Solar Energy: a History and Analysis

Despite the fact that people think solar energy is something that is fairly new, we have known about it and how to harness energy from the sun. The discovery of solar energy as a concept starts in the early 1800s. In1839 Alexandre Edmond Becquerel discovered the photovoltaic effect, which explains how electricity can be generated from sunlight. He claimed that “shining light on an electrode submerged in a conductive solution would create an electric current.” Despite this discovery, the technology wasn’t there yet to use solar cells as a source of energy. in 1876. William Grylls Adams and Richard Day, a student of his, discovered that when selenium was exposed to light, it produced electricity. The cells were inefficient but it proved that without heat or moving parts, light could be converted into electricity. In 1941, Russell Ohl invented the solar cell, and what we know as solar energy today was born. In 1953, Calvin Fuller, Gerald Pearson, and Daryl Chapin, discovered the silicon solar cell. The cell produced enough electricity to run small electrical devices. Three years later in 1956 the first solar cells are available commercially. The cost however is too much for the average person to utilize them. The cost at the time was $300 for a 1 watt cell, making it expensive to use solar energy. Despite this, the solar cells were still used in things like toys and radios, making them the first items to have solar cells available to consumers. From the 1950s to the 1960s, satellites were powered by solar cells and in the late 1960’s solar power was the standard for powering satellites. In the 1970’s a way to lower to cost of solar cells was discovered. This made the cost of solar energy $20 per watt. From 1970 to 1990, solar cells began showing up on railroad crossings and in remote places to power homes. Today, solar energy is more popular then it ever was. It is commonplace to see solar panels and by extension, solar energy to power homes. Today, solar panels only utilize a small percentage of the suns energy. However, it still is a good amount of energy that we can convert today using solar panels. If solar panels were able to utilize all of the suns energy, less then a percentage of that energy would be more then enough to satisfy the U. S's energy needs. Because of this, the future of solar energy looks bright indeed. As more technological advancements are discovered that make solar panels more cheap and efficient, we will be one step closer to achieving this goal. In addition to large amounts of energy, solar energy has the benefit of not producing any greenhouse gases or carbon dioxide. This makes solar energy crucial in combating fossil fuels and by extension, climate change. Finally, solar energy helps create jobs as society shifts away from fossil fuels and as result, jobs tied to them disappearing as well. Solar energy is a resource that has a lot of potential to solve energy crisis problems in the world and powering our society for years to come. But how does solar energy work? What is the process, and how can it be improved. In the next section, we will cover the basics behind how solar energy works. We will also talk about some ways that are being looked at to improve the efficiency and cost of solar energy as well. Understanding solar energy starts with the solar panel. A solar panel is a rectangular object that looks like glass and this is where most of the magic of solar energy happens. Solar panels work by allowing particles of light to know electrons free from atoms, producing electricity. Another main component of a solar energy setup is the inverter. An inverter can provide benefits such as system stats, ground fault protection, and maximum power point tracking. The main role of an inverter, however, is to convert direct current(DC) to alternating current(AC). As sunlight hits the solar panel, electrons are knocked free of atoms and electricity is produced. Specifically, the type of electricity produced is DC electricity. Most of the things we use everyday such as lights and TVs use AC current to power these items, as AC is more safer and easier to work with than DC current. So an inverter converts DC current to AC so the electricity produced can be used at all. One main concern people bring up when using solar energy is suggested is what happens at night or during cloudy days when not a lot of solar energy is produced. This problem is solved by a system known as net metering. Typical systems used in places such as houses produces more energy then the amount the user actually needs, so the excess energy is send back into the electrical grid and used somewhere else where it is needed. When this happens, the user gets credit based on the amount of electricity that was sent back in the grid. Costumers can use these credits to draw electricity from the grid during cloudy days or at night so that they still have electricity. Unfortunately, the fact that solar power relies on the sun is its biggest strength and drawback. On one hand, the sheer amount of energy the sun produces means we can easily meet our energy needs. Its biggest weakest however is that you need the sun to hit the panels to produce energy. This means the problem of producing electricity at night needs to be solved before solar energy can be accepted as a true alternative to fossil fuels. This is a very high level look at how solar energy works. There a lot more complex interactions that are not needed for the purpose of this paper. Solar energy itself is a very broad term and can refer to several types of ways to harness the suns energy. In the next section, we will talk about each of these different types of energy and how they work. We will also discuss the pros and cons of each type of solar energy compared to the others. Finally, we will talk about ways each of these types of solar energy are being improved and how they are being used today. Solar energy itself is a very broad term and can refer to several types of ways