Energy Resources: A Comprehensive Guide to Conventional and Alternative Sources
Energy: The Foundation of Our World
Energy is the ability to do work. A staggering 99% of the energy used on Earth originates directly or indirectly from the sun. Energy manifests in various forms, including calorific value, electromagnetic, mechanical, potential, and nuclear. While we utilize conventional energy sources like fossil fuels, nuclear fission from uranium, and hydropower, the need for sustainable alternatives is paramount.
Factors Influencing Energy Use
Quality of Energy
Higher-quality energy is more concentrated, while lower-quality energy is dispersed over larger volumes. Even if abundant, low-quality energy has limited practical utility.
Profitability
Profitability is crucial for energy source utilization and is determined by accessibility, ease of operation, and transportation. The price of an energy source directly impacts its profitability.
Energy Systems
An energy system encompasses the processes involved in transforming energy from its original source to its end use. These phases include:
- Capture or extraction of primary energy
- Transformation into secondary energy
- Transport of energy resources
- High energy consumption
A converter is a system component that transforms one form of energy into another for easier transport or use. Each conversion process inevitably involves some energy loss.
Energy Efficiency
Energy efficiency refers to a system’s performance, measured by the ratio of energy supplied to the system and the energy obtained from it (input/output), expressed as a percentage.
Energy Cost
Energy cost refers to the price paid for high energy use. However, hidden costs associated with equipment and facilities involved in the entire energy process must also be considered.
Conventional Energy
Fossil fuels currently dominate the global energy landscape. However, this reliance cannot be sustained indefinitely due to the finite nature of these resources.
Fossil Fuels
The theoretical estimate of the total amount of a fossil fuel or mineral in the Earth’s crust is called its reserve. The amount of a fossil fuel discovered and economically viable to extract is called its proven reserve. Currently, 79.6% of commercial energy used worldwide comes from fossil fuels. Transitioning to alternative energy sources with a lower environmental impact is crucial.
Coal
Coal formed from the accumulation of plant remains in swamps, lagoons, or deltas, undergoing fermentation in the absence of oxygen. Coal is a high-calorific value fuel and one of the most abundant (estimated reserves for 220 years at current consumption rates). However, it is also the dirtiest due to its high sulfur content, releasing significant amounts of SO2 when burned, contributing to acid rain. Coal’s primary use is in power stations to generate electricity. While eliminating thermal power is currently impossible, strategies to minimize its impacts include:
- Substituting coal with fuels containing less sulfur
- Preprocessing fuel
- Designing more efficient thermal power stations
Oil
Oil originated from the mass death of marine plankton, triggered by changes in temperature or salinity. The sediment, along with silt and sand, forms sapropel muds. Both components undergo transformation: organic matter becomes oil, while silt and sand form the bedrock. Oil is transported through pipelines, but large tankers are also used, posing a high risk of accidents. Oil is a dark liquid lighter than water, and in case of leakage, it can spread across the sea surface, blocking oxygen and destroying marine life. Crude oil, a mixture of hydrocarbon gases, liquids, and solids, has no direct application. It undergoes a series of refining processes, known as fractional distillation, where different fractions are separated based on their boiling points. Oil well data are not suitable for consumption and require further treatment.
Natural Gas
Natural gas, like oil, originates from the fermentation of organic matter within accumulated sediments. Its extraction is highly efficient due to the pressure exerted by the surrounding sediments, allowing gas to flow naturally, making its extraction economical. Natural gas is primarily transported through pipelines. It is used directly in homes and industries, and its use in thermal power plants is gradually replacing coal. Natural gas is an ideal fuel for the transition to renewable energy sources.
Nuclear Energy: Fission
Nuclear power, once considered a solution to the world’s energy problems, is now viewed as a dangerous and inappropriate energy source.
Operation of a Nuclear Reactor
The fission of a uranium-235 nucleus by a neutron releases energy and neutrons. These neutrons collide with other uranium nuclei, triggering further fission in a positive feedback loop called a chain reaction. To control the reaction rate, a moderator is introduced between the fuel rods to absorb neutrons without producing new fissions. The primary circuit, in contact with radioactive material, is confined within the main reactor vessel, and the water in this circuit never leaves. The secondary cooling circuit cools the steam generated in the primary circuit. A third circuit liquefies the steam produced in the secondary circuit, with water entering and leaving a deposit or foreign river.
Hydropower
The potential energy of water flowing from mountains to the sea can be captured and converted into electrical energy in reservoirs. Opening the floodgates releases this energy to drive turbines. Hydroelectric power is low-cost and requires minimal maintenance. It does not emit pollution. However, negative aspects include:
- Reduced biological diversity
- Fish migration problems
- Reduced river flow
- Eutrophication of waters
- Geological risks, such as accelerated erosion and sedimentation
Alternative Energy
To assess the potential future use of alternative energy sources, factors such as current availability and cost must be considered. The lack of necessary infrastructure for their use poses a significant challenge for their adoption.
Energy from the Sun
The sun is our planet’s primary energy source, but the Earth intercepts only a fraction of its energy, which is of low concentration.
Passive Architectural Systems
Passive solar design involves building homes that are heated or cooled passively, using techniques like well-insulated walls and roofs. This approach, known as bioclimatic architecture, draws upon traditional architectural knowledge.
