Solar energy system

Abstract

Solar power is a form of renewable energy; a term used to refer to any form of energy generated using any other resources other than fossil fuel and nuclear materials. These sources of energy provide are considered clean and environmentally friendly. The world needs electricity for development, and over the years the demand has grown exceedingly leading to more dependency on the fossil fuels which are relatively cheaper in production. Over the last two-decade, concern has been raised on the effect of pollution on the environment due to carbon emission mainly attributed to the use of fossil fuels. Renewable energy has been seen as the solution and in this case solar energy to balancing the amount of carbon dioxide on the planet atmosphere. This paper seeks to establish the reliability, sustainability, affordability, and safety of the solar power energy.

Introduction

For centuries man has depended on electricity for development since its discovery. As the world became more developed so did the dependency grew. For the longest time, the use of fossil fuel for electricity generation has been the norm with no clue of its adverse effect on the environment. Greenhouse gases emitted to the environment has resulted in increased global warming leading to climate change across the world. The world climate has recorded an increase of 0.8 degrees Celsius according to NASA’s Goddard Institute for Space Studies (2018). Although the difference can be seen as small, it has caused a widespread climate change around the world such as flash floods, melting of ice caps, droughts, tsunamis, and hurricanes. It is this concern that the international community decided to think about renewable energy to try and balance the carbon dioxide in the atmosphere.

According to Armaroli & Balzani (2007), solar energy is renewable energy that is clean and thought as the future of energy source. It does not destroy any other resources for it to be produced but instead uses the sun which is readily available and replenished every day. Solar power requires solar panels to help harness the energy from the sun’s sunlight using photovoltaic technology.

The technology uses photovoltaic cells or otherwise known as solar cells. These cells through a complex mechanism convert light energy into electricity (Knier, 2008). The electricity from the cells needs to be stored if it is not used immediately states Kenisarin & Mahkamov (2007); that is the big challenge of the solar energy. Although new technologies on batteries that can store the energy have emerged, they have not yet been fully incorporated in the system. The other option is the on-grid system for that feeds the electricity from the solar panels directly to the grid a phase that is still in the development stages with only a few countries like Germany been able to do so.

However, the challenges are less significant when the pressing most threatening issue of climate change is considered. Hence it makes solar energy as a form of renewable energy an important topic of discussion. Currently, the world consumes up to 10 terawatts per year with a projection of 30 terawatts by 2050 Razykov et al. (2011) asserts. As such, there is need to supplement this demand using renewable energy like solar and wind. Therefore, this module seeks to answer the following research questions concerning solar energy. Is solar power economically reliable? Can it consistently meet the electricity demand? How sufficient is solar power on a small scale? Would it be sufficient on a large scale? Is solar power becoming more affordable? What will ensure it remains affordable? How safe is the use of solar power? Is solar energy system safe for the environment?

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Literature Review

The use of solar panels became widely used in the 1980s although the technology had been discovered way back in 1839 by the scientist Edmond Becquerel (Razykov et al., 2011). Becquerel was studying the effect of light on electrolytic cells when he noticed that the electrodes produced some form of electricity when exposed to light, and that marked the birth of photovoltaic technology. However, the first use of photovoltaic technology came in 1954 through the development of the first silicon photovoltaic cell by scientist Calvin Fuller, Daryl Chapin and Gerald Pearson (Baker, 2016). However, the total amount of energy from the sun the design could convert was only four percent. This percentage is the efficiency of a photovoltaic cell.

Following technological improvement in the technology, in 1960, the efficiency went up to 14 percent and with came the first building to have solar heating – the Bridgers-Paxton explains Bartlett (2015). However, during the 1980s the use of solar panels become more widespread. They were mounted on satellites to power them and used for small-scale light housing.

There is a considerable, consistent decrease in the cost of solar panels since the 1980s to date. Likewise, technological inventions have made it possible to make more light and thin solar panel with increased efficiency hence more electricity. Currently, the highest practical efficiency is 46 percent with a theoretical efficiency of 63 percent (Kobe University, 2017). The decrease in cost and increase in efficiency has encouraged more people to consider purchasing and installing solar panels in their homes and governments and international bodies to consider the large-scale generation of electricity using solar energy.

The photovoltaic panels are of three types – monocrystalline silicon, polycrystalline silicon, and thin-film. The monocrystalline silicon incorporates high-grade silicon which makes it capable of converting 15-20 percent of the sun rays into electricity states Maehlum (2015). As a result, the panel has the highest efficiency making it require less surface area per unit energy produced. Consequently, they are the most expensive compared to the rest.

