory materials, economizer, evaporation subsystem, superheater subsystem, reheater subsystem, and turbine subsystem, we identified that the over-utilization of chemical and thermal stored energy in the bed materials is the primary factor restricting load ramp-up, while the thermal stored energy of the economizer is suitable for further utilization. Under the optimized control strategy that utilizes deviations of stored energy per mass of bed materials as a feedforward mechanism, the deviations of the key operating parameters during the load ramp-up process are significantly reduced, and the load ramp-up rate of the subcritical CFB power unit can be improved from 2.0 % Pe/min to 3.0 % Pe/min.

Benchmarking study of coal seam gas production from Brownfield to Greenfield wells in the Surat basin, Australia

Benchmarking coal seam gas (CSG) production from Brownfield to Greenfield is an important step for assessing the development plan for Greenfield. However, the observed Brownfield production data is impacted by many factors besides reservoir properties, e.g., well spacing, well efficiency factor (WEFAC), surface pipeline network. This paper presents a case study in the Surat Basin to discuss how to benchmark CSG production from Brownfield to Greenfield. The selected Brownfield study area includes 143 wells and the Greenfield 450 proposed wells. Various tools for static modelling, decline curve analysis, and dynamic modelling were used in this study. Results show that the peak gas rate decreases quickly and the time to peak gas rate increases quickly when the WEFAC is less than 0.65. The peak gas rate is reached when the cumulative water production is between 39% and 46% of water-in-place for the selected box model. After introducing the wells’ online time ratio or WEFAC from the daily production data and the ratio of the observed cumulative water production to the expected cumulative water production, gas production rates can be predicted based on the modified Morse potential energy equation. Artificial neural networks (ANN) can be used to estimate the peak gas rate, the time to peak gas rate and the decline rate based on the reservoir properties; while the ramp-up rate can be calculated from the time to peak gas rate.

Control of supercritical CO2 Brayton cycle for fast and efficient load variation processes

The supercritical carbon dioxide (S-CO2) cycle is considered a promising power conversion system due to its high efficiency and flexibility. This work presents a dynamic model of a 600 MWe S-CO2 recompression Brayton cycle (RBC) and validates it at both component and system levels. To ensure the safety and stability of the S-CO2 RBC during wide-load operation, some necessary control strategies are designed, including minimum pressure and temperature control, split ratio control, turbine inlet temperature control, and anti-surge control. Moreover, an innovative valve-inventory joint control method is proposed, coupled with an improved inventory tank layout, to achieve both fast and efficient load variation processes. Compared to the control strategy before improvement, the ramp-up and ramp-down rates are significantly increased by 2.65 and 2.24 times, respectively. In addition, the values of key parameters suitable for wide-load operation of the S-CO2 RBC are determined to maximize the cycle efficiency under off-design conditions. The results show that the split ratio should be dynamically adjusted to determine the optimal value that varies with the load, which can improve the cycle efficiency by a maximum of 1.13 %. Finally, the dynamic performance of the S-CO2 RBC is studied during load ramp changes and real-time microgrid load, and the variations in heat exchange, pressure, temperature, and mass flow rate of key components are revealed. Comparative analysis with previous literature demonstrates that the proposed control method provides a wider load regulation range, an increase of 7.78 % in cycle efficiency, and a reduced maximum generation frequency deviation of 0.696 Hz. There is no overpressure or compressor surge risk, and the maximum temperature change rate is only 1.3 ℃·min−1.

Soft H-L back transitions by applying resonant magnetic perturbations in the low q 95 EAST plasmas

Controlled ‘soft’ H-L transitions with a simultaneous ramp-down of plasma density and stored energy, generated by applying resonant magnetic perturbations (n = 2 RMPs), relevant to the control of ITER terminations, are achieved in the EAST tokamak. These H-mode plasmas are run at median electron densities and a low safety factor q 95 ( q95=3.5 –4.0) under neutral beam injection (NBI) dominant heating. During a slow ramp in the RMP current the internal transport barrier for the electron density collapses at the beginning and the edge transport barrier for the electron density collapses later. Before the controlled H-L back transitions, the plasma stored energy W MHD is linearly correlated with the core line-averaged density ⟨ne⟩ . These controlled H-L back transitions ensue from the collapse of the edge transport barrier and at a similar energy confinement time τeH-L∼48 ms. These H-L transitions are not sensitive to the NBI power but are very sensitive to the fueling rate and ramp-up rate of the RMP current.

