The high share of PV energy requires greater system flexibility to address the increased demand/supply imbalance...
Research Timeline
Research Timeline
A chronological listing of more than two decades of Clean Power Research published research.
IRENA SolarCity
This project combines ultra-high-resolution (0.5 meter or 1 meter) Digital Elevation Model (DEM) data and 3D vector...
IEA Task 16-3.5 Report: Firm Power Generation
Grid-connected solar power generation, either dispersed or centralized, has developed and grown at the margin of a...
Inferring PV system specifications from net loads and reconstructing gross loads
The US Energy Information Administration (EIA) estimates that residential PV systems accounted for 61 percent of total...
Inferring PV system specifications from net load
The increasing penetration of grid-connected solar photovoltaics has challenged the existing method of planning and...
Firm PV Power generation for Switzerland
We investigate whether photovoltaics (PV) can effectively and economically contribute to a massively renewable energy...
Firm PV Power Generation in Switzerland
We investigate whether PV can effectively and economically contribute to a massively renewable energy (RE) power...
Nonparametric Temporal Downscaling of GHI Clear-sky Indices Using Gaussian Copula
Small-scale variabilities of solar irradiance are important for many applications. Downscaling approaches need to be...
Enhancing Temporal Variability of 5-minute Satellite-Derived Solar Irradiance Data
Satellite-derived solar irradiance data are known to underestimate temporal variability compared to point measurements...
Update 2022 – A Fundamental Look at Supply Side Energy Reserves for the Planet
Energy on our planet is central to the functioning of our ecosystem and modern human society. This work attempts to...
A Review of Solar Forecasting, Its Dependence on Atmospheric Sciences and Implications for Grid Integration: Towards Carbon Neutrality
The ability to forecast solar irradiance plays an indispensable role in solar power forecasting, which constitutes an...
2021
IMPLICIT STORAGE – Optimally Achieving Lowest-Cost 100% Renewable Power generation
Implicit storage – aka overbuilt and operationally curtailed variable renewable energy (RE) resources – is a...
Quantifying the Solar Impacts of Wildfire Smoke in Western North America
2020 was the most active wildfire season in recent history. This study leverages solar models to quantify the solar...
Least-Cost Firm PV Power Generation: Dynamic Curtailment vs. Inverter-Limited Curtailment
Overbuilding and dynamic curtailment are increasingly acknowledged as central to cost-optimally transforming...
Residual Load Imbalance Mitigation Strategy via Flexible PV Ancillary Services: The Italian Case Study
Large share of solar energy imposes a higher system flexibility to resolve the increased demand/supply imbalance due...
Ultra-High Photovoltaic Penetration: Where to Deploy
While it is widely known that the solar resource is sufficient to meet the world’s energy demand many times over, the...
Making the Cut with a Carbon Elimination Price: The Missing Piece to Bill Gates’ How to Avoid a Climate Disaster Book
In the book How to Avoid a Climate Disaster, Bill Gates begins to address the issue of how much it will cost to...
Italian Protocol for Massive Solar Integration: From Solar Imbalance Regulation to Firm 24/365 Solar Generation
This article describes a progressive strategy to achieve 100% penetration of intermittent renewables at minimal cost....
2020
Observed Recent Trends in the Solar Resource across North America: Changing Cloud-cover, AOD and the Implications for PV Yield
In years recent to 2020, low solar-resource in the Eastern U.S. was observed in the SolarAnywhere® dataset. This paper...
From Firm Solar Power Forecasts to Firm Solar Power Generation an Effective Path to Ultra-High Renewable Penetration a New York Case Study
We introduce firm solar forecasts as a strategy to operate optimally overbuilt solar power plants in conjunction with...
The Value of PV Power Forecast and the Paradox of the “Single Pricing” Scheme: The Italian Case Study
One of the major problem of photovoltaic grid integration is limiting the solar-induced imbalances since these can...
Verification of Deterministic Solar Forecasts
The field of energy forecasting has attracted many researchers from different fields (e.g., meteorology, data...
Italian Protocol for Massive Solar Integration: Imbalance Mitigation Strategies
This article proposes two strategies for the mitigation of power imbalances and related costs resulting from...
2019
Perfect Operational Solar Forecasts: A Scalable Strategy toward Firm Power Generation
We present the perfect forecast concept as both an effective forecast validation metric and an operational strategy to...
Investigations of Site-Specific, Long Term Average Albedo Determination for Accurate Bifacial System Energy Modeling
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
Solar PV system specifications are critical to accurately modeling PV system production (along with high-quality...
EPIC Solar Forecasting Task 3 Final Report: Grid-Connected and Embedded PV Fleet Forecasting Accuracy
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
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
This presentation discusses how probabilistic forecasting enables electric utilities and grid operators to reduce...
Extending Fleet Forecasting Capability into the Probabilistic Realm
This presentation demonstrates how a new approach to PV fleet forecasting can address the problem of artificially high...
