Which Region of the United States Receives the Greatest Sun Radiation?

It’s no secret a solar system can only perform well if it receives enough sunlight. You may produce two times more electricity in sunny states than in cloudy states. It sounds unfair, but it is what it is: you must consult with a solar energy map before taking action.

A solar energy map – also known as a solar energy potential map – tracks the region’s solar resources, including the number of solar hours you should expect. This, in turn, helps you understand the amount of energy you may get and the feasibility of installation in general (for example, southwestern states are considered the best region for installing solar panels).

With no further ado, let’s dissect solar radiation and sun hours maps.

Can You Detect Solar Radiation?

Only a small portion of the Sun’s power – around 9.5 × 10 25 W – reaches the Earth. Luckily, not only can we detect solar radiation, but we can turn it into electricity with impressive efficiency and, with the help of a solar energy map, decide whether installing a solar panel system makes sense in any given place.

  • The solar energy power on Earth is set at around 1000 W/m2 on a sunny day. Radiation reaches us through direct solar radiation (from the Sun), diffuse radiation (scattered in the atmosphere), and reflected radiation, all of which can be measured individually (for the operation of a solar system, though, a general measurement is sufficient).

To understand how much energy a particular house needs, use one of the devices from the table.

Pyrheliometer (Measures Direct Radiation) Pyranometer (Measures General Radiation for waves of any length)
Measures the amount of heat formed when solar radiation is absorbed Measures the difference in temperature between a bright and dark surface

Besides pyrheliometer and pyranometer, there is also a solar radiation recorder, which calculates the average value of the time when sunlight hits the system. The disadvantage of the recorder is a relatively high error margin, but it’s still a great solar map helper.

Where Can I Get Data for Measuring the Performance of My Solar System?

To measure your solar system’s performance, you need to measure solar insolation.

  • Solar insolation is the instantaneous radiation received by an object in a specific period of time, kWh/m/day. You can get it from solar maps USA.

For large industrial installations, solar irradiance values should be used. Radiation is also measured globally in the whole region and reflects the values on the solar power map.

It is also important to understand the peak hours of sunshine, which characterize the light intensity in a certain area for each kWh/m/day. In the US, the average peak number of active hours of sunshine is between 3 and 5, but these can vary greatly even among states. To estimate the amount of sunlight in your area, use a sun-hours-per-day map.


Likewise, you can use numerous online websites that estimate the average solar insolation by state. The most authoritative website is the official solar insolation map by National Solar Radiation Database (NSRDB), which you can use to determine insolation, the number of peak hours of sunshine, the level of radiation, and other parameters.

Use this particular United States solar map before investing in a private or industrial solar system.

What States Produce the Most Electricity from Solar Energy?

California has the largest solar power capacity in the United States (the total for the second quarter of 2022 was over 37 gigawatts), which you can also check on the USA sunshine hours map. Accounting for 30% of all solar energy in the US, California takes the lead because of favorable climatic conditions and market factors.

Texas is the runner-up with its numerous solar power plants producing around 15 Gigawatts. You can check it on the US solar radiation resource maps.


Source: www.renewableenergymagazine.com

Why Has the Consumption of Solar Energy Increased?

The two main prerequisites for this increase in solar energy consumption are the reduction in the cost of installations and a large number of sunshine hours, as shown on the US solar map. In some states, solar energy accounts for a large part of the energy mix, as illustrated on the solar map USA.

What Are the Three Types of Solar Radiation?

Per the NSRDB solar radiation map, there are three main types of solar radiation:

  1. Visible light. Visible light has the lowest frequency in red, orange, yellow, green, and blue and the highest frequency in indigo and violet. It is its level that can be assessed using the insolation map.
  2. Infrared light. Infrared light is invisible to the human eye, but we can feel it. Infrared light emits heat, just like most living organisms do.
  3. Ultraviolet light. Ultraviolet light is not visible to the human eye and is the only dangerous type of radiation, causing pigments and burns.

There are also other types of radiation, but they account for 1% only.

What Solar Insolation Maps Data Is Important for Solar Systems?

To build a solar panel efficiency map, you need:

  1. Direct Normal Illumination (DNI). Direct Normal Illumination is radiation perpendicular to the rays that travel in a straight line from the sun and are concentrated at one point on the surface. DNI can be adjusted and increased depending on the installation of the solar system. The data is available on solar irradiation maps.
  2. Diffuse Horizontal Irradiance (DHI). Diffuse Horizontal Irradiance is scattered horizontal radiation that falls on a unit area and does not hit it at the right angle. The indicator can be estimated on the NSRDB website in the solar zones map.
  3. Global Horizontal Illumination (GHI). Global Horizontal Illumination is radiation of short wavelengths obtained by a surface horizontal to the ground. To estimate the GHI level, look at the solar radiation map USA.

In the solar efficiency map, you can also evaluate meteorological data that affect the amount of received solar energy.

Do Gamma Rays from the Sun Ever Reach Humans on Earth?

About 95% of all solar radiation passes through the so-called optical window, which is the visible part of the spectrum to which parts of the infrared and ultraviolet waves are adjacent. At the same time, when they pass through the layers of the atmosphere, all the action of gamma and other rays weakens to the degree that 98% of ultraviolet radiation never reaches Earth. Only infrared radiation and visible light can travel almost without a loss (a small amount of them is absorbed by the dust and surrounding gases).

  • Gamma rays cannot reach us or cause health problems because they simply do not leave the surface of the Sun. All gamma rays are concentrated inside the Sun to keep it running. While some of them may get into the outer layers, they are converted to ultraviolet, infrared, and visible light.


Source: svs.gsfc.nasa.gov

The total annual radiation dose is only around 0.3 m3v/year, with possible fluctuation depending on the geographical location and changes during the year (check it on the solar irradiance map). Even strong flares occurring on the Sun cannot send gamma rays to Earth.

Make Smart Solar Decisions with Solar Data

US solar resources data and solar power maps make it easy to make personal and business decisions. Relying on data from a solar potential map, you can understand whether a solar panel system can be viable in your locality and how much time it will take to pay off.

Related Blog Posts


Is Solar Worth It Today, Or Should You Wait?

As of 2023, roughly 5% of U.S. single-unit households had solar systems. This market ...
A solar panel maintenance specialist with a tablet in his hand examining the panels

How Does Tesla’s Powerwall Work?

Living in a time of rapid weather changes that cause power outages and ever-rising ...
Tesla Powerwall batteries installed on a residential building in countryside.

Options for Financing Solar Panels

The energy environment is quickly changing due to solar energy, a beacon of ...
Options for Financing Solar Panels - 1 (1)

Solar Panel Incentives in Texas

Solar energy has become increasingly viable as the emphasis on renewable energy sources ...
Large plots of land with solar panels in Texas.

Tesla Solar Roof: Is That Investment Worth It?

The demand for sustainable energy is on the rise as traditional energy sources become ...

Solar Heating System: Comparison of Solar Energy vs Oil and Gas

In the quest for environmentally friendly energy options, the world has seen a notable ...
Show next

Andy Worford
Andy Worford

Andy is a Founder, Chief Content Officer, regular contributor, and idea generator behind Solar Power Systems. He is well-versed in various aspects of solar energy, including photovoltaic systems, solar policy trends, and green technology innovations.

We will be happy to hear your thoughts

Leave a reply

Solar panel installation tips