Non-Renewable Energy Sources and Environmental Impact

Energy Density of Non-Renewable Resources

• Wood: 14,000 kJ/kg
• Coal: 30,000 kJ/kg
• Oil: 40,000 kJ/kg
• Natural gas: 1 m³ equals 0.9 kg of oil
• Uranium: 1 g is equivalent to 1.7 metric tons of oil
• Deuterium: 1 g is equivalent to 7.4 metric tons of oil

Natural Gas and Nuclear Energy

Natural gas: A mixture of methane and other hydrocarbons. It has high power and low-polluting energy, generating CO₂ and water. Spain has significantly increased its use.

Nuclear energy: The energy source is uranium-235, used in nuclear fission reactors. It can also be fueled by plutonium, an element that is derived from uranium. Natural uranium cannot be used directly as fuel because it has a very small proportion of uranium-235; therefore, it must be enriched until it is at least 3% enriched uranium-235. Nuclear fusion provides more energy than nuclear fission for the same mass of fuel. The generation by fusion of one gram of helium from deuterium provides more than 3.1 × 10¹¹ J. However, it requires temperatures of millions of degrees to fuse atomic nuclei, which are difficult to achieve under controlled conditions. Currently, there are still no fusion power plants.

Air Pollution: Causes and Effects

Air pollution is the presence of gaseous, liquid, or solid substances in the air that are harmful to humans, other living beings, and the environment. It is also often considered to include the presence of radiation and noise in the air.

Sources of Atmospheric Pollutants

The contaminants may be natural (such as volcanoes) or artificial, resulting from human activity. The burning of fossil fuels releases polluting gases into the atmosphere:

1. Sulfur dioxide and nitrogen: Causes eye irritation, respiratory system disorders, retarded plant growth, and corrosion of metals; it also contributes to acid rain.
2. Carbon monoxide: Highly toxic and can produce death in high concentrations.
3. Carbon dioxide: Contributes significantly to the greenhouse effect.

Acid Rain and the Greenhouse Effect

Acid rain: Sulfur oxides react with water vapor in the upper atmosphere to produce sulfuric acid. Similarly, nitrogen oxides produce nitric acid. Acid rain alters plant growth, increases the acidity of soil and water, dissolves toxic metals, and leads to the deterioration of monuments (stone disease).

The Greenhouse Effect: Life on Earth depends on the energy it receives from the Sun in a delicate balance. Almost one-third of this energy is returned directly to outer space because it is reflected by the atmosphere, clouds, dust in suspension, and the Earth's surface. Another part of the received energy is absorbed by the oceans and continents and then radiated back to space. A small fraction of this energy is absorbed by greenhouse gases (GHG) in the atmosphere, primarily carbon dioxide and methane. The balance between absorbed and radiated energy keeps the planet's temperature at approximately 15 °C. If the GHG concentration increases, the balance is upset, causing global warming, which can lead to increased precipitation in humid areas and increasing aridity in dry areas.