Solar+ Homes: If an Integrated Approach Works in a Retrofit Application, New Homes Will Be Even Better
This presentation demonstrates the effectiveness of an integrated approach to electrification of existing and new...
Value of Solar+Storage in Guam
This report presents the results of a distributed-solar valuation performed for the island of Guam. The study used...
Montana Solar Market Assessment
As part of the U.S. Department of Energy’s SunShot Initiative, the Montana Energy Office (MEO) of the Montana...
A Radical Idea to Get a High-Renewable Electric Grid: Build Way More Solar and Wind Than Needed
The famous inventor Edwin Land said, “It’s not that we need new ideas, but we need to stop having old ideas.” He...
Can We Gauge Forecasts Using Satellite-Derived Solar Irradiance?
Satellite-derived irradiance data, as an alternative to ground-based measurements, offer a unique opportunity to...
Overbuilding & Curtailment: The Cost-Effective Enablers of Firm PV Generation
Current thinking considers that PV output curtailment is a last resort measure to be avoided. In this article, we...
2016
Importance of Input Data and Uncertainty Associated with Tuning Satellite to Ground Solar Irradiation
Although the uncertainty of satellite data such as SolarAnywhere® Data has been shown to be low, it can be challenging...
Solar Energy Forecast Validation for Extended Areas & Economic Impact of Forecast Accuracy
This article evaluates the accuracy of solar forecast models, including SolarAnywhere®, as a function of geographic...
2015
Maine Distributed Solar Valuation Study
In support of the Maine Public Utilities Commission's work in 2014-15 to determine the value of distributed solar...
Valuation of Solar + Storage in Hawaii: Methodology
Clean Power Research was engaged by the Interstate Renewable Energy Council, Inc. (IREC) to develop a methodology that...
2013
2014 Value of Solar at Austin Energy
This report and presentation summarizes a Value of Solar® study conducted for Austin Energy in the fall of 2013....
Behind-the-Meter PV Fleet Forecasting: Results for 130,000 PV Systems in California
Lean how SolarAnywhere® FleetView™ is being integrated into CAISO planning and operations tools to provide power...
Behind-the-Meter PV Fleet Forecasting
Grid-connected PV in the U.S. has grown substantially over the past several years and grid operators are increasingly...
The Value of Distributed Solar Electric Generation to San Antonio
This Value of Solar® study was prepared for Solar San Antonio under a Department of Energy SunShot Initiative grant....
Forecasting Output for 130,000 PV Systems in California
Lean how SolarAnywhere® FleetView™ is being integrated into CAISO planning and operations tools to provide power...
Integrating PV into Utility Planning and Operation Tools
This presentation describes how SolarAnywhere® FleetView™ is being used to cost-effectively forecast power output of...
Net Metering: Quantifying Benefits and Sharing Costs
This presentation covers two methods of valuing solar that are currently being considered as alternatives to net...
2012
The Value of Distributed Solar Electric Generation to New Jersey and Pennsylvania
This Value of Solar® study was prepared for the Mid-Atlantic Solar Energy Industries Association (MSEIA) and the...
Behind-the-Meter PV Fleet Forecasting
Learn how SolarAnywhere® FleetView™ can be used for behind-the-meter PV fleet forecasting. Presented at the Utility...
Photovoltaic Incentive Design Handbook
This handbook will help agencies and utilities select, design, and implement incentive programs that best meet...
Solar Monitoring, Forecasting and Variability Assessment at SMUD
This paper summarizes the deployment of a 71 station solar monitoring network in Sacramento, Calif., and its use in...
Reporting of Irradiance Model Relative Errors
Metrics used in assessing irradiance model accuracy such as Root Mean Square Error (RMSE) and Mean Absolute Error...
Predicting Short-term Variability of High Penetration PV
This article evaluates the ability of three operational satellite models (SolarAnywhere® Standard, Enhanced, and High...
Off-Shore Wind and Grid-Connected PV: High Penetration Peak Shaving for New York City
This article presents an experimental evaluation of the combined effective capacity of off-shore wind and...
Solar Power Generation in the US: Too Expensive or a Bargain?
This article identifies the combined value that solar electric power plants deliver to utilities’ rate payers and...
Evaluating Irradiance Accuracy Using California ISO Data: Lessons Learned
This presentation provides the results of a study evaluating the short, medium and long-term accuracy of irradiance...
2011
Determining Storage Reserves for Regulating Solar Variability
This paper describes the initial validation of a method of quantifying PV variability by using satellite-derived solar...
Modeling PV Fleet Output Variability
This paper introduces a novel approach to estimating the maximum short‐term output variability that an arbitrary fleet...
PV Power Output Variability: Calculation of Correlation Coefficients Using Satellite Insolation Data
This paper describes analytical methods and tools to quantify PV fleet output variability that can be used by utility...
Short-term Irradiance Variability: Station Pair Correlation as a Function of Distance
This article focuses on station pairs, and investigates the correlation of their short-term variability as a function...
2010
Parameterization of Site-specific Short-term Irradiance Variability
This article presents a set of empirical models capable of extracting metrics quantifying the short‐term variability...
PV Power Output Variability: Correlation Coefficients
This paper introduces a novel approach to estimate the maximum short‐term output variability that a fleet of PV...
Valuing a Portfolio of PV Investments
This presentation describes the importance of PV output variability as a factor in calculating the value of a fleet of...
Validation of Short & Medium Term Operational Solar Radiation Forecasts in the U.S.
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
This paper presents a study of how PV performance model results are affected when satellite-based weather data is used...
Weather Adjusted Performance Guarantees
This paper describes how to generate more accurate Weather-Adjusted Performance Guarantees for PV systems using a...
Market Transformation Benefits of a PV Incentive Program
Real-life example of the economics of implementing a PV incentive program Download PDF >>>
Quantifying the Cost of High Photovoltaic Penetration
Calculating the cost of energy storage to provide firm capacity on a power grid with high PV penetration. Download PDF...
The CA Net Energy Metering Report: Approach, Results & Implications
The steps required to compute the costs and benefits of electric rates that use net energy metering. Download PDF...
2009
Evaluating PV Fleet Output Variability
This presentation describes methods for evaluating the power output variability of PV fleets, and how that information...
Quantifying PV Power Output Variability
This paper presents a new approach to rigorously quantify power output variability from a fleet of PV systems, ranging...
2008
Solar Sustained Vehicles: A Consumer’s Solution to Protection in an Age of Oil Dependence, Economic Uncertainty, & Global Warming
A consumer’s view of the fuel saving benefits of Solar Sustained Vehicles. Download PDF >>>
Shining on the Big Apple: Satisfying New York City’s Peak Electrical Needs with PV
This presentation describes how measured data was used to evaluate the potential of PV to satisfy the electrical needs...
Expected Performance Based Buydown (EPBB) Incentive Structure: Rationale & Implications
Rationale for using an up-front incentive payment structure Download PDF >>>
Incentive Structure Alternatives
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The Value of Distributed Photovoltaics to Austin Energy & the City of Austin
Quantifies the comprehensive value of distributed PV to Austin Energy. Download PDF >>>
2005
Maximizing the Value of Customer-Sited PV Systems Using Storage & Controls
Enhancing the load management and outage protection attributes of PV to increase the value of customer-sited PV...
2004
Economic Benefits of Performance-Based Incentives
Compares the economic consequences of performance-based and buy-down PV incentives Download PDF >>>
Quick Review of Basic Economics
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Field Validation of the Clean Power Estimator’s Obstruction Analysis Algorithm
This paper validates the Clean Power Estimator obstruction analysis algorithm based on results produced by the Solar...
Are Photovoltaic Systems Worth More to Residential Consumers on Net Metered Time-of-Use Rates?
Examination of the value of PV to residential customers under Time-of-Use rates. Download PDF >>>
2003
Distributed Photovoltaics in New Jersey
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A Simple Method for Consumers to Address Uncertainty When Purchasing Photovoltaics
Should consumers invest in PV now, or wait? Download PDF >>>
Maximizing PV peak shaving with solar load control: validation of a web-based economic evaluation tool
Calculating the value of solar load control for commercial applications using Clean Power Estimator. Download PDF...
Validation of a Simplified PV Simulation Engine
This paper describes and validates a simple PV simulation model capable of predicting average PV output as a function...
Estimator Documentation
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2002
2001
2000
1999
Clean Distributed Resources in the U.S. Residential Market
Examines how PV combined with energy efficiency and cogeneration fuel cells can satisfy the energy needs of the U.S....
Keep the Door Open for Micro-Grids
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A Micro-Grid with PV, Fuel Cells and Energy Efficiency
This article provides an evaluation of the economic potential of a micro-grid composed of PV, fuel cells and energy...
1997
Distributed Generation & Micro-Grids
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Credit Ratings & Photovoltaic Investments
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Integrating Renewable Energy Technologies in the Electric Supply Industry: A Risk Management Approach
Identifies the renewable energy technology risks to utilities, and how to mitigate those risks Download PDF...
Managing Risk Using Renewable Energy Technologies
Explains how owning renewable energy technologies can mitigate risk faced by the electric utility industry Download...
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Blog
Case Study: Rappahannock Electric Cooperative streamlines solar program
Rappahannock Electric Cooperative's (REC) Energy Solutions and Clean Energy team struggled with high solar support call volumes and a labor-intensive interconnection process. To improve their residential and commercial solar programs, REC sought to automate customer...
Unpacking the Inflation Reduction Act part 2: Strategies for electric utilities to effectively scale DER adoption
This is part 2 of a 2-part blog. In Part 1, we discussed the challenges and impact of the Inflation Reduction Act on utilities and energy agencies. In Part 2, we’ll share utility best practices to meet increased DER program demands and demonstrate how Clean Power...