The polycrystalline silicon panels are made of much lower grade silicon compared to monocrystalline. They are capable of converting 13-16 percent of the total sunlight to electricity (Maehlum, 2015; Wu, 2004). This makes their efficiency much lower than the monocrystalline and hence require a much larger surface area per unit energy produced.

The other type is the thin-film panel made from an ultra-thin light absorbing materials hence the name. Lee & Ebong (2017) clarifies that their manufacture is simple which makes them cheaper compared to the other two types; however, it compromises on the efficiency of the cells. As such, the panel only converts 7-13 percent of the total incoming sunlight to electricity making it the least efficient of the three; therefore, it requires more surface area to match the electricity produced by either of the other panels.

Findings and Discussions

Reliability of Solar Energy System

Reliability of solar power is not just a question of generating electricity consistently. It involves other factors such as economic, environmental and physical (Lofthouse et al., 2015). Is solar power economically reliable? Currently, most of the governments are providing incentives and subsidies to encourage more generation and adoption of solar energy. However, for solar power to be economically viable it needs to be independent of government financial incentives, mandates and subsidies Singh & Fernandez (2015) suggest.

Statistics from the US Energy Information Administration (2013) suggest that the levelized cost of solar (LCOE) power is 125.3 dollars per megawatt-hour compared to 75.2 and 95.1 dollars for natural gas and coal plants respectively. The LCOE is the measure that is used to find the cost of power of a specific period (Branker, Pathak & Pearce, 2011). According to the International Renewable Energy Agency (IRENA), the LCOE is the price of electricity required for a project where revenues would equal costs, including making a return on the capital invested equal to the discount rate (Irena, 2012).

Using the following the following formula, the LCOE for solar power can be calculated at present and projections for the future made.

LCOE =  where I is the investment expenditure, t is the number of years, E is the electricity generation, F is the fuel expenditure, n is the economic life of the system and r is the discount rate.

Therefore, solar power is not economically reliable currently despite the decline in the cost of the system. The LCOE remains high and will take several years for it to become competitive and hence financially viable (Irena, 2012).

Can solar power consistently meet electricity demand? This study has explained photovoltaics require the sun for them to produce electricity. What this means, therefore, is that generation of electricity only takes place during the day. Furthermore, to generate a significant amount of electricity, it is supposed to sunny and not a dull day otherwise there will be a minimal generation. The power generated needs to be fed to the grid or stored in a battery for future use. However, there is the problem associated with storage. Therefore, according to Goetzberger, Knobloch & Voss (1998), the solar power system cannot consistently meet demand since its generation is solely dependent on the light intensity of the sun and during night time there is no generation, therefore, requiring booster power system.

Therefore, solar power systems are not reliable due to their high cost and significant high LCOE. They are also dependent on government subsidies which over the years have proven to be unsustainable and a heavy burden to taxpayers.

Sufficiency of Solar Energy Systems

How sufficient is solar power on a small-scale? As was seen from the literature review, solar power was first used for domestic purposes which were small scale in nature. The figure below shows installations of solar power systems.

Figure 1: Solar installation (Ray, 2013)

The graph above shows the number of solar power systems that were installed from 1995-2011. The trend on the chart is an increased number of installations. Therefore, this suggests that most people are installing solar power system to try and attain self-sufficiency of power (Wett, Buchauer & Fimml, 2007). Also, from the literature review, we saw that solar power systems are associated with low maintenance cost, this factor makes it sufficient in small-scale (Greenmatch.co.uk, 2017).

Solar power has been incorporated in various devices in small-scale such as satellites, watches, radios, and other small gadgets Patel (2005) explains. They have done this with great success, therefore, raising the sufficiency of solar power on small-scale consideration. It is necessary to note that small-scale generation of solar power ranges between 0.1-5.0 kilowatts per hour.

However, is solar power sufficient on a large-scale? Large-scale generation of solar power means the generation of several megawatts (Wadia, Alivisatos & Kammen, 2009). Due to the reduced efficiency in photovoltaics as stated in the literature review, the amount of electricity produced by the solar system is lower compared to that produced by coal. Therefore, to ensure increased production, the solar system configuration requires larger space for mounting or laying of the panels. There is also the problem of storage which has been overcome by connecting the solar energy system to the grid as explained by Ton et al. (2008). Therefore, the sufficiency of solar power on large-scale is dependent on proper storage of the power plus the demand.

