What are the various ways in which energy is consumed in the world?

Population growth has a direct relation to the growing energy demand of mankind. A major emphasis has been laid on the usage of various energy supplies from both renewable and nonrenewable energy sources to meet the global energy demand. The energy supply from burning renewable energy sources such as bioenergy, hydropower, and natural gas has accounted for clean release of the by-products and zero carbon emissions. On the other hand, large-scale energy supply from the combustion of fossil fuels forms the global energy system. Fossil fuels fulfill two-thirds of the world's energy consumption.

According to a report by International Energy Agency (IEA), the annual energy demand for the USA was 93 quadrillion British thermal units, BTU for the year 2020, which is expected to get doubled shortly soon. Moreover IEA concluded that the global energy demand is promised to increase by 4.6% in 2021. This global energy demand will boost carbon dioxide emissions by 5% along with carbon monoxide and nitrogen oxide emissions. Fatih Birol, the current executive director of IEA, warned various coal-fired power plants, the sole contributors of these dangerous figures.

This article provides an in-depth insight into the various energy-related sources along with the fundamentals about how these energy sources impact the environment.

Energy demand and energy consumption

The term energy directly points towards electrical energy consumption. In South Asia, India is the seventh-largest country in the world with the world's largest democracy. As per IEA, India is the world's fourth-largest energy consumption country followed by China, the USA, European Union, and the Sub-Saharan.

Fossil fuels are the primary energy sources of the USA. 35% of the nation's energy is met from petroleum, 34% from natural gas, and 10% from coal.

Global energy consumption is primarily based on oil, coal, natural gas, fossil fuels, hydropower, wind, solar, and other renewables. About 20,000 TWh of energy consumption comes from burning coal, followed by 80,000 TWh from oil-based energy sources such as petroleum; whereas 120,000 to 160,000 TWh from other energy sources such as renewable energy sources, natural gases, and other sources. These figures signify that the global energy system of the world has made a major turnover from conventional energy sources to renewable energy sources. A majority of investments come from the world bank regarding power plant installations.

Different types of energy sources

Electricity is generated in power plants. A power plant is a unit that relies on both conventional and non-conventional energy sources for electricity generation. A power plant incorporates various components and equipment such as turbines and generators that play a significant role in the energy conversion, from the energy input to the electrical energy output.

Here, in this section, the different energy sources which are the prime input to a power plant are outlined.

Conventional energy sources

Conventional energy sources are those energy sources that are primarily derived from organic substances buried deep inside the earth's surface. They are the dead remains of plants and animals formed over time due to the application of high heat and temperature.

A major characteristic of a conventional energy source is that it is exhaustible upon time and usage. Some of the most common conventional energy sources are petroleum and coal. Coal occurs in between the layers of sedimentary rocks, whose heat energy is used by the thermal power plants for generating energy. The thermal power plants have large furnaces installed that take input of fuel like coal to produce heat energy. The energy is transferred to large boilers that create high-pressure steam which forms the basic input for the steam turbines. The steam turbines have a series of blades mounted around the periphery of the turbine shaft which converts the pressure energy into mechanical energy. A coupled generator with the turbine shaft is responsible for electricity generation.

Petroleum serves as the second most important energy source after coal. Petroleum itself is a thick liquid with high viscosity and plays no role in energy production. To make petroleum usable, it has to undergo a refining process known as fractional distillation. The products of which are petrol, diesel, and petroleum gas. Power plants, that rely on petroleum products, have large internal combustion (IC) engines in place of turbines, these IC engines are coupled to an AC generator that produces electricity.

Non-conventional energy sources

Non-conventional energy sources are those energy sources that are found naturally and are abundant in nature. These energy sources never get exhausted and account for clean energy production. These energy sources contribute to zero greenhouse gas emissions and other harmful compounds that directly or indirectly impact the environment. The world has seen a major shift from conventional energy sources to non-conventional sources with the rise in population growth and energy demand.

Solar energy, wind energy, tidal energy, geothermal energy, hydropower energy, and biomass energy are some examples of non-conventional sources.

Effect on environment

Various environmental effects are caused due to the burning of conventional energy sources, some of which are outlined below.

Global warming

The extensive use of coal and petroleum has led to the rise of global warming. These fuels have carbon as their primary constituent. Upon burning, they release carbon dioxide and other harmful substances into the atmosphere. Carbon dioxide is the primary greenhouse gas that is responsible for global warming. There is a deliberate switch towards the use of low-carbon energy usage known as decarbonization. It helps to remove or reduce the carbon dioxide (CO₂) output into the atmosphere.

Acid rain

Sulfur dioxide and nitrogen oxide are the two compounds responsible for acid rain. These compounds are extensively released from automobile exhausts and through the chimneys of various power plants. These compounds when mixed with water and oxygen in the atmosphere, form nitric acid and sulfuric acid, which are two of the most corrosive acids known to humankind. These toxins are brought down by rain that damage the environment.

Context and Applications

The topic is extensively taught in various undergraduate and postgraduate degree courses like-

• Bachelor of Technology (Civil engineering)
• Master of Technology (Civil engineering)
• Bachelor of Technology (Mechanical engineering)
• Master of Technology (Mechanical engineering)

Practice problems

Q 1. By which of the following methods does petroleum refine?

1. Decarbonization
2. Fractional distillation
3. Fractional decarbonization
4. None of these

Answer: Option b

Explanation: Petroleum is refined through fractional distillation. The process of fractional distillation is performed in long columns known as fractional distillation columns. Inside the fractional distillation column, petroleum (crude oil) is heated and its vapors are allowed to cool at different condensation temperatures. 

Q 2. Which of the following organization is responsible for measuring energy consumption worldwide?

1. World bank
2. International Energy Agency (IEA)
3. World energy agency
4. World energy policymaker

Answer: Option b

Explanation: International Energy Agency (IEA) is responsible for measuring and providing a statistical insight into world energy consumption. It is an autonomous intergovernmental organization, it provides detailed analysis, data, recommendations, and solutions to countries for judicious use of sustainable or renewable energy. 

Q 3. Which of the following is a conventional energy source?

1. Petroleum
2. Solar energy
3. Hydropower energy
4. Tidal energy

Answer: Option a

Explanation: Petroleum is an example of a conventional energy source. Conventional energy sources are those sources that are not present in ample amounts in the earth's crust. Overuse of these resources will lead to extinction in the near future.

Q 4. Which of the following is a non-conventional energy source?

1. Hydro power
2. Fossil fuel
3. Solar energy
4. Both a and c

Answer: Option d

Explanation: Both hydropower and solar energy are examples of non-conventional energy sources. As these sources are also called renewable energy sources, these energy sources can be replenished by the nature upon their usage. Hydropower energy is achieved by flowing water whereas solar energy is acquired from the sun.  

Q 5. Which of the following is the primary greenhouse gas?

1. Carbon dioxide
2. Carbon monoxide
3. Sulfur dioxide
4. All of these

Answer: Option a

Explanation: Carbon dioxide is the primary greenhouse gas. carbon dioxide is the major gas produced by burring conventional energy sources. Greenhouse gas leads to ozone layer depletion and it is a primary factor for global warming.