Our team atengineering passionhas researched free and open source solar design software tools that can be used to design and simulate residential and commercial solar power systems. While there are many tools for solar energy (PV) system design and analysis, most of them cost more than $500 for their basic packages alone.
That's why we've put together this list of free solar panelsEnergy software, details on their best features and who they are for, and to help you choose the perfect design tool to accurately plan and simulate your projects.
As a solar energy designer, I know how important it is to design systems that are energy efficient and cost effective. This is why this software is so essential for any solar designer, planner, or sales consultant to draft accurate proposals for potential customers who are making the switch to solar energy.
So, let's dive into some important information about solar PV design and simulation software and learn a little more about what they are used for, how to choose one, and the key stages in PV system design.
What is solar design software used for?
Solar design software is used to design and model solar photovoltaic (PV) systems. They are also used to analyze the performance of PV systems. It helps design the system by determining the size, options and specifications of the various components in a solar power system such as solar panel array, PV inverter, charge controller and battery bank and calculates system losses.
The solar design software also determines the effects of different orientations and tilt angles on the performance of the system, as well as global factors such as shading losses.
A key feature of solar design software includes the ability to calculate the cost and payback time of residential and commercial projects.
Essentially, solar design software helps engineers design efficient yet affordable on-grid or off-grid solar PV systems.
What are the advantages of solar design software?
Solar-PV-DesignSoftware allows energy engineers and planners to perform many tasks and calculations very easily. Without them, these calculations would have been time-consuming. The main advantages of using solar PV design and simulation software are:
- It can determine the size of various components in a solar photovoltaic system. Such as solar panel array, inverter, charge controller, battery storage system and so on.
- It calculates the effect of different orientations and tilt angles on performance in different months. The calculation takes global factors such as shading losses into account.
- It can help to calculate the power generation and the energy yield of a solar PV system at different times of the year.
- It helps determine the cost-benefit analysis for developing an effective yet affordable system.
- Solar PV software can help create a report for a project or plan to fulfill the intention of designing a solar power system.
What are the main features of a solar design software?
A good solar design and simulation software should have the following characteristics:
- User friendliness:The first characteristic of good solar design software is its ease of use. It should be easy to understand and use for both engineers and technicians.
- Flexibility:This is another important feature that determines the usefulness of a solar system design tool. It helps determine the size, number, and type of each component used in the photovoltaic system. This allows the performance of the system to be optimized.
- Accuracy:The solar energy software must be accurate in determining the various factors. Such as energy yield, number of panels (PV modules), size of inverter and so on.
- User-friendly:Software for planning photovoltaic systems should be user-friendly. In this way, users can easily achieve the desired results after entering the necessary data.
- Reporting:A good solar PV design software produces detailed reports. Reports help determine the components needed to design a solar power system. They also help determine and summarize system energy losses and costs. The report also includes project information such as project name, location, description, etc.
- Compatibility:A good solar design software should be compatible with different operating systems. Like Linux, Windows and Mac or alternatively be accessible via any web browser.
Important phases when planning a photovoltaic system

The planning of a photovoltaic system consists of 4 main phases:
- System-Design
- sizing
- performance analysis
- economics
System-Designincludes the collection of location data. This data includes insolation, shading analysis, and utility connection requirements.
The second step is thesizing processwhere the size of each component of the PV system is identified. Other parameters such as battery capacity or inverter capacity are also determined. This ensures that enough electricity is produced to meet the household's energy needs at different times of the day and year.
Theperformance analysisHere the designed system is simulated using solar PV modeling software.
Finally, the final step is determining theeconomicsfrom the project. In this phase, a thorough study of the economics and feasibility for the construction and commissioning of the solar PV system should be carried out.
Best free solar PV system design and simulation software
Now you have an understanding of the benefits and features of solar design software. Let's look at the listBest free solar PV system design and simulation software:
#1 RETScreen - Clean Energy Management Software
RETScreen enables professionals and decision makers to find, calculate and optimize the technical and financial feasibility of potentialsrenewable energyprojects. This decision intelligence software also enables managers to easily calculate and confirm the actual performance of their assets, helping to find additional energy savings/production perspectives.
RETScreen Expert, an enhanced 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 world.
