What is Solar Power? How Does It Work? Definition, Pros & Cons

Solar power is a form of renewable energy derived from the sun’s radiation. It is used for either generating electricity or heating products.

The sun’s energy is captured from sunlight that falls on a surface. This sun’s radiation is then used to generate solar power using photovoltaic (PV) cells or used for heating through solar thermal systems. Urban professionals like you can utilise solar energy to power up their homes and offices in an eco-friendly manner.

Why the need for solar power?

Over the past few decades, the earth has increasingly faced the dual challenges of climate change and global warming. According to the National Oceanic and Atmospheric Administration, in 2023 the average global temperature was 2.12 degrees F (1.18 degrees C) hotter than the 20th-century average. This is higher than any other year since records began in 1850.

This has increased the need for energy security and created an urgency for finding environmentally sustainable solutions towards a clean energy economy.

The adoption of renewable energy sources is a major lever in this direction.

Solar power provides a reliable and eco-friendly way of generating electricity and meeting the earth’s diverse energy needs. Its major advantage is that it is decentralized, that is it can be accessed anywhere the sun’s radiation reaches. This has allowed for its widespread adoption across residential, commercial, and industrial sectors.

Also, advancements in solar technology and its improving cost economics have made solar energy increasingly competitive with traditional fossil fuels.

See there is a huge potential to generate clean energy using solar power. As per a post by Elon Musk on X, “The amount of solar energy received by Earth could power a civilization over 100 times larger than ours!”. As per a theoretical calculation, the current world demand for power can be met by covering just 1.2% of the Sahara Desert with solar panels. This clearly shows the huge potential that

Solar energy is majorly enabling Governments, businesses, and communities to prioritize sustainability and reduce their carbon footprint, which is major under the United Nations Sustainable Development Goals (SDGs).

If you would like to learn about solar power in just a minute, you should watch this video.

How Does Solar Power Work?

Solar power converts sunlight into electricity through photovoltaic cells or heat through solar thermal systems. The generated electricity is then either used, stored for later use, or fed into the grid.

We will talk about each of these in detail:

1. PV Systems

Solar photovoltaic systems convert sunlight directly into electricity through the photovoltaic effect. It is done as follows.

Solar PV panels consist of individual solar cells made of semiconductor materials, usually silicon. When sunlight strikes the surface of these cells, photons (particles of light) are absorbed by the semiconductor material.

The absorbed photons transfer their energy to electrons in the semiconductor material. This causes them to become excited and break free from their atomic bonds. This creates electron-hole pairs, where electrons can freely move within the material.

Source: Tssenthi, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

The semiconductor material in the solar cell is already treated to create an electric field. This is achieved by introducing different types of dopants (impurities) into the material, creating regions with excess positive and negative charges.

Solar cells have a bridge between the positive and the negative charge regions. Due to the presence of the electric field, the free electrons are pushed towards the front surface of the solar cell through the bridge, while the positively charged holes are pushed towards the back surface.

As the electrons move towards the front surface of the solar cell, they are collected by metal contacts on the surface, creating an electrical current. This flow of electrons constitutes solar electricity.

You can see the following video to get an idea of how solar panels work to generate electricity.

Source: Good Energy Channel, YouTube

The electrical energy generated by individual solar cells is typically direct current (DC). The DC electricity produced by each solar cell is combined through wiring within the solar panel to generate a higher voltage and current.

To harness solar energy in most applications, such as powering household appliances or feeding into the electrical grid, the DC, however, needs to be converted into alternating current (AC) using an inverter.

For this, the DC electricity generated by the solar panels is passed through an inverter.

The converted AC electricity can then be used to power electrical devices or fed into the grid for use by others. It can also be stored in batteries for later use, particularly in case of off-grid or hybrid systems.

2. Grid Connection and Energy Storage

Once the electricity is generated, it must either be used, stored, or fed into the electricity grid. This makes grid connection and energy storage an important part of solar power systems.

Solar power systems are generally connected to the electrical grid to facilitate the distribution and utilization of generated electricity.

As mentioned before, inverters are first used to convert the DC electricity generated by solar panels into AC electricity compatible with the grid and household appliances. Grid-tied inverters also synchronize the phase and frequency of solar-generated AC electricity with the grid.

When electricity is being supplied to or drawn from the power grid, net metering is used. This enables solar system owners to receive credit for excess electricity exported to the grid.

Also, during periods of low solar generation, such as at night, the grid provides electricity, and the solar system owner draws from their credited surplus.

Grid operators employ advanced control and monitoring systems to manage fluctuations in solar generation and maintain grid stability. Strategies such as demand response and smart grid technologies optimize grid operations and accommodate variable solar output.