Power augmentation and Ramp-Up rate improvement through compressed air Injection: A dry low NOx combustor CFD analysis

Gas turbines play a key role in accelerating the transition towards more environmentally friendly power generation. This role includes backup of renewable generation that is intermittent, providing grid inertia as well as other ancillary services for grid stability. For quick backup power, the ramp-up rate of gas turbines can be improved through air injection at the back of the compressor, facilitated by integrating compressed air energy storage. Published works have mostly focused on low-fidelity engine system analysis of air injection overall effects. No study has focused on the detailed combustor performance presented in this study. The work shows the impact of air injection on the emissions, thermoacoustic stability and liner wall durability. These yardsticks in assessing the operability of the combustor have also been used for air power augmentation and ramp-up analysis. ANSYS software was used in the computational fluid dynamics (CFD) analysis of the three-dimensional dry low NOx combustor. Low-order models were used for the thermoacoustic stability and durability analysis. For the power augmentation study, the NO and CO emissions produced at 15 % air injection are below the maximum values of the combustor in design operations. Also, the stability and durability were within limits. The ramp-up investigation indicates up to 10 % air injection is allowed and the emissions are similarly acceptable. However, the thermoacoustic analysis shows a potential for combustion instabilities at high frequencies above 1800 Hz. Generally, there was no unusual wall liner durability in these two studies. When benchmarked against previous engine-level analysis, the ramp-up rate can be potentially improved by 54 % if the small concern on thermoacoustic instability is resolved.

Enhancing the flexibility and stability of coal-fired power plants by optimizing control schemes of throttling high-pressure extraction steam

Regulating the thermal system configuration can improve the ramp-up rate of the coal-fired power plants during peak shaving transient processes, while it may bring penalties in the performance of the steam temperature control and thermal efficiency. This study simulated the load ramping up transient processes when throttling the extraction steam of high-pressure heaters. The results show that there is a gap between the needed energy and energy supply caused by drastic fluctuations of reheat steam flowrate. Control schemes of steam temperatures and fuel demands were revised considering the dispatch of the fuel and working medium. According to economic optimality, the order of throttling high-pressure heaters was optimized. By implementing the revised control strategies, the fluctuations of steam temperatures were diminished and the maximum deviation of live and reheat steam temperatures was reduced by 23.5 °C and 11.4 °C, respectively. The flexibility indicator was increased by up to double at most. The average standard coal consumption rate variations with and without the revised control schemes were compared and the maximum difference is 1.23 g kW−1 h−1 with 2.5 % Pe min−1. The flexibility and economic performance were both improved when adopting the revised control schemes.

Atomically dispersed high-loading Pt-Fe/C metal-atom foam catalyst for oxygen reduction in fuel cells

Designing efficient and stable single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) is essential to promote fuel cell commercialization. In this study, the Bayesian Regularization Neural Network (BRNN) has been used to determine the carbothermal shock (CTS) conditions for preparing high-loading Pt-Fe/C SACs. The BRNN model effectively identified a low reaction temperature of 283 °C for achieving high-loading (15 wt %) Pt-Fe/C SACs. Based on this model, we successfully synthesized Pt-Fe/C SACs with a metal mass content of 11.31 wt % using the CTS method. These ultrahigh content metal Pt-Fe/C SACs consisted of dispersed single atoms and foam-like atomic constructions, namely Pt-Fe/C atom foam catalysts (AFCs), rendered them promising candidates for electrocatalysis applications. The Pt-Fe/C AFCs exhibited good catalytic activity and durability toward ORR in alkaline conditions. The Pt-Fe/C AFCs were employed in a direct borohydride fuel cell (DBFC) as cathode catalyst, which resulted in a maximum power density of 214 mW cm−2 at 60 °C and demonstrated stable discharge for 40 h at room temperature. The electrocatalytic performance of the Pt-Fe/C AFCs surpassed that of low-loading Pt-Fe/C SACs and commercial Pt/C catalysts. The rapid ramp-up rate and the rapid cooling rate of the CTS process enabled the incorporation of high-loading Pt and Fe metal atoms into the graphitized carbon layer, resulting in an increased number of active sites of the Pt-Fe/C AFCs. This work provides an effective strategy for manufacturing efficient and stable SACs for practical applications in fuel cells.

