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Emission intensity Wiki2Web Clarity Challenge

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Study Guide: Carbon Intensity and Emission Factors: Methodologies and Applications

Cheat Sheet:
Carbon Intensity and Emission Factors: Methodologies and Applications Study Guide

Fundamental Concepts and Definitions of Emission Intensity

An emission intensity quantifies the rate of pollutant emission in relation to the intensity of an activity or industrial process.

Answer: True

Explanation: Emission intensity is defined as the rate at which a specific pollutant is emitted relative to the intensity of a particular activity or industrial production process, serving to quantify environmental impact per unit of output.

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Carbon intensity per kilowatt-hour (CIPK) is a measure used to compare emissions from various sources of electrical power.

Answer: True

Explanation: CIPK quantifies the amount of carbon emitted for each unit of electricity produced, enabling direct comparison of different energy generation methods.

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Emission intensities are primarily used to estimate air pollutant or greenhouse gas emissions based on activity data.

Answer: True

Explanation: Emission intensities are a key tool for estimating air pollutant and greenhouse gas emissions by correlating them with specific activity data.

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The carbon intensity of electricity directly measures the quantity of greenhouse gases emitted for each unit of electricity produced.

Answer: True

Explanation: The carbon intensity of electricity quantifies the greenhouse gases emitted per unit of electricity generated, typically in grams of CO2 equivalents per kilowatt-hour.

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What is the fundamental definition of an emission intensity?

Answer: The rate at which a specific pollutant is emitted in relation to the intensity of a particular activity or an industrial production process.

Explanation: Emission intensity quantifies the rate of pollutant emission relative to the intensity of an activity or industrial process, providing a metric for environmental impact per unit of output.

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Which of the following is NOT an example of how emission intensity is typically measured?

Answer: The total number of industrial facilities in a region.

Explanation: Emission intensity is measured in relation to activity or economic output, such as g CO2/MJ or GHG emissions/GDP, not simply by counting facilities.

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What is the primary application of emission intensities in projecting future climate scenarios?

Answer: To analyze the interrelations of population, economic activity, and energy technologies using the Kaya identity.

Explanation: Emission intensities are used in projecting future climate scenarios, often analyzed with the Kaya identity to understand the interrelations of population, economic activity, and energy technologies.

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What is the meaning of 'carbon intensity per kilowatt-hour' (CIPK)?

Answer: The amount of carbon emitted for each unit of electricity produced.

Explanation: CIPK quantifies the carbon emitted per unit of electricity produced, allowing for direct comparison of different energy generation methods.

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Emission Assessment Methodologies (LCA, WTW)

The Well-to-Wheels (WTW) methodology is a more comprehensive approach than a full Life-Cycle Assessment (LCA) because it includes end-of-life emissions for all machinery.

Answer: False

Explanation: The Well-to-Wheels (WTW) methodology is a simplified version of LCA, specifically excluding emissions related to the manufacturing and end-of-life of plants and machinery, making it less comprehensive than a full LCA.

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The simplest methodology for assessing carbon intensity includes upstream emissions but excludes direct process emissions.

Answer: False

Explanation: The simplest methodology for assessing carbon intensity only considers direct emissions from a specific process and typically excludes upstream emissions.

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The GREET model in the US and JEC WTW analyses in Europe commonly employ the Well-to-Wheels (WTW) methodology.

Answer: True

Explanation: The GREET model in the United States and the JEC WTW analyses in Europe are prominent examples of models that utilize the Well-to-Wheels (WTW) methodology to evaluate the environmental impact of fuels and vehicles.

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The Whole Life-Cycle Assessment (LCA) methodology is considered simple due to the limited number of variables it requires.

Answer: False

Explanation: The Whole Life-Cycle Assessment (LCA) methodology is a comprehensive and complex approach, requiring a large set of variables, and is therefore not considered simple.

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What does the Well-to-Wheels (WTW) methodology specifically exclude that a full Life-Cycle Assessment (LCA) includes?

Answer: Emissions related to the manufacturing and end-of-life of plants and machinery.

Explanation: The WTW methodology excludes emissions from the manufacturing and end-of-life stages of plants and machinery, which are included in a full LCA.

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Which model commonly uses the Well-to-Wheels (WTW) methodology in the United States?

Answer: The GREET model.

Explanation: In the United States, the GREET model is a primary adopter of the Well-to-Wheels (WTW) methodology for assessing environmental impact.

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Which methodology is a simplified version of LCA, commonly applied in the energy and transport sectors?

Answer: Well-to-Wheels (WTW) methodology.

Explanation: The Well-to-Wheels (WTW) methodology is a simplified LCA variant frequently used in the energy and transport sectors.