to harness the suns energy. One type of solar energy are solar electric systems. This type of solar energy uses photovoltaic panels to produce energy. They way they produce energy is fairly simple. As sunlight hits the photovoltaic panel, electrons are knocked free of atoms and electricity is produced. Specifically, the type of electricity produced is DC electricity. Most of the things we use everyday such as lights and TVs use AC current to power these items, as AC is more safer and easier to work with than DC current. So an inverter converts DC current to AC so the electricity produced can be used. To maximize the amount of energy produced, photovoltaic systems try to maximize the amount of time they face the sun. Achieving maximum efficiency is done through the use of a solar tracker. A solar tracker is a device that orients a photovoltaic panel towards the sun. This can lead to increase in energy production by up to as much as 20% in the winter and 50%. This is done through the use of a solar tracker. A solar tracker is a device that orients a photovoltaic panel towards the sun. This can lead to increase in energy production by up to as much as 20% in the winter and 50%. Current developments involve changing the makeup of solar cells. Perovskite is a recently discovered material that is inexpensive compared to the crystalline silicon material that most photovoltaic panels are made up of today. Using perovskite can cut the cost of producing photovoltaic panels by up to 27% depending on the size of the systems. Efficiency is obviously one of the main driving factors for choosing a photovoltaic system. Efficiency and price usually go hand in hand, so the most efficient photovoltaic panels will also be the most expensive. The electrical efficiency of a photovoltaic cell represents how much electrical power a cell can produce for a given isolation. Isolation is simply the amount of solar energy a photovoltaic panel receives at any given time from the sun. Currently, the most efficient photovoltaic panels had an efficiency of 46%. Currently the industry standard for efficiency of solar panels is between 12% and 18%. There are various cons to photovoltaic panels as well. One con is the cost of producing the photovoltaic panels in the first place. Photovoltaic panels currently cost thousands of dollars to install modest systems used in homes. Photovoltaic panels increase in cost the more efficient you want your photovoltaic panels to be. Panels that have the top efficiency currently available can cost millions of dollars to install large systems. One problem with photovoltaic panels is the waste that can be produced if they are not properly disposed of. Photovoltaic panels themselves don’t produce any waste when generating energy. However, after a panel has gone past is life cycle or has broken, it needs to be disposed of. Another problem with photovoltaic panels is the waste that can be produced if they are not properly disposed of. Photovoltaic panels themselves don’t produce any waste when generating energy. However, after a panel has gone past is life cycle or has broken, it needs to be disposed of. The photovoltaic panel itself is made up of materials such as silicon, which can damage wildlife and the environment if not properly disposed of. There is also the materials that are used to install the photovoltaic panels themselves, which are also toxic to the wildlife and environment. However, as long as they are properly disposed of, they can be recycled into new photovoltaic panels and now waste is produced as a result. The pros of photovoltaic systems are numerous. One pro of photovoltaic systems is that have a large range of applications. Photovoltaic systems can be installed on any building that has enough roof space to support such a system. There are a variety of systems that range in cost and efficiency to meet the varying degrees of electrical needs for the user. Another pro of photovoltaic systems is that they last for a long time and payoff in terms of cost quickly. An average photovoltaic system to power a home can last from anywhere to twenty to twenty-five years. That means that the user doesn’t have to worry about the upkeep for the system for a very long time. Another pro of photovoltaic systems is the payoff of them is generally fast. From the time someone installs a photovoltaic system, it only takes anywhere from half a year to a year for them to offset the cost they had to pay to install the system itself. As photovoltaic systems get even cheaper and more efficient, the period of the time these systems are going to last increase while the time needed for the user to offset purchase cost is going to decrease. Overall, photovoltaic systems dominate the solar market for a good reason. Despite some negatives associated with them, they can be avoided if proper permutations are taken. They have a good chance to get even better over time and to continue dominating the industry as a result. Overall, photovoltaic systems dominate the solar market for a good reason. Despite some negatives associated with them, they can be avoided if proper permutations are taken. They have a good chance to get even better over time and to continue dominating the industry as a result. Another type of solar energy is solar hot water. Solar hot water is a technology that has been used since the 1900s. Solar water heating is the conversion of sunlight into heat for water heating using a solar thermal collector. A solar thermal collector is similar to a photovoltaic panel in that they both collect sunlight and convert it into energy. There are two types of solar thermal collectors. They are flat panel collectors and evacuated tube collectors. Flat plate collects are the more common out the two. Flat panel collectors consist of a heat absorbing plate made out of copper or aluminum. A flat panel collector absorbs incoming solar energy from the sun and then converts it into heat energy. This heat energy can then be used to heat water up for practical uses. Flat