Solar Technology Analysis Models and Tools

The following is a list of computer software that can assist in the design of solar energy systems and/or passive solar heating and cooling techniques for buildings. This is not a complete listing of all software products with solar system and passive solar applications. Inclusion or exclusion from this list does not imply in any way an endorsement of the included programs.

Bird Clear Sky Model

Bird Clear Sky Model model is based on comparisons with results from rigourous radiative transfer codes. It is composed of simple algebraic expressions with 10 user provided inputs.

Bird Simple Spectral Model

The Bird Simple Spectral Model computes clear sky spectral direct beam, hemispherical diffuse, and hemispherical total irradiances on a prescribed receiver plane — tilted or horizontal — at a single point in time. C code revised 24 March 2004

DISC Model

DISC Model allows the user supplies hourly average measured global horizontal data. The algorithm uses empirical relationships between the global and direct clearness indices (Kt, Kn) to estimate the direct beam component.

Energy Smart Pools

This computer software Energy Smart Pools was developed by the U.S. Department of Energy for swimming pool installers and/or owners to analyze pool energy consumption and project the potential savings of a variety of energy management measures and solar pool water heating systems. It is designed to run on MS Windows, but will not run on Windows 2000 or later versions.

In My Backyard Tool

The In My Backyard (IMBY) tool estimates the electricity you can produce with a solar photovoltaic (PV) array at your home or business. Homeowners, businesses, and researchers use IMBY to develop quick estimates of renewable energy production at locations throughout the continental United States, Hawaii, and northern Mexico. IMBY uses a map-based interface to allow you to choose the exact location of your PV array. Based on your location, system size, and other variables, IMBY estimates the electricity production you can expect from your system.

Job and Economic Development Impact (JEDI) Model

The Job and Economic Development Impact (JEDI) Models are easy-to-use, spreadsheet based tools that analyze the economic impacts of constructing and operating power generation and biofuel plants at the local and state level. First developed to model wind energy development impacts, JEDI has expanded to offer models that analyze the job and economic impacts of biofuel plants and concentrating solar power, coal and natural gas power plants.

PV-DESIGNPRO

PV-DESIGNPRO simulates photovoltaic system operation on an hourly basis for one year, based on a user selected climate and system design.

PVWatts

PVWatts is an internet accessible tool developed by the National Renewable Energy Laboratory that calculates electrical energy produced by a grid-connected photovoltaic (PV) system for locations within the United States and its territories.

PV Watts Viewer (United States PV Atlas)

A map interface accesses monthly average solar resource information for any given location in the contiguous 48 states. It also provides access to spreadsheets giving average monthly radiation for 14 different types of solar collectors. Data for individual collectors is also available for fixed, flat-plate (photovoltaic) collectors on five different orientations. The PV Watts Viewer and United States PV Atlas were developed by the National Renewable Energy Laboratory (NREL).

Regional Energy Deployment System (ReEDS)

Regional Energy Deployment System (ReEDS) is a multiregional, multitimeperiod, Geographic Information System (GIS), and linear programming model of capacity expansion in the electric sector of the United States. The model, developed by NREL's Strategic Energy Analysis Center (SEAC), is designed to conduct analysis of the critical energy issues in today's electric sector with detailed treatment of the full potential of conventional and renewable electricity generating technologies as well as electricity storage. The principal issues addressed include access to and cost of transmission, access to and quality of renewable resources, the variability of wind and solar power, and the influence of variability on the reliability of the grid. ReEDS addresses these issues through a highly discretized regional structure, explicit accounting for the variability in wind and solar output over time, and consideration of ancillary services requirements and costs. See the ReEDS Web site for more information.

RETScreen

The RETScreen software, provided free-of-charge, can be used world-wide to evaluate the energy production, life-cycle costs and greenhouse gas emission reductions for various types of energy efficient and renewable energy technologies (RETs). Developed by the CANMET Energy Diversification Research Laboratory / Natural Resource's Canada.

SMARTS

SMARTS: Simple Model of the Atmospheric Radiative Transfer of Sunshine requires the user supplies hourly average measured global horizontal data. The algorithm uses empirical relationships between the global and direct clearness indices (Kt, Kn) to estimate the direct beam component. Computations are based on the solar geometry for the hour and clearness indices.

SOLAR-2

SOLAR-2 plots sunlight penetrating through a window with any combination of rectangular fins and overhangs. Also plots hour-by-hour 3-D suns-eye view 'movie' of the building. Prints annual tables of percent of window in full sun, radiation on glass, etc.

System Advisor Model (SAM)

Developed in 2006, the System Advisor Model (SAM) is a performance and financial model designed to facilitate decision making for people involved in the renewable energy industry. SAM makes performance predictions and cost of energy estimates for grid-connected power projects based on installation and operating costs and system design parameters that you specify as inputs to the model. Projects can be either on the customer side of the utility meter, buying and selling electricity at retail rates, or on the utility side of the meter, selling electricity at a price negotiated through a power purchase agreement (PPA).

