Non-renewable energy sources are those that cannot be replenished within a human timescale. The 4 common non-renewable energy sources include coal, petroleum, natural gas, and nuclear energy.
Table of Contents
Introduction
Fossil fuels are natural energy sources formed from the remains of ancient plants and animals that have decomposed and been subjected to heat and pressure over millions of years. The main types of fossil fuels are coal, oil (petroleum), and natural gas.
They have been the primary sources of global energy for centuries. They provide power for industries, transportation, and households. However, their use leads to environmental pollution and depletion of natural reserves.
As the world shifts toward sustainable alternatives, the limitations of non-renewable energy sources are becoming increasingly apparent.
1. Coal
Coal is a fossil fuel formed from ancient plant material subjected to heat and pressure over millions of years.
It has been a dominant energy source, especially for electricity generation and industrial processes.
Impacts of Coal
Burning it releases significant amounts of carbon dioxide, and also sulphur dioxide, and nitrogen oxides. It also generates solid waste such as fly ash and slag, which require proper disposal. The gases it produces contribute to global warming, air pollution, and acid rain.
In other words, its mining has adverse effects on ecosystems and human health. Despite its negative environmental impacts, it remains widely used due to its abundance and cost-effectiveness.
Conversion of Coal into Usable Energy
Different methods are available to convert it into usable energy. These methods include:
Direct Combustion
Direct combustion is the most common method, where it is burned to produce steam that drives turbines.
Gasification
Gasification converts it into syngas. It is a fuel gas mixture primarily composed of CO, H₂, and CO₂. It is produced by gasifying carbon-containing materials, which can be used for electricity generation or fuel production.
Liquefaction
Transforming solid or gaseous fuels into liquid fuels is called liquefaction. This process converts it into liquid fuels, such as synthetic crude oil or diesel. For regions with limited oil supplies, this method is a better alternative.
Coal Reserves – Demand and Consumption
Its reserves are vast, with some estimates suggesting they could last for over a century. However, consumption rates are high, especially in developing nations.
Its demand is decreasing in some regions due to stricter environmental regulations and the rise of renewable energy.
Limitations
It has several limitations, for instance;
- It contributes to air pollution and greenhouse gas emissions.
- Mining practices can cause habitat destruction and water contamination.
- Fired power plants have lower efficiency compared to newer energy technologies.
2. Petroleum
It is a liquid fossil fuel and is also known as crude oil. It is formed from the remains of animals buried underground millions of years ago and is extracted through drilling.
It is a crucial energy source for transportation, electricity generation, and industrial applications.
Impacts of Petroleum
Oil refining produces various fuels such as petrol, diesel, and jet fuel, making it essential for modern economies.
However, the extraction and processing of oil contribute to environmental degradation and carbon emissions. Oil combustion releases pollutants such as carbon dioxide, carbon monoxide, and sulphur compounds.
Additionally, Oil spills and leaks also pose significant risks to marine and terrestrial ecosystems.
Conversion of Petroleum into Useable Energy
It is converted into useful products through several refining processes. The main methods include;
Refining
Crude oil is processed in oil refineries to separate and purify different hydrocarbons. The refining process includes multiple steps and produces fuels like petrol, diesel, jet fuel, and other petroleum-based products like asphalt and lubricants.
Fractional Distillation
Simply known as distillation, it is the primary refining process that separates crude oil into different components based on boiling points.
In this process, crude oil is heated and its components vaporise at different temperatures. The lighter fractions (e.g., petrol, propane) evaporate first and heavier fractions (e.g., diesel, lubricants) condense at higher temperatures.
Since this process creates separate fractions (that are further refined into useable fuels) that is why it is called fractional distillation.
Cracking
This process breaks down large, heavy hydrocarbons into smaller, more valuable hydrocarbons like petrol and diesel. There are two main types of cracking (thermal cracking and catalytic cracking) which are essential for increasing petrol production.
Additional Processes
There are other processes as well, such as reforming and hydrotreating. These processes ensure crude oil is converted into useful energy sources, powering transportation, industries, and homes worldwide.
Petroleum Reserves – Demand and Consumption
Its reserves are significant but unevenly distributed across the world. High consumption rates, particularly in transportation, make oil a critical commodity. However, geopolitical conflicts and market fluctuations affect its availability and price.
Limitations
Its limitations include;
- Its finite availability and contribution to climate change.
- Oil dependency can lead to economic instability due to price volatility.
- Reliance on it discourages the development of cleaner energy alternatives.
3. Natural Gas
It is a cleaner fossil fuel composed primarily of methane and formed from the remains of plants and animals.
It is used for electricity generation, heating, and industrial processes. It is favoured for its lower carbon emissions compared to coal and oil.
Impacts of Natural Gas
Extraction and transportation of it pose environmental and safety risks. Hydraulic fracturing (fracking) has been linked to groundwater contamination and seismic activity.
Waste produced from its combustion includes carbon dioxide and nitrogen oxides. Methane leaks from pipelines contribute significantly to greenhouse gas emissions. Reliance on it slows the adoption of renewable energy sources.
