What comes in your mind when you heard Solar Energy? Firstly know that we all are consuming solar energy directly or indirectly. You are going to learn about every aspect of it in this article.
What’s in it for me?
- History of solar energy
- Two main ways to generate solar power
- The efficiency of Solar Power
- Advantages of Solar Power
- Disadvantages of Solar Power
Solar energy is the energy that we harvest from the sun. In the form of light and warmth to generate electricity or produce heat.
To harvest this energy we use panels and mirrors.
History of solar energy
Sun has been the ultimate source of solar energy for billions of years. And serves a key role in the energy resources we use in our daily activities. If you go back in history to find out where all it starts and who invented solar energy. certainly we can say it is ancient bacteria who discovered solar energy.
Around 4.6 billion years ago the sun was formed. When nebula (Cloud of dust and gas) collapsed due to its own gravity.
If we try to find modern solar technologies birth, then we will know the roots of modern solar technologies are from around 1839. during this period Edmond Becquerel who was a French physicist studied the solar spectrum and he discovered the photovoltaic effect.
(Photovoltaic effect is the process of generation of voltage and electric current in a material. When it is exposed to solar energy (sunlight). On this phenomenon solar panel works that we will see in detail later.)
In the 19th century, French inventor Mouchet had developed the first parabolic trough solar collector. Which was presented to the emperor Napoleon III in Paris and around 1860 he registered solar-powered engine patents. In 1878 he with the help of his assistance Mr. Abel Pifre developed first-ever solar-powered printing press.
In the Universal Exhibition of Paris, Mouchet won the gold medal for exhibiting his solar-powered engine. But the French Government said that solar power is not economical and stop funding.
The commercialization of solar power is started around 1883 when American inventor Charles Fritz invented the first working selenium solar cell. In 1883, Russian scientist Aleksandr Stoletov patented the first true solar cell in1888.
In 1891, Clarence Kemp patented the first commercial solar water heater.
Solar Energy in 20th century
Solar power got its due when Albert Einstein published a paper on the photoelectric effect In 1905. Bell Labs then produce the first modern solar cell in 1954 but the cost of it took was very inefficient.
It took $250 to generate a mere 1 watt of electricity, compared to $2 – $3 per watt from coal plants at that time. In 1958 the Vanguard 1 spacecraft used solar as a backup energy source.
Still solar was not got its due but it is in 1970 when the surge in renewable energy took place in the world because of the adverse effect of fossil fuels on the environment people started looking at solar energy as a potential alternative as a clean source of electricity.
In this period advancement in the field of solar energy bring it to cost from 250$ to 20$. Now in 2020 this cost is as less as 2.57-3.35 US dollars make solar energy the best available energy to use.
In India as per the TERI study cost of solar energy will fall to Rs. 1.9 kilowatt-hour by 2030. Right now it is ranging between Rs 2.50-2.87 per kilowatt-hour in May 2020 and it is 20-30 percent cheaper than thermal power in India and 50 percent lower than coal-fired power.
Source : Economic Times
Two main ways to generate solar power
In this process, photovoltaic solar cells in panels absorb the sunlight and convert it into DC electricity using the photovoltaic effect.
(Inverters convert this Dc current into AC current.)
Photovoltaic solar cells use photons in sunlight and liberate electrons to generate electricity.
The costs of these solar panels have decreased drastically in the last decade and due to that now manufacturing these panels are very affordable and cheap forms of electricity.
Solar panels have a lifespan of 25-30 years it doesn’t mean that it will stop producing electricity but the production rate will be decreased.
There are three main systems under Photovoltaics (PV) solar power generation System.
Grid-connected PV system
This system is consists of PV modules, grid-connected inverter, mounting hardware, electric cable, and safety device.
This is a very common and cost-effective system.in this system, you can use the local utility grid when the PV system is not fulfilling your need and you can also export excess electricity back to the utility company when the PV system supplying more than required electricity.
The rate of this electricity and its measurement is varied by country to county and state to state. The downside of this system is it will automatically shut down if the grid becomes unavailable as you are still connected to it.
Grid-connected PV system with batteries
The complete connection is as same as the Grid-connected PV systemonly battery bank added in this system.
