What Is The Most Common Type Of Solar Energy?

Solar energy is the radiant light and heat from the sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, and concentrated solar power. As concerns over climate change and the environmental impacts of fossil fuels grow, solar energy has emerged as one of the most promising sources of renewable energy with the potential to meet a significant portion of the world’s energy needs.

Transitioning to renewable energy sources is crucial to reducing global greenhouse gas emissions and averting the worst impacts of climate change. Solar energy offers a clean, abundant, and renewable alternative to burning fossil fuels. Understanding the different methods of harnessing solar power is key to realizing its immense potential.

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Photovoltaic Solar

Photovoltaic (PV) solar panels are the most common type of solar energy system found today. PV panels, also known as solar modules, convert sunlight directly into electricity through the photovoltaic effect. The process starts when photons from sunlight strike the solar cell material, usually silicon, and knock electrons loose from their atoms. The flow of these electrons generates an electric current that can be captured and used.

PV panels are made up of many individual solar cells wired together. The panels can vary in size from small rooftop units to ground-mounted arrays covering acres. Their modular nature provides flexibility in system design and scalability. Panels produce direct current (DC) power which then gets converted to usable alternating current (AC) through an inverter for residential and commercial applications.

Some key advantages of PV solar are its simple and scalable design with no moving parts, low maintenance needs, declining costs, and ability to work in diffuse light. PV systems can be installed quickly in most environments. The main limitations are intermittency, energy storage needs, space requirements, and cost compared to grid power in some regions.

Solar Thermal

Solar thermal systems, also known as solar heat or solar hot water, use the sun’s energy to heat water or other liquids. These systems rely on solar collectors, often mounted on rooftops, that contain tubes or panels through which a heat transfer fluid is circulated. The fluid absorbs heat from the sun and carries it to a storage tank. The heated liquid can then be used for purposes like domestic hot water, space heating, or even to generate electricity.

The main components of solar thermal systems are the solar collectors, storage tanks, pumps, heat exchangers, and piping. There are two primary types of solar collectors: flat plate collectors, which are boxes covered in glass with dark absorber plates inside, and evacuated tube collectors, which contain rows of parallel glass tubes.

Some key advantages of solar thermal technology are:

Simple, proven technology that has been around for decades

Can provide 50-80% of a building’s hot water needs
Works well even in cooler, cloudier climates
Can be used for heating pools as well as buildings

Greater efficiency than solar PV in converting sunlight to heat

Some potential downsides include:

Doesn’t work well for electricity production compared to solar PV

Requires adequate roof space and solar access
Upfront costs can be high despite long term savings
Backup heating system may still be needed

Risk of freezing in very cold climates

Overall, solar thermal represents a fairly mature yet underutilized solar technology with the ability to dramatically reduce water heating loads and fossil fuel consumption. With the right climate and application, it can be a smart, eco-friendly energy solution.

Concentrated Solar Power

Concentrated solar power (CSP) uses mirrors or lenses to concentrate a large area of sunlight onto a receiver. The concentrated light is converted to heat, which drives a steam turbine connected to an electrical power generator. CSP allows for thermal energy storage, providing power even when the sun isn’t shining.

There are four types of CSP technologies:

Parabolic trough systems use curved, U-shaped reflectors to focus sunlight on a receiver tube running along the mirror’s focal point. This heats up a transfer fluid which is used to produce steam.
Power tower systems use a field of flat, movable mirrors (heliostats) that focus sunlight onto a central receiver on top of a tower. The receiver contains a fluid that is heated to a high temperature.

Parabolic dish systems use a mirrored dish similar to a very large satellite dish. The dish-shaped surface directs and concentrates the sunlight onto a central engine that generates electricity.
Linear Fresnel reflector systems use multiple flat mirrors placed at different angles to concentrate sunlight onto elevated receivers.

The pros of CSP include:

Ability to store thermal energy allows power generation on demand, including at night.
Dispatchable renewable energy complements intermittent sources like solar PV and wind.
Siting flexibility since CSP requires direct sunlight but not large land areas.

The cons of CSP include:

More complex systems with higher capital costs than solar PV.
Large amounts of water needed for cooling and steam turbine operation.

Lower efficiency and energy conversion rates than PV.

Photovoltaic Dominance

Photovoltaic solar panels, often referred to as PV panels, comprise the vast majority of installed solar capacity globally. According to the International Energy Agency, PV accounted for 98% of global solar additions in 2021 and held 95% of total operating solar capacity at the end of that year. In the past decade, PV technology has seen dramatic reductions in costs while simultaneously increasing efficiency, making it the most economical and versatile form of solar power. As of 2021, the levelized cost of utility-scale PV in the best regions dropped below $30 per MWh, undercutting costs for new fossil fuel generation. The modular nature of PV also enables scalable deployments, from residential rooftop systems to massive solar farms. Thanks to these advantages, PV has dominated growth in annual solar installations for over a decade. With solar power rising as a major contributor to future energy demand, PV is positioned to maintain dominance as the leading solar technology worldwide.

