A Method for Evaluating Market Value of Turbine Gaspath Component Alternatives

2002 ◽  
Author(s):  
Fred T. Willett
Keyword(s):  
Power Plant ◽  
Spot Market ◽  
Simple Cycle ◽  
Price Reduction ◽  
First Year ◽  
Short Term ◽  
Plant Operator ◽  
Cooling Flow ◽  
Power Plant Operator

An economic model was developed to evaluate gas turbine component alternatives for base load combined cycle operation, cyclic duty simple cycle operation, and peaking duty simple cycle operation. Power plant operator value of alternative replacement first stage buckets for a GE Frame 7EA gas turbine is evaluated. The popularity and large installed base of the 7EA has prompted a number of replacement part offerings, in addition to the replacement parts offered by the OEM. A baseline case is established to represent the current bucket repair and replacement situation. Each of the modes of power plant operation is evaluated from both a long-term financial focus and a short-term financial focus. Long-term focus is characterized by a nine-year evaluation period, while short-term focus is based on first year benefit only. Four factors are considered: part price repair price, output increase, and simple cycle efficiency increase. Natural gas and liquid fuels are considered. Two natural gas prices are used; one liquid fuel price is considered. Peak, off-peak, and spot market electricity prices are considered. Two baseline repair price scenarios are evaluated: 50% of new part price and 10% of new part price. The key conclusions can be summarized as: • A reduced-life part with more frequent repair intervals is undesirable, even if the part price is reduced by over 60% and the cooling flow is reduced by 1% W2. • A short-life, “throw-away” part with no required repairs can achieve parity with the baseline if the price is reduced by 25% or more. The operator with a short-term focus will not differentiate between a “throw-away” part and a full-life part. • In general, increased part life has less value to the power plant operator than price reduction or cooling flow reduction. • Repair price (assumed to be 50% of part price) is a relatively small factor for operators with a long-term focus, and no factor at all for operators with a short-term focus. A lower baseline repair price (10% of part price) will decrease the attractiveness of a “throw-away” part, moving the parity point to a 40% price reduction. • A 0.7% W2 reduction in cooling flow has roughly the same first year benefit, at baseline fuel prices, as a 10–15% bucket price reduction, except to the peak duty operator. The peak duty operator finds no benefit to reduced cooling flow unless electricity can be sold at spot market prices.

An Improved Method for Evaluating Market Value of Turbine Gaspath Component Alternatives

2003 ◽  
Author(s):  
Fred T. Willett ◽  
Michael R. Pothier
Keyword(s):  
Power Plant ◽  
Gas Turbines ◽  
Net Present Value ◽  
Risk Level ◽  
Improved Method ◽  
Short Term ◽  
Plant Operator ◽  
Efficiency Increase ◽  
Industrial Gas Turbines

The large installed base of large frame industrial gas turbines has prompted a number of replacement part offerings, in addition to the replacement parts offered by the OEM. Willett [1] proposed an economic model developed to evaluate gas turbine component alternatives for base load and cyclic duty operation. The improved method expands the capability of the earlier model by including risk level as a variable. Power plant operator value of alternative replacement turbine components for a popular large frame industrial gas turbines is evaluated. A baseline case is established to represent the current component repair and replacement situation, assuming no risk. Each of the modes of power plant operation is evaluated from a long-term financial focus. A short-term financial focus is evaluated for contrast and discussed briefly. Long-term focus is characterized by a nine-year evaluation period, while short-term focus is based on first year benefit only. Four factors are varied: part price, output increase, simple cycle efficiency increase, and additional risk. Natural gas fuel is considered at two different gas prices. Peak, off-peak, and spot market electricity prices are considered. Results are calculated and compared using net present value (NPV) criteria. A case study is presented to demonstrate the method’s applicability to a range of different risk scenarios, from ill-fitting replacement parts to catastrophic turbine failure.

Operator Monitoring during Normal Operations: Vigilance or Problem-Solving?