The advantage of this system is you can charge the batteries using this system in the day time and then you that electricity storage whenever needed. This system can use to supply a DC load from the battery bank.
Off-grid PV system
These systems are generally located in remote areas and areas that are not connected to the main power grid. In this system generated electricity is used to charge battery banks and then used to DC load or Ac load via an inverter.
This system provides independence from the power grid as the main power grid is not involved in this. But the downside of this is it can be a limitation when the required power is more as batteries and inverters have their own limitations.
Other important parts involved in PV systems are charge controller (make sure that batteries don’t overcharge) and utility meter (measures the electricity consumption).
Concentrated solar power (CSP)
In this method, thermal collectors use mirrors to absorb and store solar heat and transfer it to the fluid which creates steam to drive the turbines and eventually generate electricity.
There are three main systems under concentrated solar power generation.
Parabolic trough system
This system is consists of parabolic curved, trough-shaped reflectors and receiver pipe running along the curved surface. Solar energy is used to heat oil that is flowing through the pipe and conventional steam generators use this heat to generate electricity.
Solar collectors comprise of multiple parabolic trough-shaped mirrors in parallel rows aligned to the north-south axis.
This configuration enables the single-axis troughs to track the sun completely through the day to ensure that the sun is continuously focused on the receiver pipes so we can utilize maximum energy from the sun.
Power tower system
In this system, the power tower converts the sun’s energy into electricity. In this technology, many large sun-tracking mirrors also called heliostats are used which focuses sunlight on a receiver at the top of a tower.
Fluid in the receiver get heated and used to generate steam this steam further used in a conventional turbine generator to produce electricity.As per US design molten nitrate salt use as heat transfer fluid because of its superior heat transfer and energy storage capabilities.
In European design they use air because of air’s easy handling ability.
Solar dish system
In this system, we use a parabolic dish called reflectors that reflects solar radiation onto a receiver mounted at the focal point.
To collect max energy coming from the sun we mount reflectors on a structured track of the sun along the two-axis
The heat engine (Stirling engine) utilizes the collected heat to generate power. Heat engines mounted on the receiver and they move with the dish structure.
The efficiency of Solar Power
The efficiency of solar power systems depends on the technology we used to convert the solar energy to electrical energy, while this operations there are losses in energy like heat rejection and thermal losses, plus other losses present in conversion system.
The Power tower type of system claims to have an efficiency of 23-35% at an operating temperature between 250-50 degrees Celsius. Whereas the solar disk system claims to have an efficiency of 30% while operating at 550-750 degrees Celsius.
But considering the variations in temperature and weather plus system losses we can say power tower can give efficiency of 7-20% whereas solar disk system can give us an efficiency of 12-25% as annual net solar to electricity efficiency.
Advantages of Solar Power
- Renewable energy.
- Non-polluting energy.
- Sustainable energy.
- Reduces the use of fossil fuels.
- Low maintenance cost.
- It Creates a job while installation of solar plants.
- Uses compact and simple technology.
- Useful in big and small applications.
Disadvantages of Solar Power
- The initial cost of installation is high.
- Weather and time-dependent.
- Requires inverters and batters for the constant supply.
- We need a large area to get more power.
- Concentrated solar technology causes a bright light. It attracts insects, birds, and raptors and gets killed.
We have covered all the important aspects of solar energy and now we can say that the sun is the superior source of energy and we have to utilize it as much as we can and avoid using fossil fuels and protect our environment from harmful effects.
The amount of light and heat energy the sun gives in one hour is enough to fulfill the global energy need of one year. The sun plays a vital role in renewable energies like wind energy and tidal energy also.
Also Read :
Solar energy can be used in number of ways like water heating, space heating, cooking, separating salt from seawater in addition to that generating electricity using solar panels.
Solar energy is definitely a renewable energy as it is sustainable and inexhaustible.
Yes.If you are using solar power system with batteries in it then you can store solar energy in it.
My name is Vivek Rawool. I am extremely motivated to constantly develop my skills and grow professionally. I have completed my BE Mechanical Degree from Mumbai University and currently working with Paramount India as a Sales and Marketing Engineer. I also do Share market trading and investment.