panel collectors are cheaper to install, easier to design, meet acquitted consumer demand to heat hot water for everyday use, and last a long time. The size of the flat plate collector depends on the size and amount of hot water needed on a user basis. One bad thing about flat plate collectors is that they can be expensive depending on the amount of hot water a user needs. The initial price to install the system itself is more expensive then conventional gas and oil heaters. A bad thing about flat plate collectors is that they can be expensive depending on the amount of hot water a user needs. The initial price to install the system itself is more expensive then conventional gas and oil heaters One good thing, however, is that flat panel systems will reduce the overall amount of gas consumed over its lifetime. Most flat panel systems pay themselves from anywhere between 5 to 10 years depending on the size of the building and the amount of hot water consumed by the user. The other type of solar thermal collector is the evacuated tube solar collectors. Unlike flat panel collectors that use liquid to collect heat energy, evacuated tube collectors use pipes that conduct heat to capture heat that way. As solar energy from the sun hits the evacuated tube collectors, the pipes heat up and produce energy. The heat from the pipes is then transferred to a hot water system where it is then used to heat the hot water for use. There are both pros and cons to using flat panel collectors and evacuated tube collectors. For example, flat panel collectors tend to lose more heat compared to evacuated tube collectors the hotter the environment they are in is. This means that flat panel collectors are not advised for places with high average temperatures such as Nevada or Arizona. Another example is that evacuated tube collectors have a higher efficiency per square meter, making them better for places and buildings that have limited roof space for the collectors. Finally, evacuated tube collectors perform better in areas with low temperature or cloudy overcasting most of the time. There are variety of reasons why someone would want to choose evacuated tube collectors over flat panel collectors and the decision is usually determined on a case by case basis. Solar hot waters main purpose is to heat hot water for later or immediate use. As a result, it can be applied anywhere where hot water is desired or needed. There are certain buildings that main be off the grid, too far away from the grid to meet their energy needs, or operating electrical hot water heating systems might be too expensive. Solar hot water heaters are excellent for buildings that meet any of this criteria. Despite having a more specific use then photovoltaic systems, solar hot water systems still have the opportunity to take up a large part of the solar electric industry. There are a lot of industries that could benefit from alternative ways to heat water instead of just oil and gas. Because of this, solar hot water energy has a bright future ahead of it and will see more use as it becomes even more cheaper and efficient to use solar hot water systems. Another type of solar energy is solar pool heating. Solar pool heating is an even more specific application of solar energy then solar hot water energy was. Solar pool heating works very similar to solar hot water it terms of how solar energy from the sun is converted into heat. They both also use heat energy to heat water so they are very similar. The way the solar pool heating system works is very simple as well. A solar collector on a roof captures energy from the sun and stores the heat energy in tubes. Meanwhile, at the same time water is pumped from the pool itself and is run through the heated tubes. The heated tubes heat up the water and the heated water is pumped back into the pool. This process repeats indefinitely and results in the pool itself losing less heat due to evaporation and temperature changes. One pro of solar water pool heating is that it is fairly cheap to have a system installed for a pool of average size, with most solar water pool heating systems having competitive prices with conventional pool heating systems. However, there is one main con to solar pool heating systems. Since solar energy is not collected during cloudy days or the night, this can lead to inconsistent heating for the pool itself. This can be solved by making the solar pool heating system itself use power from the grid itself during cloudy days or during the night. Finally, another con for solar pool heating systems are that they have a specific compared to more general systems that can do the same thing. Photovoltaic systems generate electricity that can be used for all the buildings electrical needs while even solar hot water systems can generate hot water that can be used to heat pools as well. Why ever install a solar pool heating system then? Another pro of solar pool heating is that they are marginally cheaper then other systems such as photovoltaic systems and hot water systems. This is a good thing for someone who isn’t ready to fully commit to solar energy, lives in an area where solar energy isn’t at its most efficient, or just wants a cheap way to heat only their pool. Overall, solar pool heating is probably the most specific and as a result, least useful type of solar energy out of the ones discussed in this paper. However, it is good for people who want to try out solar energy without committing or for people who just want to heat their pools cheaply. Solar pool heating has a niche market of people right now and it could disappear as more general forms of solar energy such as photovoltaic and solar hot water become cheaper or more effective. The fourth and final type of solar energy is concentrated solar power or CSP. Concentrated solar power is the process of generating solar power by using mirrors or lenses to concentrate a large area of sunlight onto a small area. The concentrated light is converted to heat which feeds power to a heat