When I was studying at a power engineering college, I used RETScreen quite a bit. RETScreen was very useful to me when designing and testing my renewable energy projects back then. RETScreen offers a whole range of functions that can help in the design and verification of energy projects.
RETScreen software is best for:
- Renewable Energy Engineers
- energy manager
- Facility Manager
- energy financial analysts
- Researchers and students for clean and sustainable energy
- Other clean energy professionals including politicians and decision makers
Also read:What can solar energy be used for?
Top-Features:
- Benchmarking
It can help you compare your energy efficiency with other similar facilities around the world.
- Invoice import
Managers can import their energy bills into the software for financial analysis.
- Budgeting & Forecasting
With its built-in financial analysis tools, it can help energy professionals determine the best financing option for their renewable energy project.
- Cost/Usage Reports
It provides a detailed cost and usage report for each facility.
- Emission Monitoring
The software helps to determine the emissions of greenhouse gases caused by the production, consumption and transport of energy.
- energy price analysis
This function can help to compare energy prices. It can be helpful to make decisions about new renewable energy investment projects like a solar power plant.
- greenhouse gas tracking
It can help track emissions caused by the production, consumption, and transportation of energy.
- load forecast
The software provides facility managers with forecasts of actual power consumption. It helps them plan for production bottlenecks.
- risk management
The software offers facility managers the opportunity to proactively manage risks. And improve the energy efficiency of your system.
- weather normalization
RETScreen combines current weather data with information on energy consumption. It helps normalize the impact of weather variations on performance.
RETScreen was originally released in 1998 (23 years ago) and is available in 36 languages.
Click here to download RETScreen.
#2 SAM (System Advisor-Modell)
SAM is a performance and economic model. It is designed to simplify decision-making for professionals working in the renewable and solar industries, from project managers and engineers to academic researchers.
Working knowledge of renewable energy technologies and project finance is a prerequisite for using SAM to get the most benefit from all the advanced features of the solar tools.
Also read:How do solar panel energy monitoring systems work?
SAM estimates the total power generation in kilowatt hours (kWh) for the first year based on hourly weather data for a given location and physical specifications of the power system components.
It then calculates the total energy production for the following years based on an annual deterioration factor and annual cash flows based on financial and economic inputs to define the levelized cost of energy and other financial metrics.
My personal experience with SAM has been modeling residential rooftop photovoltaic systems with battery storage systems. I also found it to be an excellent design tool that was easy to use to model a variety of renewable energy systems.
SAM is best for:
- Power Engineering Engineers
- project manager
- policy analysts
- technology developer
- Researchers and students for clean and sustainable energy
The latest version of SAM (version 2020.11.29) includes performance models for the following renewable energy technologies:
- Photovoltaic systems, from small residential rooftop systems to large utility-scale systems
- Battery energy storage with lithium-ion, lead-acid or flow batteries
- Concentrating solar power systems for power generation. Including parabolic trough, power tower and linear Fresnel
- Industrial process heat from parabolic trough and linear Fresnel solar systems
- Wind power, from the individual turbine to the large wind farm
- Solar water heating
- Geothermal power generation
- Biomass combustion to generate electricity
- Highly concentrated photovoltaic systems
SAM was first developed in 2006 by the US National Renewable Energy Laboratory (NREL). It was developed in collaboration with Sandia National Laboratories and in partnership with the US Department of Energy's (DOE) Solar Energy Technologies Program.
As one of the most well-known and respected solar design tools, SAM has over 190,000 users from countries around the world, about 50% of which are based in the US. [This includes users of PVWatts, which also falls under the SAM umbrella]
Click here to download the SAM software.
#3 PVWatt Calculator
Another powerful solar design tool from NREL. PVWatts calculates the energy production and costs of grid-tied PV systemsEasily develop estimates of the performance of a potential solar PV system worldwide.
NREL's PVWatts Calculator is a web-based application. It can estimate the electricity production of a grid-connected rooftop or ground-mounted photovoltaic system based on a few simple inputs.
How to use the PVWatt calculator?
PVWatts is a set of component models used to denote the different parts of a PV system. To use the calculator, just enter some input information. This information includes location, basic design parameters, and an average annual retail electricity price.
PVWatts can also estimate annual and monthly electricity production and its monetary value.
I highly recommend PVWatts. It is a free and easy-to-use web app for solar PV system simulation and design. I've used PVWatts to run quick simulations of solar energy projects before actually building them. And PVWatts has been very accurate and helpful. Especially in terms of estimating the energy production for my solar projects.
