Question

If carbon dioxide emission is a chief concern, switching from a coal-fired electricity plant to natural gas input is still a use of fossil fuels, but natural gas produces less \(\mathrm{CO}_{2}\) per energy unit than coal (Table 9.1). By what factor would \(\mathrm{CO}_{2}\) emissions be reduced if replacing all energy \(^{76}\) we now get from coal with energy from natural gas?

Short answer

Answer: To find the factor by which CO2 emissions would be reduced, follow these steps: 1) Find the CO2 emissions per energy unit for both coal and natural gas from Table 9.1. 2) Calculate the ratio of CO2 emissions for natural gas to coal by dividing the CO2 emissions per energy unit of natural gas by the CO2 emissions per energy unit of coal. The resulting "Reduction Factor" represents the factor by which CO2 emissions would be reduced after the switch.

Step-by-step solution

Find CO2 Emissions per Unit Energy for Coal and Natural Gas

Refer to Table 9.1 and look for the values of CO2 emissions per energy unit of both coal and natural gas. Let's say the values are \(COAL_{CO2}\) for coal, and \(NG_{CO2}\) for natural gas. Be sure to use the same unit of energy in both cases.

Calculate the Ratio of CO2 Emissions for Natural Gas to Coal

To find the factor by which CO2 emissions would be reduced if replacing all energy from coal with energy from natural gas, we need to calculate the ratio of their emissions per energy unit. To do this, divide the CO2 emissions per energy unit of natural gas by the CO2 emissions per energy unit of coal: \[\text{Reduction Factor} = \frac{NG_{CO2}}{COAL_{CO2}}\]

Interpret the Result

The resulting number, which we will call the "Reduction Factor," represents the factor by which CO2 emissions would be reduced if all energy production from coal were replaced by natural gas. If the Reduction Factor is greater than 1, this means that natural gas produces less CO2 emissions per energy unit than coal and switching to natural gas would indeed reduce CO2 emission. If the Reduction Factor is less than 1, this means natural gas produces more CO2 emissions per energy unit than coal, and switching to natural gas would not be beneficial for CO2 emission reduction.

Key concepts

Fossil Fuels Impact

Fossil fuels, including coal, oil, and natural gas, have been the backbone of industrialization and energy production for over a century. Combustion of these fuels releases a multitude of pollutants and greenhouse gases, notably carbon dioxide (CO2), into the atmosphere.
The extensive use of fossil fuels is the predominant source of anthropogenic CO2 emissions, contributing to the increasing concentration of these gases in Earth's atmosphere. Elevated CO2 levels are a significant contributor to the greenhouse effect, leading to global climate change. The impact of fossil fuels on the environment underscores the urgency for more sustainable energy sources and technologies to mitigate negative effects such as air and water pollution, habitat destruction, and health risks associated with poor air quality.
In our exercise, the shift from a high carbon-intensive fuel like coal to a comparatively cleaner alternative such as natural gas shows an effort to reduce the repercussions of fossil fuel combustion. Although not a perfect solution, understanding the emissions per unit of energy of different fuels enables us to make more informed decisions about our energy consumption patterns and the subsequent environmental footprint.

Energy Production

Energy production is a critical aspect of modern society, essential for everything from household electricity to industrial processes. It is primarily sourced from fossil fuels due to their high energy content and relative ease of extraction and use. However, the types of fossil fuels used can vary in terms of carbon intensity, or the amount of CO2 produced per unit of energy.
Coal, being the least efficient of the fossil fuels in terms of energy content per volume, also leads to higher CO2 emissions compared to natural gas. During combustion, natural gas generates less CO2 per unit of energy, making it a 'cleaner' fossil fuel option. Nevertheless, it's essential to note that transitioning to natural gas is an interim measure, as the ultimate goal is to adopt renewable energy sources, such as wind, solar, and hydroelectric power, which produce energy without CO2 emissions.
The exercise we're discussing proposes such a transition, highlighting that even within the realm of fossil fuels, choices can be made to reduce the environmental impact. The calculation of the Reduction Factor shows the extent to which emissions can be curtailed by switching from coal to natural gas for energy production.

Environmental Science

Environmental science explores the interactions between the physical, chemical, and biological components of the environment, including the investigation of how human activities affect our planet. It plays a vital role in understanding and addressing issues such as climate change, pollution, and conservation.
In the context of CO2 emissions, environmental science provides insight into the carbon cycle, the consequences of altering it through emissions, and the steps we can take to mitigate damage. It employs scientific methods to calculate, analyze, and predict the environmental impact of energy choices, as seen in our textbook exercise.
Reducing our carbon footprint through informed decisions is a fundamental principle in environmental science. The calculated Reduction Factor enables us to quantify the benefit of switching from coal to natural gas and contributes to a broader understanding of environmental management. This knowledge can guide policy-making, technological innovation, and personal choices towards sustainability, encapsulating the goals of environmental science.