Solar and Wind Energy Resource Assessment (SWERA) Model

The availability of reliable, accurate, and easily accessible solar and wind energy resource data is critical — and it can greatly accelerate the deployment of these technologies. The Solar and Wind Energy Resource Assessment (SWERA) is a pilot project designed to compile such data in 13 developing countries and to facilitate investments in solar and wind energy projects. The Strategic Energy Analysis Center (SEAC) developed a Geo-spatial Toolkit, which uses a Geographic Information System (GIS) to easily access this data. The SWERA Geo-spatial Toolkit is:

Easy to use — not directed at a technical audience
Allows people with no GIS experience to look at and analyze GIS data
Will be distributed free of charge with resource data to 13 countries that are part of the SWERA project
Can facilitate renewable development in these countries by providing easy access to the resource data
Is being integrated with the project analysis tool HOMER®.

SWERA information can be accessed online - please contact Dan Getman in SEAC with any comments or questions.

Solar Deployment System (SolarDS)

The Solar Deployment System (SolarDS) model evaluates the potential market penetration of solar photovoltaic (PV) technology. SolarDS examines the market competitiveness of Solar PV technologies from the building user's perspective, considering capital costs, electricity prices, as utility rate structures, incentives, and net-metering policies. SolarDS is a spreadsheet/VBA-based model that simulates the hourly price and performance of PV over 216 locations in the United States to derive a national estimate of the potential PV market from 2005 to 2050. Contact Paul Denholm of the Strategic Energy Analysis Center (SEAC) for more information. You can also access "Solar Deployment System (SolarDS) Model: Documentation and Base Case Results" for more on the model.

SolTrace

NREL developed SolTrace—a ray tracing model—to model solar power optical systems and analyze their performance. The model can be used to develop new, complex solar optical designs that previously couldn't be modeled.

SUN_CHART

The solar design software, SUN_CHART, calculates the position of the sun as its apparent position changes from day to day and from latitude to latitude, and performs shading calculations and plots these shading diagrams directly onto a cylindrical sun chart.

SunPath (Version 3.2)

SunPath is a fully MS Windows-based implementation of the popular SUNPATH 2.0, an MS DOS application allows the user to select latitude and longitude coordinates for a site of interest and then determine the position in the sky of the center of the sun for any day of the year and time of day, or for a sequence of days and times.

Sun or Moon Altitude/Azimuth Table for One Day

A website of the U.S. Naval Observatory's Astronomical Applications Department, which provides altitudes and azimuths for the sun for locations in the USA. This provides a simple way to determine if a landscape feature will shade a potential solar collector site.

Crosscutting Analytical Tools

The following is a list of models and tools that can assist in learning more about our main renewable energy technologies and their uses. Most of these tools can be applied on a global, regional, local, or project basis.

Technology Deployment

Visit the Modeling and Tools for Project Engineering website for more information.

2011 Renewable Energy Data Book

The 2011 Renewable Energy Data Book provides facts and figures on energy in general, renewable electricity in the United States, and global renewable energy development and investments. Rich graphics and depth and breadth of data make the Data Book series among the most popular items on NREL.gov.

Cost of Renewable Energy Spreadsheet Tool (CREST)

The Cost of Renewable Energy Spreadsheet Tool (CREST) is an economic cash flow model designed to enable PUCs and the renewable energy community assess projects, design cost-based incentives (e.g., feed-in tariffs), and evaluate the impact of tax incentives or other support structures. CREST is a suite of three analytic tools, for solar (photovoltaic and solar thermal), wind, and geothermal technologies, respectively.

Distributed Generation Technology Costs and Performance Data

Recent cost estimates for distributed generation (DG) renewable energy technologies are available across capital costs, operations and maintenance (O&M) costs, capacity factor, and levelized cost of energy (LCOE). Where available, links to utility-scale and DG data are available under the tab headings. The LCOE tab provides a simple calculator for both utility-scale and DG technologies that compares the combination of capital costs, O&M, performance, and fuel costs.

Geographic Information System

This site provides dynamically generated maps of renewable energy resources that determine which energy technologies are viable solutions in the United States. The National Renewable Energy Laboratory analyzes the resources and inputs the data into the GIS—Geographic Information Systems.

Green Power Network

The Green Power Network (GPN) provides news and information on green power markets and related activities. The site provides up-to-date information on green power providers, product offerings, consumer protection issues, and policies affecting green power markets. It also includes a reference library of relevant papers, articles and reports. The Green Power Network is operated and maintained by the National Renewable Energy Laboratory for the U.S. Department of Energy.

