skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Benchmarking performance of photovoltaic power plants in multiple periods
There is a general consensus about the performance of photovoltaic plants particularly on their efficiency benefits. However, it is not clear to what extents such efficiencies correlate with the efficient frontier of performance when such plants are evaluated under varying geospatial environmental factors and over intertemporal periods. This study carries out a performance benchmarking exercise on photovoltaic power stations. It employs a non-parametric modelling technique in the form of Data Envelopment Analysis to evaluate the performance over time of three photovoltaic power plants within an electric utility. It presents an optimization modelling approach for performance benchmarking over time under situations where there are a limited number of decision-making units. Specifically, the study introduces a multi-period modeling approach which employs real data and captures actual variabilities in environmental factors that influence the output of photovoltaic power plants over time. In comparing the deterministic approach often employed in the extant literature with the multi-period model, the results reveal that the deterministic model overestimates the efficiency values and underestimates the output targets relative to a unit operating on the efficient frontier. The study further employs non-parametric statistical techniques and post-hoc tests to validate the findings.  more » « less
Award ID(s):
1847077
PAR ID:
10492340
Author(s) / Creator(s):
;
Publisher / Repository:
Springer
Date Published:
Journal Name:
Environment Systems and Decisions
Volume:
43
Issue:
3
ISSN:
2194-5403
Page Range / eLocation ID:
489 to 503
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    This study presents a time-efficient modelling approach for dynamic behavior and efficiency analysis of a Switched Reluctance Machines (SRM). It employs a hybrid model combining Simulink, finite element analysis (FEA), and hardware measurements to create an accurate behavioral model of the machine. In order to enhance accuracy of the estimated performance, Steinmetz equation is employed to characterize core loss in the machine across different operating points. This approach serves as a template for developing a time-efficient model to analyze performance of any SRM with a high degree of accuracy. Simulation and experimental results are used to show effectiveness of the proposed approach. 
    more » « less
  2. Waleed Khalil (Ed.)
    The increasing performance demanded by emerging wireless communication standards motivates the development of various techniques devoted to improving the efficiency of power amplifiers (PA) because this is one of the most power-demanding blocks in RF transceivers. Power-amplifier efficiency is proportional to the ratio of the average voltage delivered by the PA to the voltage level of the PA's power supply. Efficiency is affected by the peak-to-average ratio of the transmitted signal. The envelope tracking modulator maximizes this ratio, correlating the PA's power supply with the envelope of its output signal. Efficient modulators must satisfy certain critical conditions: i) it must be very agile to track the amplitude variations of PA's output voltage; ii) it must reduce the timing mismatch between the PA modulator's supply and PA output waveform envelope to optimize power efficiency and avoid PA saturation, and iii) the envelope tracking modulator must be highly power efficient. This paper reviews several relevant envelope tracking techniques. Hybrid modulators consisting of switching regulators and linear amplifiers have become mainstream envelope tracking systems for wideband applications, in which linear amplifiers complement the functionality of highly efficient but narrow bandwidth switching modulators. Replacements for linear amplifiers include a combination of power-efficient ADC and DACs that provide very agile feedback, increasing the system's slew rate, which allows the modulator to track faster envelope signals. Multi-level switching is another relevant approach utilizing multiple switching voltages to reduce current ripples and enable the use of wider bandwidth switching regulators with high power efficiency. The use of multiple inductors is another interesting approach. Multi-phase switching techniques utilize multiple switching stages in a time-interleaved manner to extend the switching modulator's bandwidth. A slow buck converter can be combined with a fast buck converter and optimized for different switching frequencies; this architecture covers the signal envelope's low- and high-frequency components. The approaches mentioned use switching modulators with analog feedback controllers (Pulse-width modulation [PWM] or hysteretic). However, an alternative approach is prediction-based digital feedforward control. This tutorial discusses all of these approaches. 
    more » « less
  3. L. Cromarty, R. Shirwaiker (Ed.)
    This study investigates the renewable energy adoption across regions covered by Independent System Operators (ISOs) in the U.S. The study employed a deterministic model in the form of Data Envelopment Analysis (DEA) to determine the performance of ten ISO regions over a five-year period from 2013 to 2017. Inputs into the model include the Renewable Portfolio Standard (RPS) targets, fossil fuel capacity additions and the costs of capacity additions. Outputs from the model include renewable energy capacity additions and CO2 emissions per MWh of generated electricity. The results show the regions covered by CAISO, ERCOT, NE-ISO, SPP and the NON-ISO to be on the efficient frontier. For the regions not on the efficient frontier, the results identify their limitations and provide projections both for reductions in excess inputs and improvements in outputs to be on the efficient frontier. For example, we see that the regions covered by NY-ISO and PJM would require, on average, renewable energy capacity expansions of 593.65MW and 230.24MW, respectively, to be on the efficient frontier. These regions would require their average fossil capacity expansions to be limited to 234.83MW and 365.4MW respectively. These findings offer some guidance on approaches to improving the performance of these markets. 
    more » « less
  4. The use of multi-output look-up tables (LUTs) is a widely adopted approach in contemporary commercial field-programmable gate arrays (FPGAs). Larger LUT configurations (e.g., six-input LUTs) can be partitioned into smaller LUTs (e.g., two five-input LUTs, maintaining a total input count of less than six). This capability of generating a second output from a larger LUT is not only crucial for reducing logic cell count and enhancing the utilization efficiency of logic resources—thus conserving area—but also plays a key role in optimizing system-level delays and energy consumption. In this paper, we propose an efficient multi-output LUT mapping technique, incorporating several highly efficient technology mapping algorithms, which focus on optimizing the mapping from an interconnection perspective as alternatives to directly merging smaller LUTs. These algorithms include a side-fanout insertion algorithm, and a runtime multi-output cut generation algorithm. The proposed methods improve mapping efficiency and enhance performance. The benchmarking results demonstrate that the dual-output mapping algorithms achieve LUT area reductions of up to 35% and 6%, compared to the state-of-the-art ABC six-input, single-output LUT mapping technique and previous work focusing on dual-output LUT mapping techniques that optimize cut generation parameters. Moreover, FPGA system-level simulations also show that area, delay, and energy can all be optimized based on this multi-output mapping technique. 
    more » « less
  5. To improve the power delivery in System-on-Chips (SoCs), this paper proposes a single-input-multi-output (SIMO) hybrid converter to obtain fast response time, low cross-regulation, and 87% peak efficiency by using a multi-output hybrid power stage and dual-switching-frequency technique. The multiple-output hybrid power stage improves the conversion efficiency without sacrificing the output voltage range, and the dual-switching-frequency technique enhances the response time and cross-regulation performance. The proposed SIMO hybrid converter achieves 87.5% peak efficiency with an output voltage range from 0.4V to 1.6V for all outputs and a total maximum load current of 450mAAdditionally, it achieves less than 0.01mA/mV cross-regulation and less than 20mV overshoot at full-load step transient response. 
    more » « less