Energy Yield and Clipping Loss Corrections for Hourly Inputs in Climates with Solar Variability

Kharait, Rounak; Raju, Simran; Parikh, Abhishek; Mikofski, Mark A.; Newmiller, Jeff

doi:10.1109/pvsc45281.2020.9300911

Cited by 8 publications

(2 citation statements)

References 4 publications

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“…It has been found that using simulations in hourly resolution introduces systematic modeling bias errors that need the be corrected. [28][29][30] The hemicube model enables simulations of subhourly temporal resolution without additional computing requirements to accurately capture shading effects.…”

Section: Storing the Results In A Lookup Tablementioning

confidence: 99%

Shading in Utility‐Scale Photovoltaic Plants: A Hemicube Approach for Efficient Shading Calculations

Neubert¹,

Hamer²,

Lopez‐Lorente

2023

Solar RRL

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Accurate estimations of energy production in the planning and design stage of photovoltaic (PV) plants require advanced and efficient models to simulate shading effects. This is particularly important for plants located in complex terrain or plants that are affected by nearby shading obstacles. Herein, a hemicube approach is presented for calculating shading effects and assessing the model accuracy and performance for utility‐scale PV plants. The proposed model is thoroughly illustrated for common direct beam and diffuse irradiance shading effects occurring in solar plants. The article illustrates how the accuracy and computing needs of the model can be affected by the tuning of key parameters using as case studies several PV plants from 1 to 100 MW and different ground coverage ratios. The model is validated in a 16 MW PV plant located in a complex terrain. Finally, the results demonstrate how the proposed hemicube model can be set to leverage accurate and efficient computing performance. The proposed hemicube‐based shading model has been implemented in SolarFarmer, a commercial PV design software, to facilitate the PV industry, produce accurate energy yield assessments, and support the ongoing clean energy transition.

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Section: Storing the Results In A Lookup Tablementioning

confidence: 99%

Shading in Utility‐Scale Photovoltaic Plants: A Hemicube Approach for Efficient Shading Calculations

Neubert¹,

Hamer²,

Lopez‐Lorente

2023

Solar RRL

View full text Add to dashboard Cite

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“…This leads to an overprediction bias in simulations that rely on coarse temporal resolution (e.g., hourly) data. 7,8 Studies have also used schemes to classify high-and low-variability time periods using variability metrics based on both the clear-sky index 9 and direct solar irradiance. 10 The spatiotemporal nature of variability has been characterized by a number of studies.…”

Section: A Characterizing Variabilitymentioning

confidence: 99%

Cloud advection model of solar irradiance smoothing by spatial aggregation

Ranalli

Peerlings

2021

Journal of Renewable and Sustainable Energy

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Solar generation facilities are inherently spatially distributed and therefore aggregate solar irradiance in both space and time, smoothing its variability. To represent the spatiotemporal aggregation process, most existing studies focus on the reduced correlation in solar irradiance throughout a plant's spatial distribution. In this paper, we derived a cloud advection model that is instead based upon lagging correlations between upwind/downwind portions of a distributed plant, induced by advection of a fixed cloud pattern over the plant. We use the model to calculate a plant transfer function that can be used to predict the smoothing of the time series. The model was validated using the distributed HOPE-Melpitz measurement dataset, which consisted of 50 solar irradiance sensors at 1 s temporal resolution over a 3 Â 2 km 2 bounding area. The initial validation showed that the advection-based model outperforms other models at predicting the smoothed irradiance time series during manually identified, advection dominated conditions. We also conducted validation on the model against additional advection dominated periods in the dataset that were identified algorithmically. The cloud advection model's performance compared well to models in literature, but degraded slightly as larger cross-wind plant distributions were investigated. The results in this paper highlight the need to incorporate advection effects on spatial aggregation during advection dominated conditions. Future development of spatiotemporal aggregation models is needed to unify advective models with existing correlation reduction models and to identify regimes where each dominate.

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The effect of short-term inverter saturation on modeled hourly PV output using minute DC power measurements

Allen

Hobbs

2022

Journal of Renewable and Sustainable Energy

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PV system modeling is primarily done on hourly timescales, and so cannot capture subhourly effects, including inverter saturation. Inverter saturation occurs when the potential dc power, Pdc, produced by the collectors is greater than the inverter capacity, and some of the PV power is lost or "clipped". The inverter clips power rapidly, and calculations based on hour-averaged Pdc will overestimate ac power output for hours in which clipping occurs intermittently. Clipping is greater in systems with high ratios of collector to inverter capacity, "dc:ac ratio". We studied this modeling error using minute-scale Pdc measurements from a test site in Birmingham AL that had 4 different mounting configurations equipped with oversized inverters; i.e., 0.8 dc:ac ratio. PV output was calculated using minute- and hour-averaged Pdc, and modeled inverters with dc:ac ratios up to 2.0. The modeling errors due to short term inverter saturation were approximately 2% of the annual output for 1.4 dc:ac ratios. We present the effect of mounting type, dc:ac ratio, season, and hour-of-day on these errors for the study site.

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Energy Yield and Clipping Loss Corrections for Hourly Inputs in Climates with Solar Variability

Cited by 8 publications

References 4 publications

Shading in Utility‐Scale Photovoltaic Plants: A Hemicube Approach for Efficient Shading Calculations

Shading in Utility‐Scale Photovoltaic Plants: A Hemicube Approach for Efficient Shading Calculations

Cloud advection model of solar irradiance smoothing by spatial aggregation

The effect of short-term inverter saturation on modeled hourly PV output using minute DC power measurements

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