What is solar energy?

The hottest topic in renewable energy

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    rows of solar panels at sunrise

    Solar energy heats the Earth, performs chemical reactions and produces renewable energy. The sun’s immense power has always been around, but in recent years the adoption of solar power has grown in popularity because it can save homeowners money while also helping the environment.

    Below we’ll discuss how the sun manages to perform all these vital tasks — and how you can use solar energy to enhance your everyday life.

    Key insights

    • Energy harnessed from the sun may be able to power all or part of your home for a fraction of the cost of other energy alternatives.
    • Solar energy is usually collected through photovoltaic panels or concentrating solar-thermal power. Both employ different kinds of solar radiation to create electricity.
    • Investing in solar storage options can make solar energy a more realistic electricity source.

    How does solar energy work?

    The sun emits solar radiation that powers everything from photosynthesis to digestion and breathing. While the sun acts as the generator for almost all everyday functions, the Earth only intercepts an incredibly small percentage of the sun’s total energy.

    Out of this small percentage, even less is absorbed by the Earth and its atmosphere. That being said, the U.S. Department of Energy estimates that the amount of solar energy absorbed by the Earth in just an hour and a half is enough to power the entire planet for a year.

    Using solar panels, you can harness this energy to power simple tasks like your air conditioning, turning on your lights and keeping your food refrigerated — often for cheaper than other electricity alternatives — while also helping the environment.

    How do solar panels work?

    Harnessing the sun’s power with solar panels can make your life easier, but the mechanics are far from simple. There are two main ways to utilize solar energy: photovoltaics (PV) and concentrating solar-thermal power (CSP).

    Photovoltaics (PV)

    Photovoltaic technology is used to create solar panels. Photovoltaics are the small cells located inside solar panels that absorb sunlight and convert it to electricity. An electrical field placed inside the cell causes the electricity to flow. PV makes solar energy a usable renewable resource.

    You can see PV working in homes, businesses and even solar trees, which are art installations that turn renewable energy into an aesthetic sculptural display.

    Concentrating solar-thermal power (CSP)

    Concentrating solar-thermal power systems employ the sun’s heat rather than its light. The heat from the sun is amplified using mirrors and concentrated into receivers that convert this heat into electricity. This creates vast amounts of electricity.

    CSP is typically used strictly at large power plants. The National Renewable Energy Laboratory finds that these technologies are best equipped to provide electricity on a massive scale, powering whole cities, towns and communities.

    » MORE: What is community solar?

    How do I store solar energy?

    According to the U.S. Department of Energy, peak power usage usually occurs during hot summer nights when residential solar units cannot produce power.

    The solution to using solar-generated power at night is solar storage. Energy production can be impacted by various circumstances, including season, inclement weather, shadows and even dirt that builds up on the panels. Storing this energy keeps your solar systems running smoothly despite these unavoidable conditions.

    There are three main types of solar storage: electrochemical storage, thermal energy storage and pumped-storage hydropower.

    Electrochemical storage
    This type of storage uses a battery to keep the energy for an appropriate time. These batteries are similar to those that power your laptop or phone, except they use electricity derived from solar energy. Electrochemical storage is most commonly used alongside PV panels.
    Thermal energy storage
    Thermal energy storage is often coupled with CSP and uses fluid to store solar heat. This fluid is used for heating and cooling but can also create an electric current. The heat created by CSP is used to boil the stored fluid and make steam, which produces electrical power that drives a turbine, much like a normal energy generator.

    These turbines require a large amount of fluid storage, making this option realistic only for large energy facilities.

    Pumped-storage hydropower
    Pumped-storage hydropower also relies on fluid to create an electrical current. Your unused electricity pumps water uphill into a dam or nearby body of water, where the energy is stored. Once you require the electricity, the water flows back down the hill to power a turbine. Like thermal energy storage, pumped-storage hydropower is typically used for large facilities.

    According to the U.S. Department of Energy, this type of storage has been around since the 1890s, but it’s dropped in popularity due to the massive amount of water and prep required to store and use the energy.

    Pros and cons of solar energy

    There are several options for solar energy production and storage, but the key to going solar is finding out if it's suitable for your particular lifestyle and household.

    Solar energy pros

    • Combats climate change: Using solar energy as your primary means of electricity helps combat the negative effects of climate change. Additionally, solar panels do not produce any greenhouse gasses, unlike other electricity alternatives.
    • Beneficial investment: The cost of going solar is gradually decreasing. Solar energy can make your utility bills cheaper, increase the value of your home and qualify you for certain tax benefits. These benefits vary based on your location and type of solar installation.
    • Energy independence: As the prices of fossil fuels and oil continually increase, going solar looks more favorable. The U.S. Department of Energy foresees energy independence creating jobs, and stimulating the American economy.

    » CREDIT WHERE IT’S DUE: How does the federal solar tax credit work?

    Solar energy cons

    • Intermittency: The sun isn’t always shining, and it’s impossible to know when your solar panels will receive the solar energy to power your everyday needs. Solar storage can provide energy for times like these, but once your storage is empty, you’re left with no electricity. This can make solar panels unpredictable and possibly unreliable.
    • Initial investment and installation costs: Solar panels can be expensive to install in relation to other energy sources. The prices of panels and installations vary based on location; doing your research is imperative.
    • Land and space requirements: In order to absorb enough solar energy to suit your electricity needs, solar panels require a large amount of land. To make solar energy a realistic renewable energy source, you also need to take into account energy storage, which also takes up space on your property.

    » MORE: Are solar panels worth it?

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      How efficient are solar panels?

      Most of the sunlight that hits PV panels is lost — the average conversion rate of solar energy to electricity is around 20%.

      » MORE: Solar panel efficiency

      Can solar panels work without direct sunlight?

      Yes. Solar panels produce far more electricity when they’re in direct sunlight, but even when obstructed by rain, snow or dirt, they’re still capable of producing electricity.

      What is net metering, and how does it work?

      Net metering allows solar-powered homeowners to sell extra energy produced from solar panels back to the grid for compensation. Net metering is reportedly only available in 41 states, so make sure you're eligible.

      What is the life span of solar panels?

      The average life span for solar panels is around 25 years. Due to continuous solar innovation, these panels often achieve a greater life span.

      » LEARN: How long do solar panels last?

      Article sources
      ConsumerAffairs writers primarily rely on government data, industry experts and original research from other reputable publications to inform their work. Specific sources for this article include:
      1. U.S. Department of Energy, “ Solar Integration: Solar Energy and Storage Basics .” Accessed June 27, 2023.
      2. U.S. Department of Energy, “ How Does Solar Work? ” Accessed June 27, 2023.
      3. National Renewable Energy Laboratory, “ Solar Energy Basics .” Accessed June 27, 2023.
      4. Energy Information Administration, “ Solar explained: Solar energy and the environment .” Accessed June 27, 2023.
      5. U.S. Department of Energy, “ Benefits of Residential Solar Energy .” Accessed June 27, 2023.
      6. Bonneville Power Administration, “ Intermittent Renewable Energy. ” Accessed June 27, 2023.
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