Solar Energy

The total solar energy received by Earth is much more than the world's total anticipated and current energy requirements, but not even 10% of it is used for fulfilling the energy requirements. If this solar energy is harnessed in the right way, it has the potential to satisfy all future energy needs. The biggest advantage is that solar energy is a renewable energy source, and therefore if once the right techniques to harness most of it are developed, there will be no need to look for alternate sources of energy in the future. Today, the use of solar energy became so much common, yet it is only used to generate only 3.5% of the world's total electricity requirements. The use of solar energy is increasing, and it is becoming a popular choice for generating electricity; still, there are many areas to improve.

Introduction to Solar Energy

The form of energy harnessed from heat and radiant light from the sun using a wide range of technologies and techniques such as Solar architecture, Solar thermal energy, which includes solar water heating, solar power for generating electricity, etc., is known as Solar Energy. Solar energy is an important and the most popular source of renewable energy. Solar energy has become the most attractive and most popular renewable energy choice because of its non-polluting character and inexhaustible supply. The other major reason that the world is rapidly shifting towards solar energy is that current energy sources are non-renewable such as petroleum, fossil fuel, coal, and natural gas, and they are expected to last only till the end of the 21st century.

Solar Energy has so much potential, and it is the most popular current renewable energy choice, yet there is a lot of scope for improvement. In 2020, solar energy only contributed 3.5% of the world's total electricity requirement, which was 3% in 2019. So, there is progress in contribution from solar energy in total electricity requirements, but it is very slow progress, and the figure is very small compared to the potential of solar energy to fulfill our total energy requirements. Data released by Carbon Tracker Initiative in 2021 stated that the total land area needed to generate and fulfill the world's all energy requirements from solar energy is 450,000 Km² (which covers only 0.3% of total Earth's land area), and it is almost equal to the total surface area of Morocco, Sweden, or California. That's why the large magnitude of solar energy available currently makes it the most appealing renewable energy source for electricity generation.

Advantages of solar energy

There are many reasons why solar energy is the most attractive and appealing source of energy for generating electricity. In contrast to any other renewable and non-renewable sources that offer only a certain number of benefits, solar energy has multiple advantages, making it the first alternate choice to non-renewable energy sources. Here are several major advantages of solar energy, which makes it the most popular and most appealing alternate source of energy for electricity generation:

Unlike non-renewable energy sources, solar energy does not cause any kind of pollution, and no greenhouse gas is emitted after installation and during the generation of solar energy. Thus, generation and use of it do not possess any threat to the environment.
Virtually, solar panels do not require any kind of maintenance as they last for more than 30 years.
It is very easy to install solar panels, and they can be installed anywhere; in a building roof, in a field, or anywhere else.
No kind of trenching is needed for the generation of electricity from solar panels since Solars can be placed at the place or close to the place of installation of solar panels.
The efficiency of the solar panels is increasing with the changing technology, and thus, a small size solar panel that is producing less amount of solar energy today will be able to produce a higher amount of energy in the future.
Many governments are offering many kinds of benefits such as tax incentives, rebate programs, and federal grants for the installation of solar panels.
Energy and electricity produced through solar energy are much safer than traditional electric current production.
Batteries can be used with solar panels to store extra solar energy generated by them for future uses.
Electricity produced using solar energy can perform all traditional electricity-based tasks such as providing power to cars, heating water, and even powering homes and buildings.
One can even be grid-free if they are able to generate solar power, which is enough for their home and offices.
Solar panels also generate employment in manufacturing, installation, marketing, and various other departments.
Solar panels or solar power is actually a good source of return of investment as once invested on the installment of solar panels, no need for electricity bills in the future.
Solar power reduces the need for Fossil fuels and foreign oils, which boosts the economy and helps in making the environment pollution-free.

Solar Power: Disadvantages

Solar power also has several disadvantages, including installation costs, the requirement of a large area, and more. These disadvantages of solar energy generation and production are the major reason why there is not any rapid growth in the contribution of solar energy out of total energy consumption in the world. Many of these disadvantages are minor factors, but some of them are serious concerns that can only be solved with the government's help and improvements in the current solar energy generation technology. Following are some major disadvantages of solar power, which include limitations in production and distribution:

Cars that run on solar power have less efficiency as compared to traditional cars, which run on petrol, diesel, or CNG mainly. Solar power-dependent cars have less powerful engines and run at less speed than traditional cars.
The total generation of solar power in a day is totally dependent upon the weather of the day, and one cannot do anything about it. It is possible that cloudy days would not generate as much solar energy as sunny day produces, or no solar energy would be produced on cloudy days.
Electricity or power generated by solar energy is in DC (Direct Current) power form, and devices that run directly on DC power sources cost more than those that run on AC power sources.
No solar energy is available at night time, and therefore, limited time is available to capture the maximum amount of solar energy. And, to capture the maximum amount of solar energy in a limited time, one needs large size batteries and power banks.
The initial cost for the generation and production of solar power is very high because materials used in solar power production are very expensive. Other than this, installation charges are also very high, and the return on investment on solar panels is very long compared to the initial investment made (However, the cost of materials and installation for solar panels is reducing with improvements in the technology, and thus it is becoming cost feasible with time).
As already said, weather affects a lot in the production of solar energy, and that's why the winter season will have the least amount of solar energy production, which will affect energy requirement cycles and sources. Either one has to switch alternate power sources in winter, or they will need a large battery or power storage banks to capture maximum solar energy at once.
There is a lack of material used in the production of solar panels, which is why mass production of solar panels is not possible currently. This non-availability of mass production is set back for lowering their costs and making them affordable for every household.
The production efficiency of solar panels is dependent on the geographical location of where solar panels have been installed, and that's why the production and efficiency of solar panels vary according to the region.
Installation of solar panels needs lots of space, and for their industrial use, one must have a very large area to install them in high numbers.