HOMER® Model

HOMER®, the micropower optimization model, simplifies the task of evaluating design options for both off-grid and grid-connected power systems. When you design a power system, you must make many decisions about the configuration of the system: What components does it make sense to include in the system design? How many and what size of each component should you use? How do the costs and environmental impacts of different system designs compare? The large number of technology options, range of technology costs, and variable availability of energy resources make these decisions difficult to make. The HOMER® model's optimization and sensitivity analysis algorithms make it easier to evaluate the many possible system configurations. For more information, visit the HOMER Energy website. You also can access a fact sheet about this unique tool. Contact developer for more information.

Hybrid2

The Hybrid2 code is a user-friendly tool to conduct detailed long-term performance and economic analysis on a wide variety of hybrid power systems.

Hydrogen Deployment System (HyDS)

The Hydrogen Deployment System (HyDS) model analyzes the transition to a hydrogen economy. It costs out numerous pathways — from production to distribution — finding the most economic mode for hydrogen to be delivered in a user-defined region. It integrates an intercity optimization algorithm, which considers economy-of-scale of production, transportation, and delivery — as well as the trade-offs between centralized and forecourt hydrogen production. Given price projections for gasoline, natural gas, and other feedstocks, the HyDS ME produces a supply curve reflecting the most economic pathway for hydrogen to be delivered. Contact Nate Blair of the Strategic Energy Analysis Center (SEAC) for more information.

Open EI's Transparent Cost Database

The Transparent Cost Database collects program cost and performance estimates for EERE technologies in a public forum where they can be viewed and compared to other published estimates. The database includes literature on technology cost and performance estimates (both current and future projections) for vehicles, biofuels, and electricity generation. All data are downloadable for full transparency.

REFlex

REFlex is a reduced form dispatch model that evaluates the limits of variable renewable generation as a function of system flexibility. It can also evaluate the role of enabling technologies such as demand response and energy storage. It is an updated version of the PVFlex model described in the following articles: "Evaluating the Limits of Solar Photovoltaics (PV) in Traditional Electric Power Systems," by Paul Denholm and Robert Margolis, NREL Report No. JA-640-41459; doi:10.1016/j.enpol.2006.10.014 and "Evaluating the Limits of Solar Photovoltaics (PV) in Electric Power Systems Utilizing Energy Storage and Other Enabling Technologies," by Paul Denholm and Robert Margolis, NREL Report No. JA-6A2-45315. doi:10.1016/j.enpol.2007.03.004

RET Finance

RETFinance is a levelized cost-of-energy model, which simulates a detailed 20-year nominal dollar cash flow for renewable energy projects power projects including project earnings, cash flows, and debt payment to calculate a project's levelized cost-of-electricity, after-tax nominal Internal Rate of Return, and annual Debt-Service-Coverage-Ratios.

Regional Energy Deployment System (ReEDS)

Renewable Energy Technology Characterizations (1997)

The Renewable Energy Technology Characterizations describe the technical and economic status of the major emerging renewable energy options for electricity supply. These technology characterizations represent the best estimates of the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI) regarding the future performance and cost improvements expected for these technologies as a result of continuing research and development (R&D) and development of markets for renewable energy through the year 2030. The Renewable Energy Technology Characterizations are copyrighted, but permission is granted for unlimited copying for noncommercial use.

SERA (Scenario Evaluation, Regionalization & Analysis)

The Scenario Evaluation, Regionalization and Analysis (SERA) model is a geospatially and temporally oriented infrastructure analysis model that determines the optimal production and delivery scenarios for hydrogen, given resource availability and technology cost. Given annual H2 demands on a city-by-city basis, forecasts of feedstock costs, and a catalog of available hydrogen production and transportation technologies, the model generates "blueprints" for hydrogen infrastructure build-out that minimize the overall net-present-value of capital, operating, and feedstock costs for infrastructure networks that meet the specified demand profiles. The model represents production facilities and pipelines at the level of individually geolocated components, while it treats truck and rail transportation at an aggregate level. Intra-urban locations of dispensing stations and of hydrogen production for stationary applications are generated using a geospatial statistical model that matches empirical distributions of such facilities. Prior to October 2009, SERA was know as the Hydrogen Deployment System Modeling Environment (HyDS-ME).

Stochastic Energy Deployment System (SEDS)

The Stochastic Energy Deployment System (SEDS) model is a capacity-expansion model of the U.S. energy market. The model uses five-year time periods from 2005 to 2050. SEDS can be operated either deterministically or stochastically. When operated deterministically, SEDS uses a single value instead of the input-probability distributions for the uncertain parameters. In this mode, the results are immediate and informative, in terms of how the model responds to different inputs and assumptions. When operated stochastically, SEDS uses Monte Carlo simulations to make a number of sweeps through the time period. In each sweep, the random variables are sampled using a Latin Hypercube approach that improves on a standard Monte Carlo simulation. SEDS is being developed with a commercially available software package, Analytica, designed to facilitate the development of stochastic models (for more information on Analytica, visit Lumina). Contact Emily Newes of the Strategic Energy Analysis Center (SEAC) for more information.

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