Most people are pretty familiar with the terms solar and energy. After all, we live in a world where electricity is readily available and running water is taken for granted. However, not all forms of solar energy are created equal, and understanding the differences can help you make the right decision for your needs.
Solar Thermal Energy
This type of energy is created by concentrating heat energy from the sun using mirrors or lenses. This method was first used in the early 1900s, and it has since been shown to be incredibly reliable and efficient for generating electricity. As a result, many utilities have switched to solar thermal energy as their preferred option for powering their infrastructure.
The most common type of solar thermal energy is known as concentrated solar power, which uses lenses or mirrors to focus sunlight on a boiler, dish, or tank containing cool water or steam. These devices can produce energy even at night or when the Sun is not directly above it, and as a result, they are called solar electricity generators (SEGs).
The advantage of concentrating solar power is that it can be designed to produce more energy than you’d get from an ordinary solar panel system. For example, a 1000 Watt peak solar power system would generate about 7.2 million joules of energy per day – not enough to power a home, but more than enough to power an entire small town! A 5000 Watt peak system would produce about 36 million joules per day – more than enough to power an entire city! This high level of concentration is possible because the sun’s heat is so great that even one day of sun exposure is more than enough to create the power you need for an entire year.
Solar PV Energy
A solar photovoltaic cell is the basic unit that converts light energy from the sun into electricity. The efficiency of these cells varies by manufacturer, but the overall efficiency rating is about 15% when multiplied by the number of cells used to make up a solar panel system. This is much lower than the efficiency of thermal solar cells, but since most people don’t need to generate huge amounts of power on a daily basis, the efficiency difference is not as critical as it would be for high-capacity generators.
Like other forms of solar energy, solar photovoltaic cells generate electricity when exposed to direct sunlight. However, unlike thermal solar energy, the amount of direct sunlight that can be collected and directed towards a photovoltaic cell is limited by the latitude (north versus south latitude) of the area where you live and the time of day (day versus night). In the northern hemisphere, solar photovoltaic cells can only generate electricity during the day, while southern solar cells can generate energy at night as well as during the day. These variations in generation time make solar photovoltaic cells more suitable for baseload power generation than for peak load shaving.
This form of power is generated by converting the falling water of a river into electricity. The World Hydroelectricity Union estimates that there are currently about 500 large-scale hydroelectric power plants globally, which collectively generate about 36 trillion kWh of electricity per year. While this might not seem like a lot, it is more than enough to power the worldwide demand for electricity and meet about 50% of the world’s demand for fresh water.
The environmental impact of large-scale hydroelectric power plants is typically minimal as they typically operate at low speeds and low head diameters. However, the deforestation often caused by dam construction and the flooding that results from large amounts of water being held back by dams can have a negative impact on local wildlife. While it is generally an effective and reliable source of power, hydroelectricity is generally not considered sustainable because the process of generating electricity – especially at a large scale – can have a considerable impact on the environment. However, with careful consideration and planning, hydroelectricity can be a very effective energy source and play an important role in providing electricity to people who need it.
Wind power is perhaps the least studied and understood form of solar energy, but it is also the most versatile and flexible. This is largely because the generation of wind power is highly dependent on local conditions, including the climate and topography of the area where the turbine is located. As a result, the World Wind Energy Association estimates that there are currently about 40 projects currently in progress around the world that will increase the total global capacity of wind-powered electricity generation by about 12 gigawatts (GW) by 2020. This will increase the annual total worldwide installations of wind turbines by about 80 gigawatts (GW).
Like other forms of solar energy, wind power can be used to either store or release energy as needed. This is done either by connecting wind turbines to a grid that provides electricity to consumers or by using superconducting turbines that can both store and generate electricity on demand. Wind power is a good option for locations with mild weather conditions that are suitable for year-round maintenance and operation. However, if your area is prone to severe weather conditions or frequent outages, then this option might not be as viable.
This form of energy is generated by using the temperature gradient between the earth’s crust and its core to heat fluids, which then generate electricity. The world’s largest geothermal power plant, the Tuolumne Valley Solar Energy Project, currently operates at 228 MW and is the result of the collaboration between Northern California public utilities (e.g., Pacific Gas and Electric Company (PG&E)), national laboratories (e.g., Sandia National Laboratory), and private industry (e.g., BrightSource). Another example is the Gleason Arms Project, which has the potential to generate 140 MW of electricity. This project was built in Nevada and began producing power in 2015.
The environmental impacts associated with geothermal energy are typically considered to be negligible. However, the extraction of geothermal resources – especially at a large scale – can result in localized ground water contamination, with about 20 tons of heavy metals (e.g., cadmium, lead, and mercury) being used per day in the US.
This form of energy is, in many ways, the most effective and sustainable of the bunch. Not only is it very reliable and efficient, but it also generates relatively little environmental waste. In fact, the World Nuclear Fission Power Association estimates that there are currently about 20 approved plants around the world that have the potential to generate about 100 gigawatts (GW) of electricity. A 1000 MW nuclear plant would have the potential to generate about 42 gigawatts (GW) of electricity – enough to power a small city like Langley for about a week. In addition, because nuclear energy is generally reliable and therefore baseload power, it can play an important role in reducing electricity bills for consumers. One downside to nuclear power is that it is highly dependent on governmental policies (e.g., finance aid, liability rules) and local/regional circumstances (e.g., geological resources, radioactivity of foundations, existing waste management infrastructure) for its success. For instance, if the government decides to build a few more nuclear plants in a particular area, then the cost of electricity will increase.
What Is The Difference Between These Technologies?
It’s important to always remember that no one source can provide all the answers you might need. While the above list does include some of the most common differences between these technologies, it is not an exhaustive list. For example, while solar thermal energy and solar photovoltaic energy both generate electricity using photovoltaic cells, they are still considered two separate and distinct forms of solar energy.