PVWatt is best for:
- energy engineers
- homeowner
- small business owner
- Energy technicians & solar professionals
- Experts in renewable energy
- Researchers and students for clean and sustainable energy
PVWatts is a cloud-based solar PV system software and was first released in 2016 (5 years ago).
Click here to access the PVWatt calculator.
Also read:Can a solar panel charge a power bank? Choose the right charger.
Bonus-Tipp:We have created two interactive maps for World Renewable Energy Generation & World Renewable Energy Capacity showing capacity in megawatts and units generated in gigawatt hours for each country. These maps use the data provided byIRENA(International Renewable Energy Agency) als Datenquelle.
A complete list of the world's largest installed renewable energy capacity and the producing countries, regions and continents is included. You can access these interactive renewable energy maps using the links below:
- Interactive world map for renewable energy generation
- Interactive map of global renewable energy capacity
These maps can help renewable energy engineers, experts and researchers to view the world's renewable energy data in a visual and more interactive way.
frequently asked Questions
What Does a Solar PV Designer Do?
A solar PV design engineer is responsible for determining the various components required to build a solar power system, such as: B. the size of the solar modules, number and capacity of the PV inverter, charge controller andbattery storageInstallation.
To design a solar power system, engineers use software to calculate costs and benefits. Then they can decide about it. Their primary mission is to design and install efficient yet cost-effective solar energy systems for residential and commercial use.
What are the key design components of solar energy (PV) systems?
The key design components that require accurate calculation for solar energy (PV) systems are:
- Assessment of the resources of solar radiation (irradiance).
- Load estimation (load profile)
- Dimensioning of the solar system
- Dimensioning of the inverter
- Selection of monitoring devices for PV systems
- Dimensioning of solar energy storage
- Selection of shelving and assembly equipment
- System Integration
For a solar project, all of these design component calculations must be done with losses in mind. They appear in different parts of the system, like the losses in an inverter (DC to AC conversion).
Which solar PV software works on a macOS?
You can use both SAM and PVWatts solar system design software on your Mac computer. SAM is desktop software that runs on Windows, Mac and Linux. PVWatts is a web app and can therefore be used on any computer, tablet or smartphone with an internet browser.
The RETScreen application is currently only available for Windows operating systems.
What information is used by solar energy software for planning PV systems?
The types of inputs required by a solar energy software include the location of the site, the total load, the type of PV system (grid-connected or off-grid), the brand selection of various system components, and the cost of electricity.
All programs have different entrances. For example, PVWatts calculates electricity production for grid-connected systems. It relies on input data including the system's location, basic design parameters and an average annual retail electricity price.
Are BlueSol, PVSyst, HOMER and Helioscope software available for free?
The software BlueSol, PVSyst, HOMER and Helioscope cannot be used free of charge. They are commercial solar energy design software. However, some of them offer student and startup licenses at reduced prices or a limited free trial.
What is the difference between PVsyst and Helioscope software?
Both PVsyst and Helioscope are great solar energy design software. They can be used to estimate the performance of on-grid, off-grid, and battery storage system designs.
The only difference is that PVsyst has more features to design a small to medium sized solar PV system than Helioscope. PVsyst offers many built-in tools to design a solar energy system and help you with PV layouts. But unlike PVsyst, Helioscope has a more user-friendly graphical user interface. It also offers support for Google Earth and SketchUp. Helioscope also offers 3D modeling and 3D object design capabilities for solar designers.
bottom line:
Solar energy is an abundant source of clean energy.solar cell technologyuses solar energy to generate electricity.Many products can be powered by solar energylike smartphones, wearables to solar dryers, freezers... Solar PV simulation software can help in the design and simulation of a PV system before actually building it. They can also help you estimate project costs.
The software listed here is user-friendly, reliable, accurate and has up-to-date databases. Besides that, some other free and open source software for simulation and analysis of PV systems are available. But most of them are no longer maintained or outdated, so we didn't include them here.
engineering passionwould also like to thank the US Department of Energy's National Renewable Energy Laboratory (NREL) and the Canadian Department of Natural Resources for developing this software, which is a free download.
We continually update this list as new solar power system software is developed or changes are made to existing software.