Solar power generators can also use Energy Storage Systems (ESS), such as battery storage to store solar energy for later use. This electricity can be used when the usable energy generated is low such as on rainy days.

Lithium-ion batteries are commonly used in residential and commercial solar systems due to their high energy density, efficiency, and fast response times.

Other energy storage technologies, such as flow batteries, pumped hydroelectric storage, and thermal energy storage are used depending on the application requirements.

Hybrid solar systems are also used. These systems combine solar photovoltaic cells with energy storage and often include backup generators or grid connections to ensure an uninterrupted power supply. These systems provide the best of both worlds by combining self-consumption with storage and grid connectivity.

Energy storage systems can participate in grid services and ancillary markets, providing valuable services such as frequency regulation, peak shaving, and voltage support.

Solar technology has also seen significant advancement leading to a decline in costs. This has led to their increased adoption and an acceleration towards the transition to a sustainable and renewable energy future.

3. Solar Thermal Systems

Solar energy is also used for heating. This works by harnessing the heat from sunlight to generate hot water or steam for various purposes, including heating a particular area, water heating, and electricity generation.

Solar thermal systems use collectors to capture concentrated sunlight and convert it into heat. There are different types of collectors such as flat-plate collectors and concentrated solar power plants containing parabolic troughs or dishes.

The collector used is usually made of a dark-coloured material or coated with a selective coating to absorb sunlight efficiently. When sunlight strikes the collector’s surface, it heats up, transferring thermal energy to a heat-transfer fluid (usually water or a heat-transfer fluid like antifreeze) circulating through the collector’s pipes or tubes.

The heated fluid carries the thermal energy away from the collector to a heat exchanger or storage tank. In some systems, the heat transfer fluid passes directly through the storage tank, transferring its heat to the water inside.

Solar thermal systems often include a storage tank to store the heated water or fluid for later use, ensuring a continuous supply of hot water or steam, even when sunlight is not available (e.g., during cloudy days or at night). The storage tank is also often insulated to minimize heat loss.

The stored hot water or steam can be used directly for various purposes, such as space heating, domestic hot water supply, or industrial processes. In some cases, hot water or steam generates electricity by driving a turbine connected to a generator.

Solar thermal systems also sometimes contain control systems to optimize their performance and ensure efficient operations. These include sensors, valves, pumps, and controllers to regulate the flow of heat transfer fluid, monitor temperatures, and adjust system parameters as needed.

Pros of Solar Power

1. Sustainable and Environment-friendly

One of the biggest advantages of using solar power is that it is sustainable and environmentally friendly. It helps mitigate climate change and preserve natural ecosystems, thereby creating a sustainable future.

Using solar energy can help reduce dependence on fossil fuels such as coal and natural gas leading to a reduction in greenhouse gas emissions and air pollution.

It also minimizes water usage and land disturbance associated with conventional energy sources. This creates a cleaner and healthier environment for future generations.

2. Renewable sources with abundant supply

Solar energy offers the most abundant energy resource. As long as the sun continues to shine, solar panels can generate electricity, providing a reliable and long-term energy source. This abundance ensures energy security and reduces dependence on finite and polluting fossil fuels.

3. Energy independence

Solar power allows for energy independence by decentralizing energy production as solar panels can be installed by individuals, communities, or businesses to generate electricity.

This can reduce reliance on centralized power grids and burning environmentally harmful fuels to generate electricity. This also allows consumers to hedge against rising energy costs and enhance resilience against disruptions creating increased autonomy and security in energy supply.

4. Opportunity for revenue generation

It provides an opportunity for revenue generation through various channels. Individuals and businesses can sell excess electricity back to the grid through net metering programs, earning credits, or monetary compensation.

This can also help solar power producers generate revenue by selling electricity to utilities or through power purchase agreements.

Additionally, investing in solar projects can also give returns through government incentives, tax credits, and renewable energy certificates.

Cons of Solar Power

1. Weather dependent and chances of disruption

One major drawback of solar power is its weather dependency as solar panels require sunlight to generate electricity. Cloudy days, nighttime, and seasonal variations can lead to fluctuations in energy production disrupting the power supply.

Additionally, extreme weather events like storms or heavy snowfall can damage solar infrastructure leading to temporary outages. These weather-related challenges highlight the need for supplementary energy storage and backup systems.

2. Initial costs and technology adoption

Another con of solar power is the high initial costs associated with its installation and technology adoption. While solar panel prices have decreased significantly in recent years, upfront expenses for purchasing and installing solar systems can be substantial. With technological advancements and Government support, these initial costs can be somewhat mitigated.

What is, however, important is that a complete life cycle analysis be done. It is important to understand the complete picture such as long-term savings on energy bills and carbon mitigation that can offset these initial investments.

