Solar Prediction

Developers, utilities and independent system operators depend on accurate time-series solar irradiance data for project siting, planning and operations. Groundbreaking solar prediction research quantifies the accuracy of PV output modeling, solar irradiance data and irradiance forecasting, as well as describing methods for modeling high-speed PV output variability.

Accuracy of Satellite-Derived Solar Irradiance Data, Solar Irradiance Forecasts & PV Performance Models

This research provides government researchers, utilities, independent system operators and developers information on PV power output models and methods of calculating and quantifying the accuracy of satellite-derived solar irradiance data for specific applications.
Enhancing Temporal Variability of 5-minute Satellite-Derived Solar Irradiance Data
 |  June 2022

Satellite-derived solar irradiance data are known to underestimate temporal variability compared to point measurements...

A Review of Solar Forecasting, Its Dependence on Atmospheric Sciences and Implications for Grid Integration: Towards Carbon Neutrality
 |  March 2022

The ability to forecast solar irradiance plays an indispensable role in solar power forecasting, which constitutes an...

Investigations of Site-Specific, Long Term Average Albedo Determination for Accurate Bifacial System Energy Modeling
 |  June 2019

As interest in bifacial PV modules grows, there is a need to quantify the impact of additional energy generation for...

Improved PV System Modeling with ML-Based Power Model: Case Study of a Commercial Building
+  |  May 2019

Solar PV system specifications are critical to accurately modeling PV system production (along with high-quality...

Improved model of solar resource variability based on regional aggregation and climate zones
 |  June 2018

This paper provides the results of using an alternative method to calculate annual insolation probability of...

Detecting Calibration Drift at Ground Truth Stations: A Demonstration of Satellite Irradiance Models’ Accuracy
 |  July 2017
Day-Ahead Irradiance Forecast Variability Characterization Using Satellite Data
 |  June 2016

This article calculates day-head forecast variability as function of historical clearness index based on intraday...

Solar Energy Forecast Validation for Extended Areas & Economic Impact of Forecast Accuracy
 |  June 2016

This article evaluates the accuracy of solar forecast models, including SolarAnywhere®, as a function of geographic...

Satellite-to-Irradiance Modeling – A New Version of the SUNY Model
 |  May 2015

This article presents and validates the latest version of the SUNY model for using satellite imagery to calculate...

CEC PIER Project: Demonstration and Validation of PV Output Variability Modeling Approach
 |  July 2013

The California Energy Commission’s Public Interest Energy Research (CEC PIER) program awarded Clean Power Research a...

Operational Improvements in the Performance of the SUNY Satellite-to-Solar Irradiance Model Using Satellite Infrared Channels
 |  June 2013

This paper summarizes operational improvements to the existing SUNY satellite-to-solar irradiance model used to...

Solar Monitoring, Forecasting and Variability Assessment at SMUD
 |  April 2012

This paper summarizes the deployment of a 71 station solar monitoring network in Sacramento, Calif., and its use in...

Predicting Short-term Variability of High Penetration PV
 |  March 2012

This article evaluates the ability of three operational satellite models (SolarAnywhere® Standard, Enhanced, and High...

Reporting of Irradiance Model Relative Errors
 |  March 2012

Metrics used in assessing irradiance model accuracy such as Root Mean Square Error (RMSE) and Mean Absolute Error...

Evaluating Irradiance Accuracy Using California ISO Data: Lessons Learned
+  |  February 2012

This presentation provides the results of a study evaluating the short, medium and long-term accuracy of irradiance...

Validation of Short & Medium Term Operational Solar Radiation Forecasts in the U.S.
 |  August 2010

This paper presents a validation of the short- and medium-term global irradiance forecasts that are produced as part...

Validation of PV Performance Models Using Satellite-based Irradiance Measurements: A Case Study
 |  May 2010

This paper presents a study of how PV performance model results are affected when satellite-based weather data is used...

Field Validation of the Clean Power Estimator’s Obstruction Analysis Algorithm
 |  February 2004

This paper validates the Clean Power Estimator obstruction analysis algorithm based on results produced by the Solar...