Affordability of Solar Energy System

Affordability is the ability of the involved parties to install and maintain the system without suffering economic loss. Is solar power becoming more affordable? The following graph shows the trend of cost of solar panels. From the graph, it is evident that the cost per watt of solar panels has decreased and the trend is expected to continue until it becomes competitive as mention by Devabhaktuni et al., (2013).

The affordability of solar power is further boosted in some countries by rebates offered by governments and utilities. These deductions help reduce the cost of installation making solar energy system more affordable (“Is Solar Power Affordable?”, 2018). Furthermore, as a way to encourage more people to install solar power systems, some governments provide avenues for individuals to sell their solar renewable energy credits increasing the affordability of solar power.

Figure 2: Decline of solar panel prices (Ray, 2013)

What will ensure solar power remains affordable? Statistics show that solar power is becoming affordable, but everyone needs it remain affordable forever. The installation cost is what makes solar power expensive as was discussed in the review of the literature. Therefore, there is the need for continued technological developments in the field of photovoltaics that will ensure the cost of manufacturing the cells is reduced considerably (“Small-Scale Solar Power is on the Rise”, 2017). Also, according to Kaggwa, Mutanga & Simelane (2011), with improved technology, the efficiency of the solar cells can be maximized to close to 100 percent which means that the cost of generating will go down hence the maintaining affordability.

Safety of Solar Energy System

The safety of solar energy system can be categorized into two; safety associated with the power and that of its effect on the environment. Therefore, how safe is the use of solar energy? Just like any other power generation, solar power systems generate electricity which can be very detrimental if not handle with care Lee (2018) concurs. The conception that some people may have about power from a battery being safer than the grid power is wrong. There is no safer power and all forms of electricity especially those above 30-kilowatt-hour should be handled with care to avoid shocks.

Solar power systems use batteries to store power. These batteries produce hydrogen when they are being charged or discharged. When hydrogen combines with oxygen, and a spark is introduced the result is a volatile explosion that may cause injuries and fire (“Safety Concerns with Solar Power System”, 2018). It is, therefore, necessary to ensure the plugs of the battery are well fitted and insulated when charging to avoid such occurrences.

Are solar power systems environmentally safe? The term renewable means that no resources are broken down. Solar panels once manufactured will not cause any emission to the environment hence they are considered a clean form of energy. Nevertheless, the manufacture of photovoltaics has a considerable effect on the environment. According to Kazmeyer (2017), the manufacture of solar panels results in greenhouse gases that are by far more potent than carbon dioxide in trapping heat such as nitrogen trifluoride. Furthermore, there is also, the hazardous byproducts such as the silicon tetrachloride. This toxin is capable of poisoning the ground making it unsuitable for growth of plants. Kazmeyer (2017) reveals that one ton of silicon used to make photovoltaic cells produces four tons of silicon tetrafluoride.

Conclusion

Summary

Photovoltaics are the building blocks of generation of solar power through their ability to convert sunshine into electrical energy. The solar energy system is a clean source of energy with minimal effect on the environment.

The photovoltaics cells have a lower efficiency compared to coal or natural gas hence they often require much larger space than the other conventional forms of energy. Their average efficiency is at 30 percent.

Solar power systems are currently not economically viable since they depend on government subsidies and mandates. As such, this reduces their reliability. The LCOE of the solar energy system is considerably high thus further compromising its reliability.

Solar power systems have proven to be sufficient for both small-scale and large-scale production albeit the former is not yet well developed. For the better part of the century, solar panels were costly, but the prices have since reduced and are continuing to do so as new technologies are incorporated.

Just like any other power system, solar energy system should be handled with precaution and safety always observed since hazards may occur.

Remarks

The solar power system is an exciting prospect that should continue to be looked into as an alternate source of power. Scientists believe that with the right technology, the world could get all the energy it needs from the sun. Therefore, extensive research should continue in the field of photovoltaics to try and raise their efficiency even to 100 percent should it be possible so that they can yield maximum energy. Also, new technologies on storage of power need to be discovered so that the generated power is not lost.

Another fruitful area of research would be the design of materials that are reactive to very low light intensity. With such technology, solar power will be generated even at nights using the low light intensity from the sun reflected by the moon.