Understanding Alternative Energy Sources and Their Impact
Alternative Energy
Although routinely identified as hard-working or with work, physical work is an entirely different matter.
Mechanical Definition of Work: The product of a strength for the journey. The work can be 0 if the force is 0, i.e., no force, displacement is 0, or if they are perpendicular force and displacement. The work will be negative if the angle is between 90 and 270 degrees, where the cosine is negative, and therefore the product is negative. Thus, mechanical work can take any value.
Thermodynamic Definition of Work: The work done by the expansion of gas. As this is a gas expansion, work is the product of the pressure exerted on a gas by its volume change. As the pressure cannot be 0, the work will be 0 if there is no change in volume, i.e., if the gas remains at constant volume. If expansion is positive, the volume increases; if there is compression, the volume decreases, and the work is negative.
Both mechanics and thermodynamics involve movement, and what is most important is that work is something that is done.
Energy is a property of bodies, defined as the ability of a material system to do work.
Kinetic Energy: The energy that a body possesses by virtue of its motion, proportional to the mass and the square of its speed. Doubling the mass doubles the energy; if its speed doubles, its energy quadruples.
Elastic Potential Energy: The energy that an elastic body has when it is deformed, proportional to the square of the deformation produced.
Gravitational Potential Energy: Near the ground, it is proportional to the mass and the height of the body above the ground.
Electric Potential Energy: The energy that an electric charge has when in the presence of other electrical charges, proportional to the electric charge. Remember that matter is made up of charged particles, so any electric charge is significant.
These are classical mechanical energy types derived in the 19th century. At the beginning of the 20th century, the development of the theory of relativity introduced the concept of rest mass energy, providing equivalence between mass and energy, where mass times the speed of light squared equals the rest energy.
This follows the principle of conservation of energy, which states that energy is neither created nor destroyed, only transformed.
A body can only lose or gain energy when work is done on it; that work is simply the transfer of energy from one body to another, maintaining overall energy at 0.
The first law of thermodynamics states that the work output can never equal the energy that the system has; it must always be lower. The second law tells us that there is always a loss of energy when work is done. This does not mean that energy is lost; rather, that part is converted into heat that cannot be used.
The energy types mentioned above can sometimes combine (like Goku and Vegeta), leading to other types of energy that are only combinations:
Electromagnetic Energy: Electrical energy transmitted by electromagnetic radiation.
Internal Energy: The sum of all the energy of a system.
Binding Energy: Also called chemical energy, found in the bonds of molecules, due to the attraction of charged particles.
Thermal Energy: The kinetic energy of atoms and molecules.
Nuclear Energy: The energy that holds together the atomic nucleus and is the energy of rest mass, as the nucleus has less mass than its constituent particles.
In the International System, the Joule (J) is used, which is the work needed to transport 100 g one meter, a small unit.
Calorie (cal): The energy required to raise the temperature of one gram of water by one degree Celsius, equivalent to 4.184 J.
Calorie (Cal): A unit used in dietetics, although increasingly less so. Companies in refrigeration, when discussing air conditioning or freezing rooms, refer to BTU, which is equivalent.
Kilowatt-hour (kWh): Used in electricity consumption, equivalent to 3.6 million J.
When generating electricity, two special units are used: the ton of oil equivalent and the ton of coal equivalent, each serving as a standard for generating electricity.
Obtaining Energy:
Primary energy is that which is found in nature and exists in its natural state, but most often cannot be exploited directly. The most important sources are fossil fuels and energy minerals (oil, coal, natural gas, and uranium). Others that have not been subjected to transformations include the Sun, wind (one of the first energy sources used by man in navigation and windmills), tidal forces (starting to be used from the 20th century), waves caused by wind (and in turn by the Sun), geothermal heat from the Earth, and biomass obtained from living things, which is now used as fuel.
Secondary Energy: When primary energy is converted into useful energy for humans directly. These changes can be physical (such as the distillation of petroleum), chemical (like the cracking of coal or oil), or biochemical (such as fermentation of biomass). This is done to obtain fuel or electricity. Sometimes fuels for electricity are produced.
Production of Electricity: There are five ways to produce electricity, but not all are pure.
The first is piezoelectricity, which consists of obtaining power by pressing certain materials and is still in a very elementary stage.
The second is the battery, which, having a few joints, is called a battery, an electrochemical generator of electricity with several types: rechargeable, non-refillable, fuel, and alkaline.
The third way is using photovoltaic panels, which generate electricity directly from sunlight.
The most common method is using an electric generator, which essentially consists of a boiler, turbine, generator, and condenser. The water boiler burns fuel to evaporate water; the steam moves the turbine, and the water vapor condenses in the condenser. The water is then returned to the boiler without cooling to maximize efficiency. Hydroelectric plants operate similarly, where the turbine is driven by falling water. Wind turbines operate as the wind moves the blades, while tidal turbines are driven by the rise and fall of tides.
A turbine blade is a series of properly oriented blades that allow steam or other moving fluids to pass between them. In a closed system, the fluid enters and exits, while in an open system, there is a fluid outlet. The generator consists of a coil of copper rotating between the poles of a magnet, generating electricity as it spins.
Alternative Energy:
The first is wind power, which involves the production of electricity from wind, obtained by wind turbines similar to 3-bladed turbines. Their operation is similar to previous generations but includes a multiplier system that accelerates shaft rotation. The spinning blades, moved by the wind, rotate at around 3 to 6 rpm, while the generator speed is around 1500 rpm. The turbines can be isolated and tend to be smaller, called microgenerators or minigenerators, depending on the amount of power supplied to a local area. Alternatively, wind farms can be installed, which supply electricity to the general electricity network. The advantages of this type of energy include being clean, non-polluting, and quick to install, typically completed in a few months. Land used for wind farms can often serve other purposes, and the size of the wind farm can be scaled according to energy needs. The disadvantages include the need for specific locations with prevailing winds, the risk of turbine damage in strong winds, and the inability to store energy. If there is no wind, there is no electricity, and the visual impact of wind farms can be significant, often located in protected areas. Additionally, the distribution of the electricity produced can be expensive, and large areas are required for wind farms.
Solar energy harnesses energy from the sun and includes several types: photovoltaic conversion (using solar panels to convert light into electricity), solar thermal energy (for hot water), and solar thermal electric (using solar ovens and mirrors to generate electricity). The advantages of solar energy include being clean, having a low ecological impact, and high performance, reaching temperatures of up to 300 ºC. It requires low maintenance costs, as systems are automated. The disadvantages include the need for sites with high insolation rates, weather instability, and high initial costs for creating solar power plants.
Hydropower is divided into run-of-river and reservoir systems, where a dam is created, and water flows through a tube, moving the turbine. The advantages are clear: water can be stored, and the infrastructure can also be used for human consumption or irrigation, preventing floods and promoting tourism. Maintenance costs are very low. The disadvantages include the high costs and time required to build dams, significant environmental impacts, and dependence on weather conditions; prolonged droughts can severely affect output.
Tidal energy is harnessed on coasts where there is a significant difference in height between tides, typically requiring a difference of 5 to 6 meters.
Geothermal energy utilizes heat from the Earth and is only feasible in volcanic areas.
Biomass power plants use plant material instead of fossil fuels, burning specific crops for energy.