Design and Manufacture of a Test Cryostat With MgB2 Superconducting Magnet Significantly Reducing Helium Consumption

A test cryostat equipped with a conduction-cooled MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> high-temperature superconducting bias magnet has been designed, manufactured, and demonstrated. This cryostat is more environmental-friendly and user-friendly than the conventional cryostat with an immersion-cooled NbTi superconducting magnet. Liquid helium consumption is reduced by almost half of that of a previous conventional cryostat because the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet does not need liquid helium for cooling itself. A ramp-up rate of the bias magnet has also been improved to 1 A/s, which is almost 10 times faster than that of the previous NbTi magnet, due to the high stability of the superconducting MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet. A maximum bias magnetic field is 1 T at the center of the magnet. A helium vessel of the cryostat is 212 mm in inner diameter so that various superconducting samples such as bulks, short samples of wires, and small coils, could be immersion-cooled by cryogen and tested in it. A performance demonstration was also successfully conducted.

Batch Process Operational Effects on Phosphorus Attainment in Hydrochar Produced by Hydrothermal Carbonization of Dairy Manure

Highlights Temperature ramp-up from 180°C to the pre-set processing temperature significantly affects total phosphorus attainment rate. The transition time of temperature ramp-up is crucial in assessing the change of TP attainment rate. Temperature cooling does not show significant effect on total phosphorus attainment rate. Abstract. As an alternative technology for phosphorus cycling, hydrochar produced from animal manure is a great vehicle to attain phosphorus from dairy manure and apply it back to cropland in an environmentally friendly manner. Hydrochar production by hydrothermal carbonization (HTC) greatly reduces the time to manage animal manure compared to traditional lagoon systems. Before being established as a practical technology for hydrochar production in continuous-flow operations, HTC in batch mode is the best way to systematically investigate and optimize the process conditions for high efficiencies. This study investigates specifically the effect of temperature ramp-up rates on the attainment of total phosphorus (TP) in hydrochar produced from dairy manure through batch-mode HTC operations. Experimental results revealed that the transition in temperature ramp-up greatly affected the TP attainment rate in hydrochar, depending on the pre-set processing temperatures and holding time. Statistical analysis confirms that such an effect is significant if the holding time is 30 min or less. This is due not only to the higher processing temperatures but also to the extra 5 to 15 minutes of processing time required for the ramp-up to the pre-set temperatures of 195°C to 255°C, at which point biomass decomposition has already occurred. It is concluded that the temperature ramp-up in batch HTC processes significantly affect the TP attainment rate in hydrochar produced from dairy manure. Before developing continuous-flow HTC systems, it is recommended that experimental results from batch operations be carefully interpreted. Keywords: Batch processes, Dairy manure, Hydrochar, Hydrothermal carbonization, Phosphorus.

입자가속기용 초전도 코일 개발을 위한 절연설계법 개발

High-temperature superconductor (HTS) can be applied to manufacture superconducting coils for particle accelerators. Since HTS has a larger heat capacity than low-temperature superconductor (LTS), HTS is suitable for developing particle accelerators with fast ramp-up rate. A superconducting coil using HTS can be miniaturized with a fast ramp-up rate, thereby obtaining economic benefits such as reduction in maintenance and repair costs. High electric field intensity may be induced at a superconducting coil such as a saddle coil for medical accelerators owing to its complex structure. It is known that the dielectric performance of electrode systems can be poor in the medium vacuum range. In this study, dielectric experiments for establishing empirical formula to design a reliable HTS coil against fast ramp-up rate in various vacuum conditions were performed. As a result, empirical formula to design an electrically stable HTS coil were deduced through dielectric experiments with various conditions considering pressure, electrode size, and gap between electrodes.