Validation of a Simplified PV Simulation Engine
 |  June 2003

This paper describes and validates a simple PV simulation model capable of predicting average PV output as a function...

Combining Solar Satellite & Ground Data to Reduce Solar Project Uncertainty

These papers highlight the benefit of combining high-quality solar ground data with satellite derived solar irradiance data to reduce solar project uncertainty.
Importance of Input Data and Uncertainty Associated with Tuning Satellite to Ground Solar Irradiation
 |  June 2016

Although the uncertainty of satellite data such as SolarAnywhere® Data has been shown to be low, it can be challenging...

On the Ability of Ground Based Global Horizontal Irradiance Measurements to Reduce Error in Satellite Derived Plane of Array Irradiance data for Fixed Tilt Photovoltaic Power Plants
 |  June 2016

This paper quantifies the residual errors in plane of array irradiance (POAI) at locations where ground-measured GHI...

Combining Satellite and Ground Data: What Works & What Doesn’t
+  |  February 2015

In this presentation, you'll learn about which type of solar irradiance data—typical year, ground or satellite—is...

Reducing Solar Project Uncertainty with an Optimized Resource Assessment Tuning Methodology
 |  June 2014

This paper describes procedures suitable for the optimal combination of ground-based and satellite-based irradiance...

Determining the Value of Photovoltaic (PV) Solar Power Using Solar Prediction & Data Modeling

Solar developers and utility planners are often faced with the task of determining the solar energy output & economic value of one or more PV systems. This research offers insights into the solar energy value assessment process.
A Condensed Analysis of Firm Wind & Solar Power Generation in Nova Scotia
 |  January 2026

This report summarizes the key findings from a comprehensive study performed by Clean Power Research for Natural...

Localized, Cost-Effective, 100% Renewable Firm Power Generation
 |  November 2025

Recent International Energy Agency (IEA) studies demonstrate that it is possible to cost-effectively achieve firm...

On the Complementary Variability of the Solar and Wind Resources
 |  August 2025

This article evaluates and contrasts the variability of large-scale, distributed wind and PV generation across the...

Nonparametric Temporal Downscaling of GHI Clear-sky Indices Using Gaussian Copula
 |  June 2022

Small-scale variabilities of solar irradiance are important for many applications. Downscaling approaches need to be...

Solar Energy Forecast Validation for Extended Areas & Economic Impact of Forecast Accuracy
 |  June 2016

This article evaluates the accuracy of solar forecast models, including SolarAnywhere®, as a function of geographic...

Off-Shore Wind and Grid-Connected PV: High Penetration Peak Shaving for New York City
 |  March 2012

This article presents an experimental evaluation of the combined effective capacity of off-shore wind and...

Valuing a Portfolio of PV Investments
+  |  October 2010

This presentation describes the importance of PV output variability as a factor in calculating the value of a fleet of...

Weather Adjusted Performance Guarantees
 |  May 2010

This paper describes how to generate more accurate Weather-Adjusted Performance Guarantees for PV systems using a...

Shining on the Big Apple: Satisfying New York City’s Peak Electrical Needs with PV
+  |  November 2008

This presentation describes how measured data was used to evaluate the potential of PV to satisfy the electrical needs...

Forecasting Solar Irradiance With High-Penetration Distributed Photovoltaics (PV)

The intermittent nature of solar energy using PV requires utilities and independent system operators to adapt their planning, scheduling and operating strategies to maintain grid reliability and get the most value out of installed PV resources. These papers describe projects that use advanced methodologies to forecast high-penetration PV fleet solar energy output, and integrate solar energy forecasts into grid system operations.
Firm Wind and Solar Power Generation in Nova Scotia with Fully Electrified Transportation and Building Sectors
 |  March 2025

This report examines the feasibility and cost-effectiveness of firm renewable power generation in Nova Scotia under a...

