It is well known that the planet Earth is facing multiple problems, such as climate change and overpopulation. Since humans are the source of these problems, scientists have looked for a way to solve them. One of the proposed solutions is to utilize solar energy and reduce our dependence on fossil fuels.
While solar power has been around for many years, its effectiveness has been limited by the fact that most solar panels are only capable of generating electricity about half the time. This occurs because the sun doesn’t always shine brightly enough to provide enough energy for a sustainable period of time.
This issue has been addressed in part by scientists from the Department of Energy (DOE) who have developed systems that can store solar energy for use in times of darkness or low-sunlight conditions. Several types of solar energy storage systems exist, such as photovoltaic energy storage and compressed air energy storage. Each type has its advantages.
The most basic form of solar energy storage is the photovoltaic (PV) cell, a device that converts light energy directly into electrical energy. The conversion is a form of photochemical reaction in which photons (which are particles of light) excite electrons in the material that makes up the cell. This allows the electrons to migrate to the terminals (positive and negative) where they can be collected and used to power electrical appliances.
The challenge with this type of solar energy storage is in finding a way to interface with the electricity grid so that the generated electricity can be fed back into the grid at the same time. For this reason, PV cells are not usually used for standalone applications, but rather for situations in which the generated electricity can be fed into the grid.
PV cells are more efficient at converting light energy into electricity than most other forms of solar energy storage, which makes them a preferable choice for those looking to generate a significant amount of electricity. As a result, a wide range of residential and commercial applications for solar power have sprung up, including solar-powered calculators, digital clocks, radios, and even some small appliances such as refrigerators and air conditioners. Most importantly, the widespread use of PV cells has allowed households to generate their own electricity and become less dependent on power companies. This has led to major cost savings for consumers and reduced our collective carbon footprint.
Compressed Air Storage
The second type of solar energy storage is compressed air storage. In this case, the electrical energy is generated as a result of the heat absorbed during the day by the cooler molecules in the air. This type of air storage is more efficient than PV cells in that it requires fewer moving parts (i.e., it doesn’t need to be mechanically driven).
To be clear, compressed air has always been a form of energy storage that has been around for centuries. This type of air energy storage works by having a pair of thermally coupled reservoirs—one hot and the other cold. During the day, ambient air is pulled into the system through an air intake, where it is heated as it flows between the two chambers. The intake is typically placed in close proximity to a heater, which makes it easier for the hot air to enter the system. As a result of the heat, the air in the chambers will begin to expand. This expansion causes the chambers to mechanically couple to one another through a connecting rod, which connects the two chambers. The chambers are also usually fitted with a weight or a balloon to ensure they always stay in mechanical contact with one another and are unable to move independently of one another due to the pressure imposed by the expanding air inside.
The challenge with this type of air energy storage is in developing a practical and cost-effective design that can withstand the extreme temperatures (often near or above 100 degrees Fahrenheit) associated with air compression. While it is possible to build an airtight and/or fireproof enclosure for an air energy storage system, these devices are usually costly to manufacture and operate. As a result, while this type of energy storage has been proven to work, its practical use is often limited to large-scale applications such as utilities and industries.
The most recent advance in solar energy storage has been the use of ferrite magnets. These magnets can retain their magnetism even when placed in extreme temperatures, making them ideal for use in air-cooled applications such as solar-powered vehicles or airships. (The term “air-cooled” indicates that the engine or other electrical device generates its own source of heat as a result of the motion it performs, which is then removed by cooling the engine with ambient air.)
The challenge with magnetic storage is in designing a practical mechanism for storing energy. Like other forms of solar energy storage, ferrite magnets can operate more efficiently when placed in direct sunlight. For instance, the magnets in a typical solar-powered vehicle will only retain about 80% of their capacity at temperatures between 30 and 40 degrees Fahrenheit and will degrade significantly at higher temperatures. This makes ambient air temperature an important factor to consider when sizing a ferrite magnet for a specific application. As a result, while magnetic storage is a promising approach to solar energy, it has not yet been widely adopted due to its limited application and the fact that it is more costly than most other types of solar energy storage. Nevertheless, its use will no doubt continue to grow as the demand for clean energy sources grows.
What Is Needed To Make Solar Energy Reliable?
To this point, we have covered the basics of how solar energy works and the different types of systems that can be used to store it. While this information is important, it is also necessary to understand what is needed to actually make the technology useful.
Firstly, we need to look at the production process of solar power in order to determine how much energy we actually have at any given time. For this reason, solar scientists and experts have developed several terms to help accurately describe different stages of the process.
The first and probably the most widely known term is “concentration,” which simply refers to the process of gathering solar energy. Concentration can occur either at the top or the bottom of a photovoltaic cell, though it generally happens at the bottom. (The top of a photovoltaic cell is where the light enters the device. The bottom is where the electrical energy is generated as a result of light striking the device and causing electrons to move around.)
Secondly, we need to think about how we intend to use the solar energy that we have collected. In some cases, we may want to use the energy immediately to power an appliance or run a small electrical device. In these situations, we typically need small solar panels or photovoltaic cells. However, if we want to run a larger electrical appliance, such as a refrigerator or an air conditioner, then we will require a large solar array, which could consist of many interconnected photovoltaic cells or panels.
If we want to power an automobile using solar energy then we will need a much larger solar array than for a refrigerator or air conditioner. This is because the larger the array, the greater the overall energy produced. The greater the overall energy available, the greater the range of vehicles that can be powered using solar energy. (Small solar panels or cells can be used to power small appliances such as refrigerators or air conditioners, but if we want to power a larger electrical appliance, such as a car or boat, then we will need a larger array.)
Finally, we need to consider the impact that we want our energy consumption to have on the environment. If we want a low impact, then we will need to become more energy efficient. This can be done in a number of ways, including lowering our energy consumption and/or purchasing more energy-efficient appliances. (For instance, in the case of air conditioning, the seasonal use of energy-saving appliances can help reduce our impact on the environment.)
In most cases, we will need to look at all these factors (i.e., the type of equipment that we have, the energy source, and our intended use) in order to choose the “best” type of solar energy conversion system for our needs.