Effect of Situation Kinematics on Drivers’ Rear-End Collision Avoidance Behaviour—A Combined Effect of Visual Looming, Speed, and Distance Analysis

Considering the large proportion of rear-end collisions occurring in our daily life and the severity it may lead to, the objective of this study was to investigate the effect of situation kinematics on drivers’ rear-end collision avoidance behaviour after brake onset. A wide range of lead vehicle deceleration scenarios were designed based on driving simulator experiments to collect drivers’ deceleration behaviour data. Different from measures (e.g., speed, the lead vehicle’s deceleration et al.) often adopted in previous studies, a visual looming-based measure at different time points was calculated combined with analysis of speed and distance to quantify situation kinematics in this study. The Spearman’s nonparametric rank correlation test was firstly conducted to examine the correlation between visual looming-based metrics and related deceleration behaviour. The mixed model was performed on drivers’ brake jerk and maximum deceleration rate, while the logistic model was then performed to predict the probability of the occurrence of rear-end collisions. Spearman’s nonparametric test showed that both deceleration ramp-up and drivers’ maximum deceleration rate increase significantly as the looming traces increase faster. Results of the logistic model indicated that the probability of occurrence of a potential collision might be higher if the situation at the brake onset is quite urgent and braking is moderate. It was demonstrated that both drivers’ deceleration ramp-up and maximum deceleration rate could be highly kinematic-dependent, and visual looming, driving speed, and distance can be useful information for drivers to take relative deceleration actions.

Energy dissipation during magnetic reconnection in the Keda linear magnetized plasma device

This paper investigates energy dissipation during electron-scale magnetic reconnection with laboratory experiments. Magnetic fields with opposite directions are generated by two parallel identical pulsed currents in our Keda linear magnetized plasma device. Magnetic reconnection is realized in the rising phase of the pulsed currents. The ramp-up rate of the pulsed current is found to be proportional to the inflow speed, providing a method to modify the reconnection drive. The incoming magnetic energy and its dissipation into plasma energy have been estimated in the vicinity of the X line. It is found that the plasma energy converted from the incoming electromagnetic energy increases with the increasing reconnection drive, while the conversion ratio remains almost unchanged, which is about 10%.

Methane Single Cell Protein: Potential to Secure a Global Protein Supply Against Catastrophic Food Shocks.

Global catastrophes such as a supervolcanic eruption, asteroid impact, or nuclear winter could cause global agricultural collapse due to reduced sunlight reaching the Earth’s surface. The human civilization’s food production system is unprepared to respond to such events, but methane single cell protein (SCP) could be a key part of the solution. Current preparedness centers around food stockpiling, an excessively expensive solution given that an abrupt sunlight reduction scenario (ASRS) could hamper conventional agriculture for 5–10 years. Instead, it is more cost-effective to consider resilient food production techniques requiring little to no sunlight. This study analyses the potential of SCP produced from methane (natural gas and biogas) as a resilient food source for global catastrophic food shocks from ASRS. The following are quantified: global production potential of methane SCP, capital costs, material and energy requirements, ramp-up rates, and retail prices. In addition, potential bottlenecks for fast deployment are considered. While providing a more valuable, protein-rich product than its alternatives, the production capacity could be slower to ramp up. Based on 24/7 construction of facilities, 7%–11% of the global protein requirements could be fulfilled at the end of the first year. Despite significant remaining uncertainties, methane SCP shows significant potential to prevent global protein starvation during an ASRS at an affordable price—US$3–5/kg dry.

Aerodynamic limits air injection for heavy-duty gas turbine: Compressor aerodynamic limits for power augmentation and ramp-up capabilities

