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Best Free Solar PV System Simulation & Design Software
Best Free Solar PV System Simulation & Design Software

Best Free Solar PV System Simulation & Design Software

We’ve researched for Free and Open-source Solar PV Simulation Software and prepared a list of the best one available in the energy market. There are many software available for the design and analysis of Solar PV System, however most of them are not free and costs more than $500 USD for their basic packages. Thanks to U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and Natural Resources Department of Canada for developing these software which are available for free download.

Let’s check out the Best Free Solar PV Simulation Software!

#1 RETScreen – Clean Energy Management Software

RETScreen - Clean Energy Management Software
RETScreen – Clean Energy Management Software

RETScreen allows professionals and decision-makers to quickly find, calculate and optimize the technical and financial viability of potential renewable energy projects. This decision intelligence software platform also allows managers to easily calculate and confirm the actual performance of their facilities and helps find additional energy savings/production prospects. RETScreen Expert, an advanced premium version of the software, is available in Viewer mode completely free-of-charge. The software currently has over 368,000 active users around the globe.

RETScreen is Best for:

  • Energy Technology Engineers
  • Energy Managers
  • Facility Managers
  • Energy Finance Analysts
  • Academics and Researchers on Clean Energy
  • Other clean energy professionals including policy makers and decision makers

Top Features:

  • Benchmarking
  • Bill Importing
  • Budgeting & Forecasting
  • Cost / Use Reporting
  • Emissions Monitoring
  • Energy Price Analysis
  • Greenhouse Gas Tracking
  • Load Forecasting
  • Meter Tracking
  • Risk Management
  • Weather Normalization

RETScreen was initially released in 1998 (21 years ago) and is available in 36 languages.

#2 SAM (System Advisor Model)

SAM (System Advisor Model)
SAM (System Advisor Model)

SAM is a performance and economic model designed to simplify decision making for professionals involved in the renewable and clean energy industry, ranging from project managers and engineers to incentive program designers, technology developers, and academic researchers. A working knowledge of renewable energy technologies and project finance is prerequisite.

Checkout: How Solar Panel Energy Monitoring Systems Work?

SAM estimates a system’s total electricity production in kilowatt-hours (kWh) for the first year based on hourly weather data for a specific location, and physical specifications of the power system components. It then calculates the total production for the following years based on an annual degradation factor, and annual cash flows based on financial and economic inputs to define the levelized cost of energy and other financial metrics.

SAM is Best for:

  • Energy Technology Engineers
  • Project Managers
  • Policy Analysts
  • Technology Developers
  • Academics and Researchers on Clean Energy

The up-to-date version of the SAM software includes performance models for the following renewable energy technologies:

  • Photovoltaic systems, from small residential rooftop to large utility-scale systems
  • Battery storage with Lithium ion, lead acid, or flow batteries
  • Concentrating Solar Power systems for electric power generation, including parabolic trough, power tower, and linear Fresnel
  • Industrial process heat from parabolic trough and linear Fresnel systems
  • Wind power, from individual turbines to large wind farms
  • Solar water heating
  • Geothermal power generation
  • Biomass combustion for power generation
  • High concentration photovoltaic systems

SAM was first developed in 2006 by the US National Renewable Energy Laboratory (NREL), in conjunction with Sandia National Laboratories and in partnership with the U.S. Department of Energy (DOE) Solar Energy Technologies Program.

#3 PVWatts Calculator

PVWatts Calculator
PVWatts Calculator

Another powerful tool by NREL. PVWatts calculates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations.

NREL’s PVWatts Calculator is a web-based application and can estimates the electricity production of a grid-connected roof- or ground-mounted photovoltaic system based on a few simple inputs. To use the calculator, you provide information about the system’s location, basic design parameters, and an average annual retail electricity rate. In addition to these, PVWatts can also calculate the estimates of the system’s annual and monthly electricity production, and an estimate of the value of that electricity.

You can also check out our list of: Top 5 Free CAD & 3D Modeling Software

PVWatts consists of a set of component models to denote the different parts of a PV system. PVWatts performs hourly simulations to estimate the electricity produced by the system over a single year. PVWatts assumes that there are 8,760 hours in a year.

PVWatts is Best for:

  • Home owners
  • Small Business owners
  • Energy Technicians
  • Renewable energy professionals
  • Academics and researchers on clean energy

PVWatts is a cloud based Solar PV System simulation software and was initially released in 2016 (4 years ago).

Bonus tip: We’ve created two interactive maps for World Renewable Energy Generation & World Renewable Energy Capacity that shows the capacity in mega-watts and units generated in gigawatt-hours for each country. These maps uses the data provided by IRENA (International Renewable Energy Agency) as data source. World top renewable energy installed capacity & generating countries, regions and continents table are also included, rink-wise. You can access these renewable energy interactive maps using the links below:

  1. World Renewable Energy Generation Interactive Map
  2. World Renewable Energy Capacity Interactive Map

These maps can help renewable energy engineers, experts and researchers to see the world’s renewable energy data in a visual and more interactive way.


The software listed here are user-friendly (have cool UI), reliable, accurate and have up-to-date databases. In addition to these, many other free and open-source software are available for photovoltaics system simulation and analysis but most of them are discontinued and retired, and thus we don’t mention them here. We will update this list as new software are developed or any changes are made.

Aimal Khan
Aimal Khan is the founder & CEO of Engineering Passion. He is an engineer and has obtained his bachelor's degree in energy engineering from Kandahar University.