1997 ◽  
Vol 41 (1) ◽  
pp. 158-162 ◽  
Author(s):  
Emilie M. Roth ◽  
Randall J. Mumaw ◽  
Kim J. Vicente ◽  
Catherine M. Burns
Keyword(s):  
Problem Solving ◽  
Power Plant ◽  
Vigilance Task ◽  
Dynamic Environments ◽  
Control Room ◽  
Cognitive Demands ◽  
Emergency Operations ◽  
Plant Operator ◽  
Attention Process ◽  
Power Plant Operator

Monitoring during emergencies in dynamic environments is widely recognized to be an active, selective attention, process. In contrast monitoring during normal operations is often thought to more closely resemble a vigilance task. This paper describes a field study of power plant operator monitor during normal operations. We observed and interviewed 27 operators at two different plants for a total of over 200 hours. Despite differences in control room technology, we found that in both cases operators devised active strategies to remove or reduce meaningless changes from the interface, create information different from that intended by the designers, and make important information more salient. These findings were integrated into a model of operator monitoring, that emphasizes operators' use of strategies for knowledge-driven monitoring and proactive adaptation of the control room interface. The model is equally applicable for normal and emergency operations and underscores the commonality in cognitive demands in both environments.

scholarly journals Short-Term Bidding Strategy for a Price-Maker Virtual Power Plant Based on Interval Optimization

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3662
Author(s):  
Jiakai Hu ◽  
Chuanwen Jiang ◽  
Yangyang Liu
Keyword(s):  
Power Plant ◽  
Mathematical Problem ◽  
Interval Optimization ◽  
Equilibrium Constraints ◽  
Virtual Power ◽  
Interval Numbers ◽  
Virtual Power Plant ◽  
Plant Operator ◽  
Bidding Price ◽  
Power Plant Operator

A virtual power plant is proposed to aggregate various distributed renewable resources with controllable resources to overcome the uncertainty and volatility of the renewables so as to improve market involvement. As the virtual power plant capacity becomes remarkable, it behaves as a strategic price maker rather than price taker in the market for higher profit. In this work, a two-stage bi-level bidding and scheduling model is proposed to study the virtual power plant strategic behaviors as a price maker. A mathematical problem with an equilibrium constraints-based method is applied to solve the problem by transforming the two level problem into a single level multi-integer linear problem. Considering the deficiency of computational burden and implausible assumptions of conventional stochastic optimization, we introduce interval numbers to represent the predicted output of uncertainty resources in a real-time stage. The pessimism degree-based method is utilized to order the preferences of profit intervals and tradeoff between expected profit and uncertainty. An imbalance cost mitigation mechanism is proposed in this pessimism degree-based interval optimization manner. Results show that the bidding price directly affects the cleared day ahead of the locational marginal price for higher profit. Interior conventional generators, energy storage and interruptible loads are comprehensively optimized to cover potential power shortage or profit from market. Moreover, controllable resources can decrease or even wipe out the uncertainty through the imbalance cost mitigation mechanism when the negative deviation charge is high. Finally, a sensitivity analysis reveals the effect of interval parameter setting upon optimization results. Moreover, a virtual power plant operator with a higher pessimism degree pursues higher profit with higher uncertainty.

Effects of Wetness in Steam Turbines

2005 ◽  
Vol 219 (12) ◽  
pp. 1301-1314 ◽  
Author(s):  
J A Hesketh ◽  
P J Walker
Keyword(s):  
Power Plant ◽  
Mechanical Engineering ◽  
Mechanical Damage ◽  
Axial Flow ◽  
Engineering Science ◽  
Steam Turbines ◽  
Plant Operator ◽  
Power Plant Operator ◽  
General Practices ◽  
The Subject

Courses in mechanical engineering usually introduce the theory of axial-flow turbo-machines in terms of simple velocity triangles representing the bulk flow of ideal compressible fluid through the blade passages. A distinctive practical difference, peculiar to steam turbines (ST), is the presence of liquid-water in the flow field. The steam wetness in such turbines is widely known to be doubly-damaging, leading to both loss of efficiency and to mechanical damage (erosion, etc.) of the machine components. Over recent decades, a whole new field of mechanical engineering science has evolved on the subject of wetness in steam turbines, and general practices have been established within the industry. This article reviews the general effects that are of major importance to the turbine designer/engineer, power plant operator, and especially to researchers in this field.