Most of the above-listed disadvantages of solar energy are only because of the lack of improvised technology and government help for local people. Therefore, improvements in technology and subsidiary help from the government can solve most of these problems and encourage people to buy more solar panels.

Solar Energy: Types of solar energy generation technologies

Technologies used in the generation of solar energy is broadly divided into the following two categories:

Active solar energy generation technology: These are the technologies directly involved in the generation and harnessing of solar energy, such as solar water heating, concentrated solar power cells, photovoltaic systems, etc.
Passive solar energy generation technology: These are the technologies that are indirectly involved in the generation and harnessing of solar energy, such as selecting build materials that support thermal energy generation or are favorable to light-dispersing & thermal mass properties, designing space in the building so that building will naturally collect air & sunlight, orienting a building towards the sun, etc.

The category of technology used in harnessing solar energy depends upon the following three factors:

How the technology captures solar energy
How the technology distributes solar energy
How the technology converts solar energy into solar power

Solar Energy: Application

Solar energy has multiple applications in the everyday work of many households as it can be used to produce many forms of energy. Solar Energy is a cleaner and cheaper source of energy, and that's why it is used in many fields, including agriculture and development work. Following are the most common applications and uses of solar energy:

1) Production of thermal energy:

Solar energy is used to generate thermal energy, further used for many applications such as process heat generation, cooling generation, space cooling, space heating, water heating, etc. The solar hot water system is used for heating the water with the use of sunlight which includes the following most common types of solar water heaters:

Evacuated tube heaters (They cover 44% of all types of solar water heaters)
Glazed flat-plate collectors (cover 34% of all types of solar water heaters)
Unglazed plastic collectors (cover 20% from all types of solar water heaters)

Heating, ventilation, and air applications account for 30% of total thermal energy generated using solar energy and nearly 50% of the energy used in buildings. Applications such as a solar chimney, solar concentrator optics, etc., are included in the heating, ventilation, and air application category.

The use of solar heating energy or thermal energy is divided according to following two concepts according to the active elements used in the application:

(i) Passive solar concepts

(ii) Active solar concepts

Other than this, solar heating energy is used for the following industrial and household appliances:

Molten salt technology
Solar cooker
Processed heat
Water treatment

2) Electricity generation:

The electricity produced using solar energy either directly using Photovoltaic cells (PV) or by the indirect use of concentrated solar power is called Solar Power.

Photovoltaic cells

Photovoltaic cells convert directly falling sunlight into electricity, and these photovoltaic cells consist of semiconductor material that exhibits photovoltaic properties. The photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry, is used commercially to generate electricity and as photosensors in many devices. In the photovoltaic systems, multiple solar modules are employed, which are used to generate electricity, and each of them comprises a number of solar cells. This system has been in use for very long in many specialized applications, and they give some hope that in the future, photovoltaic technology will be able to produce an ample amount of sustainable energy from sunlight.

Concentrated solar power

Concentrated Solar Power or CSP is a system that uses a tracking system and mirrors or lenses to focus on a wider area of sunlight into a smaller beam so that concentrated heat can be generated. After that, generated concentrated heat is used as a source of heat in the conventional power plants to produce electricity. In today's time, multiple techniques have been developed that are used for tracking and focusing on sunlight. The most developed among them are the solar tower, the striling dish, the concentrating linear Fresnel reflector, and the parabolic trough.

3) Urban planning and architecture:

Solar energy has vastly affected the urban planning and architecture of building so that they can be used as passive sources of solar energy collectors. Chinese and Greeks were the first to employ advanced solar urban planning and architecture methods by orienting their building towards the south to capture the maximum amount of sunlight and warmth. Following are some common features of passive solar urban planning methods and solar architecture related to the orientation of buildings:

Thermal mass
Overhangs (Which are used for selective shading of buildings)
Compact proportion (A low surface area to volume ratio)
Orientation relative to the sun

This passive solar architecture and urban planning can produce well-lit spaces when these features are tailored to the local area's environment and climate.

4) Agriculture and Horticulture:

Nowadays, solar energy is also widely used in agriculture and horticulture technologies to provide maximum productivity at a cheaper cost. The agriculture and horticulture sector optimize the productivity of plants by capturing solar energy in an optimized manner by using multiple techniques such as mixing plant varieties can improve crop yield, staggered heights between rows, the tailored row orientation, and timed planting cycles. Greenhouse technology is used to convert solar energy into heat, and after that, generated heat has been used as a source of power, enabling the growth of especially crops & plants whose existence is not naturally possible in that local climate and year-round production of multiple desired crops & plants.

5) Transport:

Nowadays, many specialized transportations and other vehicles use solar energy as their power and fuel source. Many vehicles are equipped with solar panels for auxiliary power for many purposes, such as air conditioning, which reduces the traditional fuel consumption of vehicles.

Solar Energy is also used in many other applications and sectors, which falls under the following category: