What Is A Form Of Energy Emitted By The Sun?

Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants, and artificial photosynthesis. Solar energy originates from nuclear fusion reactions deep within the Sun’s core, where immense pressure and temperature convert hydrogen into helium and release solar energy in the process.

Solar energy is considered a renewable energy source as it comes from an essentially infinite supply. With concerns over climate change and depletion of finite fossil fuel reserves, solar power has emerged as a promising clean energy resource. Today, solar energy provides just a small fraction of global energy needs, but it has tremendous potential to replace fossil fuels and power the world with clean, renewable energy.

History of Solar Power

Humans have utilized the sun’s energy for thousands of years. Ancient cultures used passive solar design for heating and lighting homes and buildings. The Greeks and Romans designed their architecture to maximize sun exposure. In the 7th century BCE, magnifying glasses were used to concentrate the sun’s rays to make fire.

In 1839, French physicist Edmond Becquerel discovered the photovoltaic effect while experimenting with metal electrodes in electrolyte solutions. He found that certain materials generated small amounts of electric current when exposed to light. Over the next hundred years, improvements were made in solar technology, leading to the invention of the first modern photovoltaic solar cell in 1954 by Bell Laboratories.

During the energy crisis in the 1970s, photovoltaic solar technology gained significant attention and investment as a renewable energy source. Major advancements in manufacturing and materials brought down costs dramatically. Today, solar power is one of the fastest growing energy sources due to improvements in efficiency and government incentives.

How Solar Energy Works

Solar energy is derived primarily from the photovoltaic effect or the collection of heat from sunlight. The photovoltaic effect refers to the ability of certain materials to generate an electric current when exposed to sunlight. When photons from sunlight hit these photovoltaic materials, their energy gets transferred to electrons in the material, causing the electrons to break free and flow as an electric current. This current can then be captured and used to power electrical devices or fed into the grid.

Common photovoltaic materials used today include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide. Solar panels are made up of many individual solar cells, which are constructed from these photovoltaic materials.

Solar thermal technologies use sunlight to directly heat water or other fluids that can then be used for domestic hot water, space heating, or to drive generators to produce electricity. Solar thermal collectors, such as parabolic mirrors or troughs, concentrate sunlight onto receptacles filled with heat transfer fluid. The heated fluid is then piped to a thermal storage tank or to directly heat water or spaces.

Applications

Solar energy is used in many applications to harness the sun’s energy. The most common applications include:

Solar Panels for Electricity

Solar photovoltaic panels convert sunlight directly into electricity using semiconducting materials. Solar panels are mounted on rooftops or ground installations to generate power for homes, businesses, and the electric grid. Rooftop solar provides clean on-site power generation and solar farms provide utility-scale renewable electricity.

Solar Water Heating

Solar thermal collectors heat water for domestic, commercial, or industrial use. Solar hot water systems circulate heat transfer fluids through collectors and a storage tank to provide hot water and space heating.

Concentrated Solar Power

Concentrated solar power (CSP) systems use mirrors or lenses to concentrate sunlight to heat a receiver containing a heat transfer fluid. The high temperature fluid is used to drive a turbine to generate electricity. CSP allows energy storage by heating molten salt to run generators when direct sunlight is not available.

Advantages

Solar energy has many benefits that make it an appealing renewable energy source. Here are some of the main advantages of solar energy:

Renewable and abundant: Sunlight is a virtually inexhaustible resource. The amount of solar energy that hits the Earth’s surface in just one hour is enough to power the entire world for a year. As a renewable resource, solar energy does not face depletion issues like fossil fuels.

Reduces fossil fuel reliance: Generating energy from the sun reduces our dependence on finite resources like coal, oil and natural gas. Widespread adoption of solar power will help prolong the world’s supply of non-renewable fuels.

Lower environmental impact: After solar panels are installed, they generate clean electricity without emitting pollutants or greenhouse gases. Solar energy has a much smaller carbon footprint than traditional energy sources. Using solar can help combat climate change.

Disadvantages

While solar energy has many benefits, there are some key disadvantages to consider as well:

Intermittency requires storage: Unlike traditional fossil fuel power plants which can provide electricity at any time of day or night, solar energy relies on sunshine and is not available at night or on cloudy days. This intermittency means solar power requires energy storage solutions like batteries to provide a steady supply of electricity.