Improved operational flexibility of gas turbines can play a major role in stabilising the electric power grid, by backing up intermittent renewable power. Gas turbines offer on-demand power and fast dispatch of power that is vital when renewable power reduces. This has brought about increasing demand to improve the ramp-up rate of gas turbines. One approach is through the injection of compressed air from energy storage or an auxiliary compressor. This method is the focus of the present work, which shows for the first time, the implications and limits of compressor air injection in a high-fidelity Computational Fluid Dynamics model (CFD). The 3D multi-stage model of the compressor was developed in ANSYS CFX v19.2, while the boundary conditions related to the injection cases have been obtained from a corresponding 0D engine model. The upper limits to air injection determine how much air can be injected into the engine, providing indicative values of power augmentation and ramp-up rate capabilities. These have been previously addressed by the authors using 0D models that do not consider the compressor aerodynamics in great detail. The CFD study has shown that for power augmentation, 16% of compressed air (based on compressor exit) is allowed based on the onset of stall. It also shows that increasing air injection amplifies losses, blockage factor and absolute velocity angle. Also, about 30% of the blade span from the hub is dominated by a rise in the total pressure loss coefficient, except the outlet guide vane for which separation occurs at the tip. For the ramp-up rate analysis, up to 10% air injection is shown to be sustainable. The work shows that the improvements in the 0D analytical engine model are plausible, in addition to demonstrating similar limits at different ambient temperatures.

Numerical Modeling of the Steam Chamber Ramp-Up Phase in Steam-Assisted Gravity Drainage

Due to the critical nature of the ramp-up phase of an efficient steam-assisted gravity drainage (SAGD) process, it is important to understand the physics of the steam chamber ramp-up phase in order to improve SAGD production performance. In conventional numerical simulation models, the dynamics of the steam chamber ramp-up phase are not fully resolved because of unclear steam–oil–water interactions during the vertical growth of the steam chamber and how its state changes as the reservoir parameters vary. This work provides an efficient approach for the numerical modeling of the steam chamber ramp-up phase in an SAGD operation. The steam chamber ramp-up phase was fully examined through the consideration of the effects of the temperature-dependent oil–water–gas multiphase flow system and the vertical countercurrent flow. The simulation results revealed that for the large temperature gradient of the mobile oil zone at the edge of the steam chamber, a delicate temperature-dependent multiphase flow system was essential for the reliable estimation of the SAGD ramp-up phase. The vertical countercurrent flows of oil–gas and oil–condensate were the dominant mechanisms over cocurrent flow, which significantly impacted the steam chamber ramp-up rate. The numerical model physically predicted the steam chamber ramp-up phase and could be used to efficiently compute a field-scale simulation using a dynamic gridding function that was based on a fine grid model.

Synthetic fat from petroleum as a resilient food for global catastrophes: Preliminary techno-economic assessment and technology roadmap

Human civilization’s food production system is unprepared for global catastrophic risks (GCRs). catastrophes capable of abruptly transforming global climate such as supervolcanic eruption, asteroid/comet impact or nuclear winter, which could completely collapse the agricultural system. Responding by producing resilient foods requiring little to no sunlight is more cost effective than increasing food stockpiles, given the long duration of these scenarios (6−10 years).This preliminary techno-economic assessment uncovers significant potential for synthetic fat from petroleum as a resilient food source in the case of an abrupt sunlight reduction catastrophe, the most severe food shock scenario. To this end, the following are roughly quantified based on literature data: global production potential, capital and operating expenditures, material and energy requirements, ramp-up rates and retail prices. Potential resource bottlenecks are reviewed.Synthetic fat production capacity would be slower to ramp up compared to low-tech food production alternatives, but provides the fat macronutrient, largely absent from these. Using 24/7 construction of facilities, 16–100% of global fat requirements could be fulfilled at the end of the first year, potentially taking up to 2 years to fully meet the requirements. Significant uncertainty remains on several topics including production potential, capital expenditure, food safety, transferability of labor and equipment construction. A technology roadmap is proposed to address these concerns and develop the potential of synthetic fat as a catastrophe-resilient food.

Excellent gas-sensitive properties towards acetone of In2O3 nanowires prepared by electrospinning

In2O3 nanowires (NWs) were successfully synthesized by electrospinning. The crystalline phase, microstructure, morphology, elemental composition, and BET surface area were analyzed XRD, SEM, TEM, XPS, and nitrogen adsorption. The characterization of the In2O3 NWs showed that In2O3 NWs were uniform thickness, structural integrity, and high purity. In subsequent gas-sensitive tests, the effects of PVP percentage, calcination temperature, calcination ramp-up rate, and calcination time on sensitive properties were analyzed. In particular, the In2O3 sensor showed a response of up to 37.9 (Ra/Rg) to 100 ppm acetone at an operating temperature of 200 °C and the response/recovery time is 1 s/7 s. The gas-sensitive mechanism of the In2O3 sensor was also analyzed in conjunction with the characterization results. Our study shows that the response of the In2O3 sensor is improved compared to the previously published sensors.