Growth Trends

According to industry analysts, the global photovoltaic solar market has experienced exponential growth over the past decade. The installed capacity of PV has increased from 1.4 gigawatts in 2000 to over 600 gigawatts by 2019. This represents a compound annual growth rate of over 42%.

Several key factors have driven the rapid adoption of PV technology. Government incentives and policy support like feed-in tariffs, renewable energy mandates and solar tax credits have helped spur demand. Costs have declined dramatically as manufacturing capacity, economies of scale, efficiency improvements and technology advances have brought down panel prices by over 90% since 2009. Meanwhile, increased awareness of climate change and the urgent need to transition to clean energy has made PV an appealing choice for consumers, businesses and utilities.

Looking ahead, analysts project the PV market will continue its robust expansion. One forecast estimates global solar capacity could reach over 8,500 gigawatts by 2030, with PV representing the lion’s share of additions. Key growth markets are expected to be China, the United States, India and Europe. If projections hold true, solar PV will play a major role in the world’s energy future.

Reasons for Popularity

Photovoltaic solar has become the dominant form of solar energy due to several key factors that have driven down costs and improved efficiency over the last decade. The main reasons behind the popularity and growth of photovoltaic solar include:

Falling Costs – The cost of photovoltaic panels and associated system components has dropped dramatically in the past 10 years. This is largely due to improvements in manufacturing and economies of scale as installation volumes have increased globally. The levelized cost of electricity from residential solar PV systems fell by over 60% between 2010 and 2020.
Improving Efficiency – Advances in solar cell technology and module design have steadily increased the conversion efficiency of photovoltaic panels. The average efficiency has increased from around 12% to over 20% for premium panels over the past 15 years.
Modularity – Photovoltaic systems can be scaled up or down easily. PV panels are interchangeable modules that can be added to over time. This flexibility of system design and expansion has facilitated adoption.

Peak Power Generation – Solar PV generates the most electricity during peak daytime hours when electricity demand is highest in many markets. This alignment of generation and load profiles increases the value of PV electricity.
Environmental Benefits – Solar PV generates clean renewable electricity without any fuel-based emissions. The environmental advantages have made PV an attractive option for policymakers and consumers.

These factors of improved economics, efficiency, flexibility, and sustainability have all contributed to making photovoltaic solar the dominant technology in the growth and adoption of solar energy around the world.

Challenges

While photovoltaic (PV) solar is popular and continues to grow quickly, it faces some challenges that limit more widespread adoption:

High upfront costs – Installing a PV system requires significant initial investments before long-term savings can be realized.

Intermittency – PV only generates electricity when the sun is shining, requiring storage or a supplementary power source.
Land usage – Utility-scale PV farms take up large areas of land which could serve other purposes.
Toxic materials – Some PV panel components use heavy metals and other toxic materials that must be disposed of properly.

Grid integration – As more distributed PV electricity enters the grid, managing and balancing the grid becomes more complex.

While these challenges do not negate the many benefits of PV solar, they help explain why adoption has not been even faster. Ongoing R&D aims to reduce costs further and improve solar efficiency to mitigate some of these limiting factors.

Other Applications

In addition to the major types of solar power, there are some emerging solar technologies that show promise for niche applications:

Solar fuels – Using sunlight to convert water and carbon dioxide into energy-rich fuels like hydrogen.
Floating solar – Installing solar panels on bodies of water instead of land to make use of otherwise unused space.

Solar-powered vehicles – Cars and planes that use solar cells to directly convert sunlight into electricity to power electric motors.
Solar fashion – Clothing and textiles that incorporate flexible solar cells to power small electronics.

While these technologies are still emerging, continued innovation and declining solar costs could enable wider adoption in the future.

Conclusion

In conclusion, solar photovoltaic is by far the most common type of solar energy, accounting for 60% of global solar deployment. Photovoltaic technology works by converting sunlight directly into electricity through use of solar panels. Solar PV systems are used in residential and commercial settings and large-scale solar farms.

Solar PV is expected to continue to see significant growth in the coming years thanks to its affordability and accessibility compared to other solar technologies. Government incentives, technology advances, and economies of scale are also driving increasing adoption of PV systems to scale up renewable energy. While certain challenges remain, solar PV will likely maintain dominance as the leading form of solar energy for years to come.