engine. Concentrated solar power is used in situations where the amount of power needed is on a large scale then the needs of an average house owner or even small to medium sized companies. The amount of electricity produced by concentrated solar power is on par with the amount of electricity needed to power thousands or even millions of homes in the United States. The focusing of the solar energy is done with a large reflective mirror usually, however, there are other ways to focus solar energy onto a small area. These include things such as troughs, towers, reflectors, and dishes. Concentrated solar power accounts for less than 2% of the solar industries infrastructure. There is a reason for this as well. Concentrated solar power is magnitudes upon magnitudes more expensive then photovoltaic systems. In addition to this, photovoltaic systems have seen a rapid decline in price and increase in efficiency, making one of concentrated solar powers main advantages over the solar energy types matter even less. However, concentrated solar power systems have one main advantage over every other type of solar energy that still makes it worth considering in the future. Concentrated solar power systems have the to store heat and solar energy in molten salts. This allows the concentrated solar power system to continue generating energy despite the time of day unlike photovoltaic systems which are unable to produce electricity during cloudy days or during the night time. Overall, concentrated solar power is the most interesting application of harnessing solar energy because it can work in either day or night. However, the cost of implementing such a system isn’t worth it when cheaper alternatives like photovoltaic systems are currently available for consumers. Concentrated solar power still has it applications for when someone wants to generate a large amount of power in a small space despite the time of day. Now that we know about the four basic types of solar electricity, we can start comparing them to each other directly to truly know their strengths and weaknesses. Let us start with photovoltaic systems, as they are the most widely used and general out of the types of solar energy available to us today. Photovoltaic systems have two main benefits. First, photovoltaic systems produce electricity that can be used for the entire system. Meaning, if a homeowner uses a photovoltaic system for their house, they can use it to replace everything in their house that uses electricity, including electric hot water heating if they have it, which, gets rid of the need of using solar hot water while having a more general system for your house. Another pro of photovoltaic systems is that any excess electricity gets put back into the electrical grid. There are some downsides to photovoltaic systems compared to the other types of solar electricity. First, while photovoltaic systems are more general and generate electricity for the entire building, it is more expensive and wasteful if all a costumer wants or needs is less. If a costumer only needs thinks like heating hot water or their pool, it would easier and cheaper for them to go with hot water power or solar pool heating. This same problem exists with solar hot water and solar pool heating. A solar hot water system is more generalized then a solar pool heating system. Meaning, a solar hot water system could take care of a systems hot water needs, including heating a pool if set up correctly. This means that it almost beneficial to get a solar hot water system to have a system that does more instead of getting a solar pool heating system that doesn’t less. The only reason you would need to get a solar pool heating system is if that is all you need. Other wise, it is almost always beneficial to get a more general system that covers a lot more. One con that all solar energy types suffer from is that they can’t be used to generate electricity during the night. These means that effectively energy can’t be generated 50% of the time when using solar energy. This is a problem that will need to be circumvented if the industry hopes to be embraced by the rest of the world as an alternative to fossil fuels. Now that we have done some base comparisons between the different types of solar energy, lets analyze each type of energy and rank them from the most useful to the least useful. Photovoltaic energy is easily the most useful type of solar energy and it dominating the majority of the shares in the solar energy backs this up. Like it has been state before multiple times throughout this paper, Photovoltaic energy is the most generic solar energy type out of all of them. Photovoltaic energy not only can be applied to all the use cases the other types can be applied to, but it does it while being more generic as well. Meaning, photovoltaic energy can do all the other jobs the solar energy types can do while still being able to apply itself to other applications that the other solar energy types can’t do on their own, like powering a house with electricity. These reason make photovoltaic energy the most volatile and useful type of solar energy by far. Next up is solar hot water energy. Solar hot water energy is the next most specific type of solar energy. Solar hot water energy is mainly used to heat water for various applications. Despite it pretty specific, solar hot water energy still has more general then solar pool heating, which can obviously only be used to heat pools. Solar hot water energy has the potential to heat a pools water if set up correctly like how photovoltaic energy can take care of heating up water if setup correctly. Next solar pool heating is the next useful type of solar energy. Now, solar pool heating is a really specific type of solar energy that only has one type of application, heating pools. Despite this, solar pool heating is the second to last most useful type of solar energy because of the least useful type of solar energy, concentrated solar power.

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