Thermally sprayed metal matrix composite coatings as heating systems

• Thermally sprayed metal matrix composite heating elements were developed and tested. • Effect of ceramic reinforcement on heating performance of the coatings was studied. • Electrical properties of the coatings noticeably affected their heating rate. • A heat transfer model was developed to predict the coating temperature distribution. Wind turbine blades and aircraft wings operating in extreme cold environments are prone to severe ice accretion. The accumulated ice may cause aerodynamic deficiency, lower durability, power losses, and significant safety issues. This study introduces a novel coating-based heating system that takes advantage of a certain group of materials, namely, metal matrix composite (MMC) coatings. With nickel chromium-aluminum-yttrium (NiCrAlY) as the metal matrix, coatings with different ceramic and cermet reinforcing phases were fabricated to produce electrical heating elements. The effects of coating microstructure and ceramic phases on the electrical properties and electrical resistance of the heating elements were examined. In order to assess the heating performance, a number of Joule heating experiments were conducted on the fabricated coatings. It was observed that MMC coatings with dielectric or semi-conductive reinforcing phases had considerably higher electrical resistance, heating ramp-up rate, and steady state temperature. A 2-dimensional transient heat conduction model with energy generation at the upper layer was developed to predict the temperature distribution in the multi-layered coating system. A similar heat conduction problem was simulated using ANSYS Mechanical software. The simulated results and that of the analytical model were in good agreement with the experimental data. The results of this study suggest that implementing ceramic reinforcements into MMC coatings will result in significant improvements in heating efficacy, and reduce consumption of energy in coatings-based de-icing systems.

Electric water heater flexibility potential and activation impact in system operator perspective – Norwegian scenario case study

Simultaneous activation of demand side flexibility on thermostatically controlled loads will cause adverse impacts later in the form of rebounds. Distribution system operators must know the characterisation of the impact, as they are responsible for voltage quality of power delivery and suffer the loss of lifespan of network components due to overloading. In this paper, characterising parameters for flexibility activation on electric water heaters (EWHs) are proposed and flexibility potentials are computed considering smart activation methods for the Norwegian scenario. The proposed parameters are rebound percentage, delay, ramp rates, second peak distance, activation error, flexible power, and temperature deviation. Four scenarios with different levels of flexible power and activation time are developed in the Norwegian context for quantification of the flexibility potentials and the parameters. The highest average flexible power potential is 53.9% at 8:00 a.m. for a duration of 61 min. EWHs flexibility activation can serve as Frequency Containment Reserves (FCR) at peak demand hours with high ramp-up and ramp-down rates of 48.5% and 23.8% per minute and as Frequency Restoration Reserves (FRR) during non-peak hours.

Information gap decision theory (IGDT)-based robust scheduling of combined cooling, heat and power energy hubs

Energy hubs (EHs) are units wherein multiple energy carriers can be converted, stored and conditioned to simultaneously supply different energy demands. In this paper, a new model is proposed for unit commitment in renewable EHs with electric, thermal and cooling demands, different storage systems, combined heat and power (CHP) unit, boiler, electric chiller, absorption chiller, PV module, wind turbine and battery charging station (BCS). Using information gap decision theory (IGDT), day-ahead EH scheduling is done from risk-neutral, risk-averse and risk-seeking perspectives, considering the uncertainties of electric demands, BCS demands, heat demands, cooling demands, PV and wind power and electricity prices. Comprehensive models are used for storage systems considering their degradation, charging loss, discharging loss and storage loss; the ramp-up and ramp-down rate limits, start-up and shut-down costs of CHP, boiler and cooling components are considered. The effect of risk as well as effect of critical cost deviation factor and target cost deviation factor on EH operation cost and schedule of EH components is investigated. The findings indicate that the sensitivity of EH operation cost may be very different with respect to different sets of uncertain input data. The findings also show the significant effect of risk-awareness on schedule of EH components and its operation cost.