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Emission Factors and Measurement Units

According to the IPCC's 2011 review, coal had the lowest 50th percentile life-cycle greenhouse gas emissions among all electricity sources listed.

Answer: False

Explanation: The IPCC's 2011 review indicated that coal (various generator types without scrubbing) had the highest 50th percentile life-cycle greenhouse gas emissions at 1001 g CO2-eq/kWh_e, not the lowest.

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The carbon intensity of electricity is typically expressed in grams of CO2 equivalents per megajoule of electricity.

Answer: False

Explanation: The carbon intensity of electricity is typically expressed in grams of CO2 equivalents per kilowatt-hour of electricity, not per megajoule.

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Carbon dioxide (CO2) and sulfur dioxide (SO2) emissions from fuel combustion can be estimated with high certainty due to their dependence on fuel content and complete oxidation.

Answer: True

Explanation: CO2 and SO2 emissions are highly certain because they depend almost exclusively on the fuel's precisely known carbon and sulfur content, and these elements are almost completely oxidized during combustion.

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Nitrous oxide (N2O) emissions from agricultural soils are highly certain because they are primarily influenced by the type of fertilizer used.

Answer: False

Explanation: Nitrous oxide (N2O) emissions from agricultural soils are highly uncertain, influenced by soil conditions, fertilizer application, and meteorological conditions, not solely by fertilizer type.

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The conversion factor between grams per megajoule (g/MJ) and grams per kilowatt-hour (g/kWh) is 1 g/MJ = 3.6 g/kWh.

Answer: True

Explanation: The conversion factor is based on the equivalence that 3.6 MJ equals 1 kWh, thus 1 g/MJ is equivalent to 3.6 g/kWh.

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What was the 50th percentile CO2 emission value for hydroelectric power from reservoirs, according to the IPCC's 2011 review?

Answer: 4 grams of CO2 equivalents per kilowatt-hour of electricity.

Explanation: The IPCC's 2011 review found the 50th percentile CO2 emission value for hydroelectric power from reservoirs to be 4 g CO2-eq/kWh_e.

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Which electricity source had the highest 50th percentile life-cycle greenhouse gas emissions according to the IPCC 2011 review?

Answer: Coal (various generator types without scrubbing).

Explanation: The IPCC's 2011 review identified coal (various generator types without scrubbing) as having the highest 50th percentile life-cycle greenhouse gas emissions at 1001 g CO2-eq/kWh_e.

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What is the thermal emission factor for wood?

Answer: 115 g(CO2e)/MJth.

Explanation: The thermal emission factor for wood is 115 grams of CO2 equivalents per megajoule thermal (g CO2e/MJth).

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What is the electric emission factor for natural gas combined cycle generation?

Answer: 577 g(CO2)/kWh_e.

Explanation: For natural gas combined cycle generation, the electric emission factor is 577 g CO2/kWh_e.

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What conversion factor allows for easy conversion between grams per megajoule (g/MJ) and grams per kilowatt-hour (g/kWh)?

Answer: 1 g/MJ = 3.6 g/kWh.

Explanation: The conversion factor is based on the equivalence that 1 g/MJ is equivalent to 3.6 g/kWh, derived from 3.6 MJ = 1 kWh.

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Why are estimates for non-CO2 greenhouse gases from combustion generally less certain than CO2 emissions?

Answer: Their emission levels depend on specific combustion technology, incomplete combustion, or complex chemical processes.

Explanation: Non-CO2 greenhouse gas emissions are less certain due to their dependence on specific combustion technology, incomplete combustion, or complex chemical and physical processes.

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What does the abbreviation 'W_L' signify in the context of emission factors for fuels?

Answer: Light Water Reactors.

Explanation: In the context of fuel emission factors, 'W_L' is the abbreviation for Light Water Reactors.

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What is the formula used to estimate emissions based on activity and emission factors?

Answer: Emission_pollutant = Activity * Emission Factor_pollutant.

Explanation: The formula Emission_pollutant = Activity × Emission Factor_pollutant is used, assuming a direct proportionality between activity and pollutant emission.

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Fuel-Specific Carbon Intensities

Coal has a high CO2 emission intensity because it is primarily composed of hydrogen.

Answer: False

Explanation: Coal has a high CO2 emission intensity primarily because it is composed mostly of carbon, which produces a large amount of CO2 upon combustion.

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Natural gas has a medium CO2 emission intensity compared to coal because its combustion produces water vapor in addition to CO2.

Answer: True

Explanation: Natural gas, primarily methane (CH4), has a medium CO2 emission intensity compared to coal because its hydrogen content produces water vapor upon combustion, resulting in lower CO2 emissions per unit of energy.

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The 2018 Science article by Masnadi et al. focused on modeling the well-to-refinery carbon intensity of all major active oil fields globally.

