Brief Overview Of Solar Technology

Published Date: 02 Nov 2017

MIET2032_1310

SOLAR ENERGY

Renewable Energy Systems: Assessment 1

Salman Jamal 3341539

Sheng Wang 3324922

Introduction

By definition, solar energy is an electromagnetic energy that is radiated by the sun and is said to be a few thousand times greater than all the energy used by the whole population. Solar energy is harnessed by capturing the sun’s heat through solar heaters or light photovoltaic cells (business dictionary). As of all other energies, solar energy is then converted into mechanical or electrical energy. To be precise the photons (solar packs of energy) from the sun rays are passed through a device which can convert it into actual work done. The history of solar energy dates back until the 18th century. In 1838, Edmund Becquerel presented his research on the conversion of sun rays into actual energy. His research spoke of materials being more conductive than others when exposed to sunlight (also known as photoelectric effect). Unfortunately, his research wasn’t taken seriously but this was a milestone in the discovery of the uses of solar energy. In the early 19th century Albert Einstein published his research regarding photoelectric effect which won him his noble prize. This created a sudden expansion in the solar field. The 1950’s witnessed the invention of the first commercial solar panel and even though the solar panel was highly inefficient and ridiculously expensive, it set the platform for the highly efficient and high-end panels in the years to come.

Brief Overview of Solar Technology

Solar energy consists of light and heat emitted by the sun, in the form of electromagnetic radiation. Nowadays we have devices which can convert the electromagnetic radiation into useful forms of energy such as electricity and heating which are called photovoltaic systems. There are 5 main types of photovoltaic systems – simple PV system (involves no storage), PV system with a storage cell (involves storage), PV systems with backup generators (generators which are powered with different source of energy like petrol, hydropower, wind power etc...), small grid-connected PV systems (excess power stored in the grid for times when the system cannot meet the sufficient needs) and large grid-connected PV systems (used for large scale requirements) These devices which convert sun rays into electricity use a process called photoelectric effect. Photoelectric effect is a process in which sun rays are absorbed by a surface of metal and in return electrons will start to move from one side of the metal to the other. The movement of these electrons produces electricity. The amount of electricity produced is in direct proportion to the smoothness of the metal surface and the ease of the emission of electrons from the metal. Silicon is the commonly used metal in the solar field due to its ultraviolet (UV) stability and moisture resistance, electrical insulating, low ionic impurities and its durability at high temperature. The most popular equipment to capture sun light is a solar cell which works on the same principle of photoelectric effect which is also made of semiconductors such as silicon and germanium. These solar cells are used in many devices such as solar panels, solar calculators, solar heaters, solar cookers and many more.

Advantages and Disadvantages of Solar Energy

Renewable energy is an energy which is derived from nature and is completely replenish-able. Solar energy is one of the few renewable energies available. Solar energy is completely dependent on the sun so as long as there is plenty of sunshine there would be an abundance of solar power, unlike coal which require a long period for it to be available. However, the downside of solar energy is that it produces less energy than coal due to lack of technology and equipment to harness the power in the solar field.

One of the most important features of any energy is its ability to produce less harmful by products. Coal is the world’s most used source of energy which produces the most air pollutants compared to other sources of energy. Coals by products include sulphur-dioxide, carbon-dioxide and nitrogen-oxide which are the major constituents of smog. On the other hand solar energy does not produce any air pollutants as it does not involve any combustion of fuel. But although solar energy does not give out any air pollutants, it gives out toxic waste in the form of cariogenic. However, solar energy is the only energy that can be harvested in space which can provide a way to obtain energy.

Costing is one of the few disadvantages of solar energy. The cost of solar energy generated per hour is ridiculously expensive; 0.022$KWH compared to that of other sources such as nuclear power - 0.04$KWH, hydropower - 0.03$KWH, coal – 0.04$KWH, natural gas – 0.10$KWH, petroleum – 0.10$KWH and wind power – 0.08$KWH. Another disadvantage of solar power is that it is impossible to obtain it when the sun is down unlike the nuclear energy which can be obtained at any time of the day. Solar energy generation can also be affected by weather conditions such as cloudy weather which could reduce the absorption up to 50%. Hailstorms and thunderstorms could affect the surface of the panel used to absorb sun’s rays resulting in poor absorption rate. Weather conditions can also drastically affect the power output of the solar cell. For example the open-circuit voltage decreases with the increase in temperature (Note: the short circuit voltage slightly increases with increase in temperature) However, there are also some weather conditions that could boost the absorption effect like when a group of cumulus clouds gather up together reflecting light from the sun on the solar panel. Solar panels are bulky, hard to transport and have a very low efficiency of 22%. To increase the efficiency, the solar devices will require more space to occupy or will need to be installed with mirrors to direct the light towards the panels which only contributes to the unpopularity of solar energy. On the upside, these panels have a very long span of 20 years and do not require any maintenance throughout their life time. The sun’s rays are found in every region of the world which provides energy to rural regions unlike other resources such as coal which needs to be dug in specific regions; wind energy which can be harvested only in specific seasons and hydro power is not practical on flat terrains. Solar energy prices can never change due to the fact that sun is an infinite source of energy however coal prices keep changing depending on the availability of coal at different regions. The main issue with solar power is that solar batteries are ridiculously expensive and have a very low storage capacity. Despite that it provides a safer method of obtaining energy unlike nuclear power plants which involves using high radioactive elements which comes at a high risk.

How a compromise can be achieved

Less dependency on coal could increase the solar energy usage. The dependency of coal can be reduced by using the following methods. The first method is improving solar energy storage by providing enough resources for research in solar cells which can help fix the unavailability of energy at night or stormy seasons and by using different semiconductors which can result in reduction of toxic waste due to the silicon based solar panels. The next method is to manufacture much higher efficiency solar panels to produce more electricity using less sunlight. By also providing a reasonably priced technology for low income families it could increase solar technology demand. An alternate way of avoiding unstable weather conditions is by installing solar panels in satellites which also powers up equipment in space that could help us discover a larger portion of space. These methods would reduce the usage of coal which in turn reduces the greenhouse gas emissions which is inversely proportional to the absorption of the solar panels, making them produce more power. The other benefits of these methods include cleaner environment and conserving the flora and the fauna.

Conclusion

In a nutshell, solar energy is one of the most widely available renewable energies. It not only is available nationwide, it can also be harvested in space, making it possible for satellites to be powered for an even longer period of time. Furthermore, solar energy produces less harmful by products, and has a much safer method of obtaining energy as it does not possess the possibility of being radioactive. Despite that, there are some drawbacks to solar energy. For starters, it is ridiculously expensive to install and maintain the solar panels. The solar panels are also bulky and are very hard to transport. With bad weather conditions, solar energy can almost be rendered useless as it reduces the absorption rate by half. After doing a considerable amount of research, we think that the only way that the use of solar energy can be increased is that if a research is conducted on the availability of solar energy at night and if a cheaper option is provided for the installation and maintenance of the solar panels. Solar energy could also be a more popular option in countries where the sun always shines like for example in the Middle Eastern countries. Reason being that even in the winter season there would be an abundance of solar energy.