High upfront costs: Installing a residential solar panel system can cost $10,000-$30,000 upfront, which is a major investment compared to utility electricity. While solar can provide long-term savings on energy bills, the initial cost is prohibitive for many households.

Low efficiency: Most solar panels on the market today operate at 15-20% efficiency, meaning they convert only a small fraction of the sun’s energy into usable electricity. More efficient solar technologies are being researched, but have not reached large-scale adoption yet.

Solar Potential

Solar energy has significant potential given the amount of sunlight the earth receives. Some areas of the world receive more annual sunlight than others, making them optimal for solar power generation.

The highest solar resources are located in arid regions near the equator, such as the southwestern United States, northern Africa, the Middle East, Australia, and much of South America. These regions average around 6-8 kilowatt-hours per square meter per day of sunlight. Even areas with lower solar potential, such as Canada, Russia and Europe, still receive roughly 3 kWh/m2 per day and can generate significant solar power.

Estimates for the total global solar energy potential range from 25,000 to 50,000 terawatt-hours (TWh) per year. For perspective, worldwide electricity consumption is currently around 22,000 TWh. So even with today’s technology, solar power could supply several times more energy than the world currently uses.

Growth and Adoption

Solar energy capacity has expanded rapidly over the past decade. In 2010, the world had about 40 gigawatts (GW) of solar PV installed. By the end of 2021, global solar PV capacity soared to over 1,000 GW. This represents a 25-fold increase in solar PV capacity in just over 10 years.

Solar power is now the fastest growing energy source in the world. New solar PV capacity expanded 23% in 2021, reaching a record 157 GW added. The growth was attributed to rising energy prices, climate change policies, and the declining costs of solar panels.

Many projections expect the rapid growth to continue. The International Energy Agency (IEA) forecasts global solar PV capacity to more than quadruple between 2021 and 2030 under its stated policies scenario. BloombergNEF predicts solar PV installations to reach 1,945 GW by 2030. If realized, this would mean solar PV generates over 10% of the world’s electricity by the end of the decade.

Much of the growth is expected to come from large-scale utility solar projects as well as distributed rooftop solar on homes, businesses and commercial buildings. With solar energy costs becoming increasingly competitive with conventional power, adoption is accelerating across the residential, commercial and utility sectors.

Policies and Incentives

To accelerate the growth of solar power, governments around the world have implemented policies and incentives aimed at encouraging renewable energy production and use. Two key ways governments are promoting solar energy are through renewable energy targets and financial incentives.

Many countries have adopted renewable energy targets – goals for how much of their energy should come from renewable sources like solar by a certain date. These targets help drive investment in solar by setting an expectation for growth. For example, the European Union has set a target for 32% of all energy to come from renewables by 2030. The United States doesn’t currently have a nationwide renewable target, but many individual states have adopted aggressive renewable portfolio standards.

Governments also use financial incentives to make solar power more affordable. Common solar incentives include tax credits, rebates, feed-in tariffs, renewable energy certificates, and net metering programs. The federal solar tax credit in the U.S. allows homeowners to deduct 26% of solar installation costs from their taxes. Solar rebates provide upfront discounts on installation. Feed-in tariffs require utility companies to pay solar panel owners for excess power they feed back into the grid. These incentives all aim to reduce the upfront costs of going solar.

Future Outlook

The future looks bright for solar energy. With improving efficiency and storage capabilities, along with declining costs, solar is projected to become a major energy source worldwide.

Researchers continue to make advances in solar cell efficiency and energy storage technology. New materials and manufacturing techniques have steadily increased solar cell efficiency over the years, bringing down costs. Energy storage innovations like advanced batteries and pumped hydro storage enable solar power to be available 24/7.

The cost of solar power systems has dropped dramatically in the past decade, making it competitive with fossil fuels in many areas. Solar is now the cheapest form of electricity in history. As costs continue to fall, adoption of solar will accelerate around the world.

Most energy outlooks forecast solar becoming one of the main pillars of the global energy supply. The International Energy Agency predicts solar PV will reach over 25% of global electricity generation by 2050. With supportive policies and technological improvements, solar energy is poised to help lead the transition to renewable energy worldwide.