Answer: True

Explanation: The 2018 Science article by Masnadi et al. aimed to model the well-to-refinery carbon intensity of all major active oil fields worldwide and identify the primary drivers of these emissions.

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According to a Stanford University study, Canadian crude oil was identified as the most greenhouse gas intensive in the world.

Answer: False

Explanation: The Stanford University study identified Canadian crude oil as the fourth-most greenhouse gas intensive globally, following Algeria, Venezuela, and Cameroon, not the most intensive.

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Approximately 90% of Chinese oil fields emitted between 1.5 and 13.5 grams of CO2 equivalents per megajoule.

Answer: True

Explanation: Observations of Chinese oil fields indicated that approximately 90% of them emitted within the range of 1.5–13.5 g CO2e per megajoule.

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Why does coal possess a high CO2 emission intensity?

Answer: It is composed mostly of carbon.

Explanation: Coal's high CO2 emission intensity stems from its primary composition of carbon, which converts to a large amount of CO2 upon combustion.

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According to the Stanford University study published in Science, which country's crude oil was identified as the fourth-most greenhouse gas intensive in the world?

Answer: Canada.

Explanation: The Stanford University study identified Canadian crude oil as the fourth-most greenhouse gas intensive globally.

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What is the primary reason natural gas has a medium CO2 emission intensity compared to coal?

Answer: It contains four hydrogen atoms to burn for each carbon atom, producing water vapor.

Explanation: Natural gas, primarily methane, produces water vapor from its hydrogen content during combustion, leading to lower CO2 emissions per unit of energy compared to coal.

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What was the objective of the 2018 Science article by Masnadi et al. concerning oil fields?

Answer: To model the well-to-refinery carbon intensity of all major active oil fields globally.

Explanation: The 2018 Science article by Masnadi et al. aimed to model the well-to-refinery carbon intensity of major active oil fields worldwide and identify emission drivers.

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What was the observed range of CO2e emissions per megajoule for Chinese oil fields?

Answer: Between 1.5 and more than 40 g CO2e/MJ.

Explanation: Chinese oil fields exhibited a CO2e emission range of 1.5 to over 40 g CO2e/MJ, with most fields falling within 1.5–13.5 g CO2e.

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Climate Policy, Reporting, and Mitigation Strategies

The Commodity Exchange Bratislava (CEB) calculated the carbon intensity for Voluntary Emissions Reduction projects in 2012 to be 0.343 metric tons per megawatt-hour.

Answer: True

Explanation: In 2012, the CEB indeed calculated the carbon intensity for Voluntary Emissions Reduction projects as 0.343 metric tons per megawatt-hour.

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To achieve its 2030 greenhouse gas emission reduction goal, the EU needs to invest approximately €100 billion annually in energy efficiency.

Answer: False

Explanation: The EU needs to invest approximately €300 billion annually in energy efficiency, as part of a total annual energy investment exceeding €400 billion, to achieve its 2030 greenhouse gas emission reduction goal.

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The United Nations Framework Convention on Climate Change (UNFCCC) requires Annex I Parties to report national greenhouse gas inventories annually.

Answer: True

Explanation: The UNFCCC mandates that Annex I Parties annually report their national total greenhouse gas emissions in a formalized inventory format.

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The UNFCCC accepts the 2006 IPCC Guidelines as the standard estimation methods for national greenhouse gas inventories.

Answer: True

Explanation: The UNFCCC has accepted the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories as the standard estimation methods, ensuring consistency and accuracy.

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It is considered 'good practice' to develop country-specific emission factors only for minor sources of emissions.

Answer: False

Explanation: According to the IPCC, it is considered 'good practice' to develop country-specific emission factors for activities that represent a major source of emissions, often referred to as a 'key source,' not for minor sources.

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According to a 2024 report, what percentage of the energy mix did renewable energy production reach?

Answer: 50%.

Explanation: A 2024 report indicated that renewable energy production achieved 50% of the total energy mix.

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Which international body requires Annex I Parties to annually report their national total emissions in a formalized format?

Answer: The United Nations Framework Convention on Climate Change (UNFCCC).

Explanation: The UNFCCC mandates annual reporting of national greenhouse gas inventories by Annex I Parties in a formalized format.

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What is the EU's goal for decreasing greenhouse gas emissions by 2030 compared to 1990 levels?

Answer: At least 55%.

Explanation: The EU aims to decrease greenhouse gas emissions by at least 55% by 2030 compared to 1990 levels.

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Where can commercially applicable organizational greenhouse gas emission factors be found?

Answer: On EmissionFactors.com.

Explanation: Commercially applicable organizational greenhouse gas emission factors are available on EmissionFactors.com, in addition to IPCC guidelines and databases.

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