Solar Resource Maps: A Comprehensive Guide to Harnessing Solar Energy

Solar energy is a rapidly growing industry that holds immense potential for reducing our dependence on traditional fossil fuels. As the demand for renewable energy continues to rise, it is crucial to have access to accurate and reliable solar resource maps and data. These resources provide valuable insights into the solar potential of different regions, enabling individuals, businesses, and governments to make informed decisions about solar energy projects. In this comprehensive guide, we will explore various solar resource maps and data tools available for the United States and other regions, along with the key factors to consider when assessing solar energy viability. 

Understanding Solar Resource Maps and Data

Solar resource maps and data serve as valuable tools for assessing the solar potential of a specific location. They provide information about solar irradiance, which is the amount of solar radiation reaching a particular area. Solar irradiance is typically measured in two forms: Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI). GHI represents the total amount of solar radiation received on a horizontal surface, including both direct and diffuse sunlight. DNI, on the other hand, measures only the direct component of solar radiation that is perpendicular to the sun's rays.

These solar resource maps and data are generated through sophisticated models and calculations based on historical weather patterns, geographical factors, and other relevant parameters. By analyzing these maps and data, individuals and organizations can gain insights into the solar energy potential of a specific area and determine the feasibility of solar energy projects.

The National Solar Radiation Database (NSRDB)

The National Solar Radiation Database (NSRDB) is a valuable resource for accessing solar resource maps and data for the United States and the Americas. Developed by the National Renewable Energy Laboratory (NREL), the NSRDB provides multiyear annual and monthly average maps and geospatial data, including GHI and DNI.

To access the solar resource maps and data from the NSRDB, visit their website and explore the available resources. The NSRDB offers both individual map downloads and the option to download all the maps at once for convenience. These maps can be used in electronic and printed publications with proper citation.

Solar Resource Maps for the United States

The NSRDB offers a range of solar resource maps specifically tailored for the contiguous United States. These maps provide valuable insights into the solar potential of different regions and can be used to assess the viability of solar energy projects. Let's take a closer look at the annual average and monthly average maps for both GHI and DNI.

Global Horizontal Irradiance (GHI) Maps

The GHI maps represent the total solar radiation received on a horizontal surface. This includes both direct sunlight and diffuse radiation. The GHI maps provide valuable information about the solar potential of a specific region throughout the year. By analyzing these maps, individuals and organizations can gain insights into the average solar radiation levels and variations across different months and seasons.

Annual Average GHI Map

The annual average GHI map provides an overview of the average solar radiation levels throughout the year. It helps in understanding the overall solar potential of a specific region and serves as a starting point for assessing the feasibility of solar energy projects.

Monthly Average GHI Maps

The monthly average GHI maps provide a more detailed analysis of the solar radiation variations across different months. These maps use the same color scale and class breaks as the annual average map, allowing for a comparative analysis of the monthly variations relative to the annual average. This information is crucial for understanding seasonal variations and planning solar energy projects accordingly.

Direct Normal Irradiance (DNI) Maps

The DNI maps focus specifically on the direct component of solar radiation, which is the radiation received perpendicular to the sun's rays. These maps provide insights into the direct sunlight available in a specific region, which is particularly important for solar technologies like concentrating solar power (CSP). By analyzing the DNI maps, individuals and organizations can assess the solar potential for CSP projects and determine the most suitable locations.

Annual Average DNI Map

The annual average DNI map provides an overview of the average direct sunlight available throughout the year. This information is essential for assessing the feasibility of CSP projects, which rely on direct solar radiation for generating electricity.

Monthly Average DNI Maps

Similar to the monthly average GHI maps, the monthly average DNI maps showcase the variations in direct sunlight across different months. By comparing these maps with the annual average, one can identify the seasonal variations in direct sunlight and plan CSP projects accordingly.

Geospatial Data for Solar Resource Analysis

In addition to solar resource maps, geospatial data sets are also available for a more detailed analysis of solar energy potential. These data sets are derived from the NSRDB and provide valuable information for understanding solar irradiance at a more granular level.