Solar Thermal Power
Solar thermal power uses heat from the sun to generate electricity. Sunlight is captured and concentrated using collectors with three possible designs:
- A parabolic dish that focuses light onto a point
- A parabolic trough that focuses light onto a line
- A set of flat mirrors that reflect light towards a central tower
Photovoltaic Solar Power Plants
Photovoltaic solar power plants convert sunlight directly into electricity. Each cell is made from monocrystalline silicon, making it expensive. Photovoltaic energy generates electricity without pollution, noise, or moving parts. The facilities require minimal maintenance and no water. However, disadvantages include the need for ample space, visual impact, and variability in production.
Biomass Energy
Biomass is a renewable, cheap, and clean energy source that can help alleviate the current energy deficit. It is derived from a wide range of products, including forestry, animal waste, and garbage. However, transporting biomass is expensive. The use of stored energy in biomass is renewable if we consider the replanting of trees used for energy.
- Municipal waste contains combustible components. The high cost of modern waste incineration has led to the consideration of reusing the energy generated from combustion.
- Transformation into biofuels: Organic waste can be converted into liquid or gaseous biofuels. Ethanol can be obtained from the fermentation and distillation of grain. Other biofuels include methanol and bio-oils.
Wind Energy
Wind energy uses wind turbines to convert wind energy into electrical energy. Wind energy is a clean energy source that does not emit pollution. However, negative aspects include visual impact, bird mortality, and increased erosion.
Energy Independent of Solar Energy
Tidal Energy
The interactions between the Earth, moon, and sun cause variations in sea level known as tides, from which electrical energy can be obtained. Tidal energy generation is similar to hydroelectric dams, involving the construction of a dam to close a bay and allow the tide to pass through it.
Geothermal Energy
The heat within the Earth’s interior is also a source of energy. In geothermal plants, cold water is pumped through pipes to a certain depth, collecting water vapor that rises under pressure through other pipes. The resulting hot water can also be used for heating and hot water for households. Modern drilling techniques have reached depths of 3,500 meters. While clean, geothermal energy is not renewable, as the thermal energy of the wells lasts only 15 years.
Hydrogen Fuel
Hydrogen is the most abundant gas in the universe. Due to its abundance, hydrogen is considered an eternal fuel. Following the Kyoto Protocol, the decarbonization process has gained momentum, making the use of hydrogen as a fuel increasingly important. The ideal mechanism for hydrogen production is electrolysis, which involves using an electric current to decompose water into its components: hydrogen and oxygen. Another method, with more remote application, is based on the breakdown of the water molecule by direct sunlight (photosynthesis).
Nuclear Fusion Energy
Nuclear fusion involves the union of light nuclei to form a heavier nucleus, releasing a vast amount of energy. For this reaction to occur, the nuclei must be close together, which is only possible at high temperatures, where atoms are in a fourth state of matter, plasma. No material can contain plasma, so the only solution is to store it in magnetic bottles. One of the most advanced magnetic confinement designs is the research reactor.
Efficient Use of Energy
Energy conservation has emerged as a new source of energy savings. One energy-saving mechanism is cogeneration, which involves the combined production of two useful forms of energy. Specific measures related to energy use include:
- Increasing efficiency in the electric system: Innovative power companies have implemented”savings negativ” systems, providing financial support to consumers to purchase energy-efficient bulbs and equipment.
- Valuing the real cost of energy consumed
- Assessing the hidden costs of energy
- Reducing consumption in different sectors: Auto companies are producing smaller, more efficient vehicles. At home, heating and hot water costs are significant.
- Personal energy-saving measures:
- Using public transportation more frequently
- Purchasing energy-efficient appliances
- Increasing the recycling of glass and paper
Mineral Resources
Our society requires a continuous flow of raw materials. Due to their importance, mineral resources have been extensively exploited throughout history. Harvesting techniques have evolved alongside development, from the first useful materials (wood and stone) used in the late Neolithic to the heavy machinery of our century.
Metallic Mineral Resources
.They are used in metal extraction and energy. minerals are removed from those places where the elements are concentrated: the deposits. For a site is economically feasible should contain a high proportion of a particular metal. The holdings of a site are called mines. Once mined metals are rarely found in pure form. The ores are subdivided into: abundant and scarce metals. The operation of a particular mineral depends on its economic interest. The reserves of certain minerals are changing over time: as the demand grows for a particular metal, increasing the exploitation of the mineral that contains it. Subject to the availability of appropriate technologies for this, the mineral resources of the junction can be transformed into reserves. The steel industry is the removal of iron from ore containing it. Depending on the amount of carbon containing iron resulting obtain: cast iron and stainless steel.
· Mining. Major environmental impacts of mining. The most important impacts caused by mining activities are: – impacts on the atmosphere. – Impact on the water. – Impact on the ground. – Impacts on flora and fauna. – Impacts on the morphology and landscape. – Socio-cultural impacts on the environment.
Non-metallic mineral resources.
· Mineral used as fertilizer. Fertilizers are essential: phosphorus, nitrogen and potassium.
· Rocks used in construction. They are called acids and are derived from all known rock types. The most significant are:-stone blocks used by people as a refuge or to worship the dead or the gods since ancient times. – Rockery. Is any crushed rock used to build the road surfaces in the railroad and to make concrete. – Sand and gravel. Both types are extracted from the gravel pits, places to accumulate naturally. – Cement. A mixture of limestone and clay that is subjected to a firing temperature of over 1400º C so that it loses water and CO2 and then crushed. – Concrete. Dough made with a mixture of cement and sand or gravel. – Cast. The calcined gypsum rock is of the same name, so that it loses most of the water. – Clays. Clays have been used as building materials since ancient times. -glass. The glass is made by melting at 1700 º C on cheap and abundant raw materials, then cool rapidly.