Extending Fleet Forecasting Capability into the Probabilistic Realm
+  |  July 2019

This presentation demonstrates how a new approach to PV fleet forecasting can address the problem of artificially high...

EPIC Solar Forecasting Task 3 Final Report: Grid-Connected and Embedded PV Fleet Forecasting Accuracy
 |  April 2018

This report, prepared with an Electric Program Investment Charge (EPIC) fund, describes new methods for improving...

EPIC Solar Forecasting Task 2 Final Report: Data Forecasting Accuracy
 |  April 2018

This report, prepared with an Electric Program Investment Charge (EPIC) fund, describes the results of research to...

Advancing the Science of Behind-the-Meter PV Forecasting
+  |  February 2018

This presentation discusses how probabilistic forecasting enables electric utilities and grid operators to reduce...

Integration of Behind-the-Meter PV Fleet Forecasts into Utility Grid System Operations
 |  February 2016

This paper describes a study, funded by the U.S. Department of Energy, to evaluate new, state-of-the-art solar...

CSI RD&D Solicitation 3 Final Webinar: Integrating PV into Utility Planning and Operation Tools
+  |  April 2014

Clean Power Research received a California Solar Initiative (CSI) Research, Development, Demonstration and Deployment...

Behind-the-Meter PV Fleet Forecasting: Results for 130,000 PV Systems in California
+  |  April 2013

Lean how SolarAnywhere® FleetView® is being integrated into CAISO planning and operations tools to provide power...

Integrating PV into Utility Planning and Operation Tools
+  |  February 2013

Clean Power Research received a California Solar Initiative (CSI) Research, Development, Demonstration and Deployment...

Forecasting Output for 130,000 PV Systems in California
+  |  February 2013

Learn how SolarAnywhere® FleetView® is being integrated into CAISO planning and operations tools to provide power...

Behind-the-Meter PV Fleet Forecasting
+  |  October 2012

Learn how SolarAnywhere® FleetView® can be used for behind-the-meter PV fleet forecasting. Presented at the Utility...

Solar Monitoring, Forecasting and Variability Assessment at SMUD
 |  April 2012

This paper summarizes the deployment of a 71 station solar monitoring network in Sacramento, Calif., and its use in...

Photovoltaic (PV) Solar Energy Output Variability Methodologies

These papers present methodologies for cost-effectively predicting the solar power output variability of high-penetration PV fleets.
Spatial and Temporal Variability of Solar Energy
 |  July 2016

This paper summarizes and analyzes recent research by the authors and others to understand, characterize, and model...

CSI RD&D Solicitation 1 Final Webinar: Advanced Modeling and Verification for High Penetration PV
 |  April 2012

In April 2010, Clean Power Research received a California Solar Initiative (CSI) Research, Development, Demonstration...

Determining Storage Reserves for Regulating Solar Variability
 |  November 2011

This paper describes the initial validation of a method of quantifying PV variability by using satellite-derived solar...

Modeling PV Fleet Output Variability
 |  May 2011

This paper introduces a novel approach to estimating the maximum short‐term output variability that an arbitrary fleet...

Short-term Irradiance Variability: Station Pair Correlation as a Function of Distance
 |  March 2011

This article focuses on station pairs, and investigates the correlation of their short-term variability as a function...

PV Power Output Variability: Calculation of Correlation Coefficients Using Satellite Insolation Data
 |  March 2011

This paper describes analytical methods and tools to quantify PV fleet output variability that can be used by utility...

Parameterization of Site-specific Short-term Irradiance Variability
 |  November 2010

This article presents a set of empirical models capable of extracting metrics quantifying the short‐term variability...

PV Power Output Variability: Correlation Coefficients
 |  November 2010

This paper introduces a novel approach to estimate the maximum short‐term output variability that a fleet of PV...

Evaluating PV Fleet Output Variability
 |  December 2009

This presentation describes methods for evaluating the power output variability of PV fleets, and how that information...

Quantifying PV Power Output Variability
 |  May 2009

This paper presents a new approach to rigorously quantify power output variability from a fleet of PV systems, ranging...

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