To access the geospatial data sets, appropriate geographic information system (GIS) software is required. These data sets can be utilized to analyze solar energy potential in specific areas, conduct simulations, and develop accurate models for solar energy projects.

The Global Solar Atlas: A Comprehensive Resource

For a broader perspective, the Global Solar Atlas is an excellent resource that provides solar resource maps and data for various countries and regions worldwide. Published by the World Bank Group and prepared by Solargis, the Global Solar Atlas offers a comprehensive view of solar irradiance and potential across the globe.

The Global Solar Atlas is licensed under the Creative Commons Attribution license (CC BY 4.0), allowing users to download, share, adapt, and use the maps. However, it is mandatory to provide appropriate attribution to The World Bank, the source of the maps, and Solargis, the provider of solar resource data.

Assessing Solar Energy Viability: Factors to Consider

While solar resource maps and data provide valuable insights, several factors should be considered when assessing the viability of solar energy projects. Here are some key considerations:

1. Energy Demand and Usage Patterns

Solar energy projects should align with the energy demand and usage patterns of a specific location. Analyzing the energy consumption trends and identifying peak demand periods can help determine the capacity and design of solar energy systems.

2. Technological Considerations

Different solar technologies, such as photovoltaic (PV) systems, concentrating solar power (CSP), and solar thermal heating and cooling (SHC), have varying requirements and capabilities. Understanding the technological aspects and evaluating their suitability for a particular project is essential.

3. Economic Feasibility

A thorough economic analysis is crucial to determine the financial viability of solar energy projects. Factors such as installation costs, maintenance expenses, potential savings, available incentives, and payback periods should be considered to evaluate the economic feasibility.

4. Regulatory and Policy Environment

The regulatory and policy environment plays a significant role in the successful implementation of solar energy projects. It is essential to understand the local regulations, permitting processes, grid connection policies, and available incentives to ensure compliance and smooth project execution.

5. Environmental Impact

Solar energy projects offer several environmental benefits, such as reducing greenhouse gas emissions and minimizing air pollution. Assessing the environmental impact and ensuring compliance with sustainability goals and regulations is crucial for successful project implementation.

6. Stakeholder Engagement and Collaboration

Engaging stakeholders, including local communities, government agencies, and industry experts, is essential for successful solar energy projects. Collaboration and consultation throughout the planning and implementation stages can help address concerns, ensure support, and foster a positive impact on local communities.

7. Long-Term Performance and Maintenance

Solar energy systems require regular maintenance to ensure optimal performance and longevity. Considering long-term performance and maintenance requirements is crucial to maximize the benefits and return on investment of solar energy projects.

8. Scalability and Future Expansion

Solar energy projects should be designed with scalability and future expansion in mind. Assessing the potential for system upgrades, additional capacity, and integration with other renewable energy sources can help future-proof the projects.

9. Monitoring and Data Analysis

Continuous monitoring and data analysis of solar energy systems enable performance evaluation, early detection of issues, and optimization for maximum energy production. Implementing robust monitoring systems and utilizing advanced analytics can enhance the efficiency and reliability of solar energy projects.

10. Training and Skill Development

Building a skilled workforce and providing training opportunities are essential for the successful implementation and maintenance of solar energy projects. Training programs and skill development initiatives can ensure the availability of qualified professionals and promote the growth of the solar industry.


Solar resource maps and data are invaluable tools for assessing the solar potential of different regions and guiding solar energy project development. By utilizing these resources and considering various factors, individuals, businesses, and governments can harness the power of solar energy to reduce reliance on fossil fuels and contribute to a sustainable future. Accessing solar resource maps, analyzing geospatial data, and collaborating with stakeholders are essential steps toward successful solar energy projects. Embracing solar energy not only offers environmental benefits but also opens up new opportunities for economic growth and energy independence. Let us embrace the power of the sun and pave the way for a brighter and more sustainable future.