Conversion of Natural Gas into Usable Energy
It is converted into energy through several methods and each method serves a different purpose.
Combustion
This is the most common method for converting it into energy. In this process, gas is burned in power plants, industrial furnaces, and home heating systems to produce heat.
The heat produced in this process is used to generate steam that drives turbines to produce electricity. Also, it is used in internal combustion engines (e.g., gas-powered vehicles).
Combined Cycle Systems (CCS)
It is a highly efficient way of generating electricity from naturally occurring gas and works in two stages. This increases energy efficiency to over 60%, compared to traditional power plants (~35-40%).
The 1st stage is the “Gas Turbine Stage”, where gas is burned to spin a turbine. The 2nd stage is the “Steam Turbine Stage”, where waste heat from the gas turbine is used to create steam, which drives a second turbine.
Liquefaction
This process involved converting gas into Liquefied Natural Gas (LNG). It is achieved at a temperature of -162°C (-260°F). LNG is easier to transport and regasified for global trade.
It is used in international shipping, storage, and as a clean fuel for heavy-duty vehicles and ships.
Natural Gas Reserves – Demand and Consumption
Its reserves are substantial, but demand is rising due to its cleaner-burning properties. It is considered a transition fuel as the world moves toward renewable energy.
Limitations
The use of it is limited due to the following reasons;
- Methane leaks during extraction and transportation undermine its environmental benefits.
- Fracking, also called Hydraulic Fracturing, can cause water and air pollution.
- While cleaner than other sources, it still contributes to climate change.
4. Nuclear Energy
This energy is generated through the fission of uranium atoms in nuclear reactors. It provides a high-energy output with minimal greenhouse gas emissions.
Nuclear power plants supply electricity to millions of households and industries.
Impacts of Nuclear Energy
It raises concerns over nuclear accidents, radioactive waste, and high costs that affect its expansion. Besides these concerns, this energy remains a key player in reducing carbon emissions.
It produces radioactive waste that requires long-term management. Spent fuel rods and reactor components remain hazardous for thousands of years. Safe disposal and storage solutions, such as deep geological repositories, are critical challenges.
Conversion of Nuclear Energy into Usable Energy
It is converted through controlled fission reactions in reactors. The heat produced generates steam, which drives turbines to produce electricity. Advanced nuclear technologies aim to improve efficiency and safety.
Nuclear Energy Reserves – Demand and Consumption
Nuclear fuel has a high energy density, meaning small amounts can generate large amounts of power. Countries with developed nuclear infrastructure rely on it for energy demand. However, uranium is a finite resource, and nuclear plant construction is costly.
Limitations
Limitations include;
- It has high initial costs and long-term waste disposal issues.
- Public opposition and regulatory hurdles slow down new nuclear projects.
- Accidents, such as Chernobyl and Fukushima, have raised safety concerns.
Conclusion
Non-renewable energy sources have played a crucial role in the contemporary era. Globally, they are used in powering industries, transportation, and households.
However, these sources of energy have their cons as well, such as environmental degradation, depletion of resources, and associated risks. These issues highlight the need for sustainable alternatives to energy.
As the world transitions toward renewable energy, improving efficiency and minimising the negative effects of non-renewable sources remain essential for a balanced energy future.
Frequently Asked Questions (FAQs)
What are the 4 common non-renewable energy sources and their uses?
The most common non-renewable energy sources are coal, petroleum, natural gas, and nuclear energy. They are used for electricity generation, transportation, industrial processes, and heating.
How does coal contribute to air pollution and global warming?
Its combustion releases carbon dioxide, sulphur dioxide, and nitrogen oxides, contributing to air pollution, global warming, and acid rain.
What is the environmental impact of petroleum extraction and refining?
Its extraction can lead to habitat destruction and oil spills, while refining produces greenhouse gases and air pollutants such as carbon monoxide and sulphur compounds.
Why is natural gas considered a cleaner fossil fuel compared to coal and oil?
It burns more efficiently and produces fewer carbon emissions than other two, making it a relatively cleaner fossil fuel.
What are the main methods for converting coal into usable energy?
It is converted into energy through direct combustion, gasification, and liquefaction, which generate electricity, synthetic gas, and liquid fuels.
How does nuclear energy work, and what are its risks?
It is generated through the fission of uranium atoms, producing heat to generate electricity. Risks include radioactive waste, nuclear accidents, and high initial costs.
What are the major limitations of non-renewable energy sources?
Limitations include environmental pollution, resource depletion, greenhouse gas emissions, and dependency on finite reserves.
How does fractional distillation help refine crude oil into usable fuels?
Fractional distillation separates crude oil into different components based on boiling points, producing gasoline, diesel, jet fuel, and other petroleum products.
What are the long-term effects of using fossil fuels on climate change?
Fossil fuel use increases carbon dioxide levels, leading to global warming, rising sea levels, and extreme weather patterns.
Why is the world shifting towards renewable energy alternatives?
The world is transitioning to renewable energy to reduce carbon emissions, combat climate change, and ensure a sustainable energy future.