PV Energy Forecasting via Empirical Normalized Irradiation
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Solution Overview
Problem
Current methods for estimating photovoltaic energy production in fleets face challenges due to inaccuracies in irradiance and normalized irradiation data, particularly when historical solar irradiance data is lacking, and there is a need for an approach that can facilitate accurate photovoltaic power simulation.
Innovation Solution
A system and method for estimating photovoltaic energy through empirical derivation using a digital computer, which involves obtaining solar irradiance data, calculating clear sky irradiance, and using an optimization approach to derive a weighting factor array. This array is then used to estimate normalized irradiation, which is further used to forecast photovoltaic fleet energy production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional irradiance and normalized irradiation data are used for photovoltaic production forecasting, then the forecasting process can be performed, but the accuracy of production data is compromised due to data inaccuracies and confusion between irradiance and normalized irradiation
Solution Approach 1:
The patent introduces an intermediary computational process that transforms raw irradiance data into normalized irradiation values through a defined mathematical relationship. This intermediary step acts as a mediator between the measured irradiance and the required normalized irradiation, ensuring accurate conversion while maintaining the distinction between the two parameters. The system uses this intermediary calculation to produce reliable production forecasts without directly relying on potentially inaccurate normalized irradiation measurements.
2Productivity
If photovoltaic fleets are integrated into power grids to meet growing renewable energy demand, then energy production capacity increases, but the complexity of managing and forecasting production across distributed locations increases
Solution Approach 1:
The patent creates a universal forecasting system that can handle multiple photovoltaic fleet configurations and locations through a single standardized methodology. The system uses consistent mathematical relationships and computational approaches that work across different geographic locations, fleet sizes, and system configurations, eliminating the need for location-specific complex models and simplifying fleet management while maintaining high productivity.
3Productivity
If irradiance data is used to estimate normalized irradiation without proper distinction, then calculations can be performed quickly, but simulation inaccuracies occur due to confusion between rate and quantity measures
Solution Approach 1:
The patent applies parameter changes by transforming the irradiance parameter into normalized irradiation through a specific mathematical relationship that accounts for the temporal dimension. Rather than simply using irradiance values directly, the system changes the parameter state by applying integration or averaging over time periods, thereby converting the instantaneous rate measure into the required quantity measure while maintaining computational efficiency and simulation accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed method enables accurate forecasting of photovoltaic fleet energy production by addressing the challenges of irradiance and normalized irradiation data inaccuracies, and it supports any photovoltaic fleet configuration and time resolution, making it suitable for electric power grid planning and operation.
Implementation Method 1
A weighting factor array is empirically derived using an optimization approach and a set of measured irradiance and the irradiance observations associated with the at least some measured irradiance
Implementation Method 2
A photovoltaic energy production for the photovoltaic plant is forecasted as a function of the time series of the clearness indexes and photovoltaic plant's power rating
Data Source
AI summary
The accuracy of photovoltaic simulation modeling is predicated upon the selection of a type of solar resource data appropriate to the form of simulation desired. Photovoltaic power simulation requires irradiance data. Photovoltaic energy simulation requires normalized irradiation data. Normalized irradiation is not always available, such as in photovoltaic plant installations where only point measurements of irradiance are sporadically collected or even entirely absent. Normalized irradiation can be estimated through several methodologies, including assuming that normalized irradiation simply equals irradiance, directly estimating normalized irradiation, applying linear interpolation to irradiance, applying linear interpolation to clearness index values, and empirically deriving irradiance weights. The normalized irradiation can then be used to forecast photovoltaic fleet energy production.