In Vivo Selection Unmasks a Dormant Pool of Repopulating Hematopoietic Clones

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 242-242
Author(s):  
Jennifer E Adair ◽  
Lauren E Schefter ◽  
Daniel R Humphrys ◽  
Kevin G Haworth ◽  
Jonah D Hocum ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Selective Advantage ◽  
First Year ◽  
Short Term ◽  
Hematopoietic Stem ◽  
In Vivo Selection ◽  
Chemotherapy Administration ◽  
Cd34 Cells

Abstract Long-term clonal tracking studies utilizing hematopoietic stem and progenitor cells (HSPCs) in nonhuman primates receiving myeloablative transplantation demonstrate a successive pattern of repopulation: short-term repopulating cells are succeeded by long-term clones. However, the duration of short-term repopulation and the numbers of clones contributing to either short or long-term repopulation are unclear. Here, we tracked >11,000 unique clones in 8 pigtail macaques for up to 9 years following myeloablative transplantation with autologous, lentivirus gene-modified CD34+ HSPCs. Seven of these animals received cells expressing the P140K mutant methylguanine methyltransferase transgene, which is resistant to the combination of O6-benzylguanine (O6BG) and bis-chloroethylnitrosourea (BCNU) chemotherapy, thus conferring a selective advantage to gene-modified cells in vivo. After transplantation and before in vivo selection with O6BG/BCNU, we observed a successive pattern of hematopoietic reconstitution, with short-term clones declining within 100 days after transplantation. Within the first year after transplant, the percent of persistent clones varied from animal-to-animal, ranging from 8% to 54% of clones detected at a >1% frequency, and remained stable in the absence of selective pressure. Importantly, when animals engrafted with P140K-expressing cells were administered O6BG/BCNU we observed novel clonal patterns, which directly correlated with transplanted cell dose and time of chemotherapy administration after transplant. In all animals, chemotherapy induced emergence of previously undetected clones. In animals receiving ≤12x106 CD34+ cells/kg at the time of transplant (n = 4), chemotherapy also induced a re-emergence of previously declined short-term repopulating clones or a stabilization (i.e. decreased fluctuation) of repopulating clones identified between 100 days and 1 year after transplant. However, in animals receiving robust cell doses, ≥35x106 CD34+ cells/kg (n = 2), chemotherapy more than 1 year after transplant induced a completely novel clonal repertoire. In one animal receiving 22x106 CD34+ cells/kg at transplant, chemotherapy administration beginning <1 year (253 days) after transplant induced clonal stability, which was maintained through two additional chemotherapy treatments. These data suggest that some short-term repopulating clones may have long-term repopulation ability, but revert to a dormant phase within the first year after transplant. Additionally, these data indicate that transplant of excess repopulating cells results in early dormancy of a large proportion of repopulating clones. Together, these findings suggest that previous estimates of HSPC frequency based on clone tracking are an underestimate of true graft repopulation potential. Disclosures No relevant conflicts of interest to declare.

scholarly journals Implanted satellite transmitters affect sea duck movement patterns at short and long timescales

The Condor ◽  
2020 ◽  
Vol 122 (3) ◽  
Author(s):  
Juliet S Lamb ◽  
Peter W C Paton ◽  
Jason E Osenkowski ◽  
Shannon S Badzinski ◽  
Alicia M Berlin ◽  
...  
Keyword(s):  
Breeding Site ◽  
Behavioral Changes ◽  
First Year ◽  
Behavioral Patterns ◽  
Telemetry Data ◽  
Short Term ◽  
Satellite Transmitters ◽  
Males And Females ◽  
Long Timescales

Abstract Studies of the effects of transmitters on wildlife often focus on survival. However, sublethal behavioral changes resulting from radio-marking have the potential to affect inferences from telemetry data and may vary based on individual and environmental characteristics. We used a long-term, multi-species tracking study of sea ducks to assess behavioral patterns at multiple temporal scales following implantation of intracoelomic satellite transmitters. We applied state-space models to assess short-term behavioral patterns in 476 individuals with implanted satellite transmitters, as well as comparing breeding site attendance and migratory phenology across multiple years after capture. In the short term, our results suggest an increase in dispersive behavior immediately following capture and transmitter implantation; however, behavior returned to seasonally average patterns within ~5 days after release. Over multiple years, we found that breeding site attendance by both males and females was depressed during the first breeding season after radio-marking relative to subsequent years, with larger relative decreases in breeding site attendance among males than females. We also found that spring and breeding migrations occurred later in the first year after radio-marking than in subsequent years. Across all behavioral effects, the severity of behavioral change often varied by species, sex, age, and capture season. We conclude that, although individuals appear to adjust relatively quickly (i.e. within 1 week) to implanted satellite transmitters, changes in breeding phenology may occur over the longer term and should be considered when analyzing and reporting telemetry data.

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