3. Need for large land areas

A limitation of solar power is its requirement for large land areas to accommodate utility-scale solar installations. Solar farms and arrays need a large space, which can compete with agriculture or natural habitats.

Moreover, the land-intensive nature of solar projects may become a challenge in densely populated areas or regions with limited available land. A possible solution to this can be the installation of solar rooftop solutions.

Summing up

Solar power uses the sun’s energy to generate electricity or heat. It is a renewable form of energy with an abundant supply that can offer a sustainable and environment-friendly form of clean energy.

Solar power has numerous benefits such as reduced greenhouse gas emissions, and energy independence. Urban professionals like you can harness solar energy to power their homes and offices.

It also has certain disadvantages such as it is weather-dependent and having high initial costs for installation. Also, solar installations require significant land areas, potentially competing with agriculture or natural habitats.

However, despite these drawbacks and with ongoing advancements in technology and a focus on sustainable development, solar is a great option for transitioning to cleaner, more sustainable energy sources.

What is solar power?: (Frequently Asked Questions)

1. What is the technology cost for installing solar panels?

The technology cost for installing solar panels varies depending on several factors, including the type and size of the solar system, location, installation complexity, and quality of components.

With advancements in solar technologies, the prices of solar panels have declined considerably over the years. As per Solar.com, since 2010 price of residential solar panels has fallen by 50%.

Today, premium monocrystalline solar panels cost on an average between $1 and $1.50 per watt and the less efficient polycrystalline panels typically cost about $0.75 per watt.

The cost of solar panels makes up less than 20% of the total cost of solar installation. Other expenses include inverters, mounting hardware, wiring, permits, labour, and associated equipment.

Government incentives, such as tax credits and rebates, can help offset some of these costs. Additionally, financing options like solar loans or leases allow homeowners to spread out the upfront cost over time, further reducing the financial burden of solar panel installation.

It is important to consider the life cycle cost of solar power along with its environmental benefits to get the complete picture.

2. What is the intensity of solar radiation required for generating electricity?

The intensity of solar radiation required for generating electricity varies depending on the type of solar technology used and the efficiency of the solar panels.

When sunlight falls on a panel, anywhere between 10-20% of the energy is converted to electricity. Generally, the maximum irradiance of solar power measured on a clear day is about 1000 W/m2. This intensity, often referred to as “full sun” or “peak sun,” represents the amount of sunlight received under clear, direct sunlight conditions at solar noon.

Solar panels can still produce electricity at lower intensities, although with reduced efficiency. This could be due to several factors such as the presence of water vapours, clouds, dust, etc.

Solar radiation levels could also fluctuate throughout the day and are influenced by factors such as weather conditions, time of year, and geographical location. In regions with ample sunlight, such as deserts or tropical areas, solar radiation levels tend to be higher, resulting in increased electricity generation potential.

To maximize energy output, solar panel installations are typically positioned to receive optimal sunlight exposure throughout the day, adjusting tilt and orientation as needed to capture the maximum amount of solar radiation.

3. Is solar the best form of renewable energy?

This depends on various factors such as geographical location, energy needs, and local resources. Solar power has significant benefits, including abundant availability, scalability, and minimal environmental impact.

It is particularly well-suited for decentralized energy production and can be integrated into a wide range of applications.

Other renewable energy sources like wind, hydroelectric, and geothermal power also have distinct advantages. Wind power, for instance, can be more cost-effective in regions with consistent wind patterns. Hydroelectric power provides reliable baseload electricity in areas with suitable water resources.

The best form of renewable energy is dependent on your requirements and involves a combination of factors such as reliability and cost-effectiveness. The best-suited solution generally would vary depending on local conditions and priorities.

4. What is net metering of energy?

Net metering is a billing arrangement that allows owners of solar panels or other renewable energy systems to receive credit for the electricity they generate and send back to the grid.

When a solar system produces more electricity than is needed on-site, the excess electricity is fed back into the grid. It works by installing a special utility meter that can measure both the electricity consumed from the grid and the surplus electricity exported to the grid.

The meter tracks the “net” difference between the amount of electricity consumed and the amount generated, hence the term “net metering.”

At the end of the billing period, the customer is billed for the “net” amount of electricity used from the grid.

If the solar system generates more electricity than the customer uses during the billing period, they receive a credit on their electricity bill.

This credit can then be used to offset future electricity consumption, typically rolling over month-to-month or year-to-year.

You as a Reclimatize Warrior can use net metering to offset your electricity consumption and even generate some additional cash.

Net metering policies vary by location and utility company. Net metering provides an incentive for consumers to invest in solar energy systems by allowing them to offset their electricity costs with the excess energy they produce. It is an effective way to encourage the adoption of renewable solar power.