An analysis of emissions and carbon footprints for the various types of vehicle propulsion

Plans, predictions, and strategies to decrease emissions from vehicles are now being implemented as a direct result of anti-pollution legislation, which is currently in full swing. Countries that have achieved a high level of industrialization have enacted a variety of policies designed to encourage the production of clean (or less polluting) vehicles. These policies include the reduction of taxes as well as the imposition of penalties (such as green surcharges or even a ban on driving) on vehicles that emit high levels of pollutants that are in excess of what is considered to be acceptable levels. The public at large is coming around to the idea that human activity is responsible for the majority of climate change, as well as the emission of carbon dioxide and other greenhouse gases, and this theory has a solid foundation in the scientific community. The paper aims to explore findings in the context of the disproportionately carbon footprint for different means of transportation of goods.


Introduction
The carbon footprint, also known as the greenhouse gas footprint, is an indicator that may be used to compare the total quantity of greenhouse gases that are released by an activity, product, business, or nation [1].It is common practice to describe carbon footprints in terms of tons of emissions (CO2equivalent) per unit of comparison, such as per year, person, kilogram of protein, kilometer traveled, and other similar measures.
The total emissions produced by a product during its entire life cycle, from manufacture all the way through the supply chain to ultimate consumption and disposal, are included in the product's "carbon footprint."The direct and indirect emissions that an organization is responsible for are referred to as Scope 1, 2, and 3 in the Greenhouse Gas Protocol, which is used for the accounting of an organization's carbon footprint.In the same way, an organization's total carbon footprint comprises both of these types of emissions [2].
There are a number of approaches that may be taken and tools that can be used on the internet in order to calculate a person's carbon footprint; this number can also be determined for a nation, a company, a product, or an individual.If a customer wants to be more environmentally conscious about their consumption habits, for instance, considering a product's carbon footprint before making a purchase might be helpful.In the context of efforts that aim to mitigate the effects of climate change, the carbon footprint may be used to differentiate between economic activities that leave a large footprint and those that leave a small impact [3].To put it another way, the notion of carbon footprint makes it possible for anybody to draw comparisons between the climate-relevant effects that are caused by people, goods, corporations, and governments.When this is done, it is helpful in developing strategies and goals for minimizing the footprint left by carbon emissions.

Vehicle performances relative to carbon footprint
The carbon footprint is a representation of the emissions that are associated with a certain activity, such as the generation of electricity, transportation, the cooling of space, the construction of structures, the manufacturing of industrial goods, or agricultural goods [4].The practice of lowering, eliminating, or preventing emissions of greenhouse gases is referred to as carbon offsetting.Carbon offsetting is quantified in CO2-eq equivalent.The CO2-eq is a unit that is used to compare the radiative power of a greenhouse gas (GHG) with the radiative force of carbon dioxide.
The mass of that chemical multiplied by its global warming potential (GWP) will be used in the calculation to determine the carbon dioxide equivalent of that substance.For instance, the global warming potential of methane is 23, but the GWP of nitrous oxide is 296.Carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases are the most significant contributors to global warming.The quantities of greenhouse gases (GHGs) in the atmosphere are already there naturally, but human actions like the combustion of fossil fuels are increasing those levels, which leads to climate change.
Emissions of greenhouse gases are often measured in terms of CO2-equivalents, which is a measurement metric that is used to compare different types of gases that have an effect on the atmosphere with regard to their potential to contribute to global warming in comparison to CO2's contribution [4,5].In general, the total CO2 equivalent emissions made by a vehicle over the course of its lifetime may be calculated as: where:   , ,  , ,  , are the emission for production, use and recycling Even before a vehicle can be used to carry products or people, a significant quantity of greenhouse gas must be generated so that the raw materials can be extracted and the vehicle can be manufactured [6].Estimates of the total CO2 equivalent that is produced as a result of the manufacturing of a vehicle,  , , may still be derived from the following sources [5]: where:    is the nominal battery capacity measured in kWh    is the specific energy measured in kWh/kg.The total equivalent of emissions [5,6] using  , CO2 may still be calculated as follows: , =   ×   ×   (4) where:    is the relative energy/fuel consumption based on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP)    is the expected lifetime of the vehicle in km Even if the emissions related with the manufacturing of spare parts and the maintenance of vehicles are ignored (which is inconsequential in the grand scheme of things), the total equivalent of emissions can still be determined [5,7]. relative emissions can be separated according to the following formula: This is because WTT emissions typically take into account the extraction processes of the energy source, the production of energy carriers, and the distribution of energy carriers, whereas TTW emissions only take into consideration the energy conversion process required to actually propel the vehicle [8].There is a clear correlation between the exhaust gases released by traditional ICEVs and the pollutants they produce [5,10].Consequently, the relative   2 equivalent emissions of ICEVs may be estimated easily using the following formula: (6) where:    2  is the total CO2 emissions assessed    is the WLTP mileage In contrast, assessing the emissions produced by PHEVs is more challenging due to the fact that PHEVs may be driven by both an electric motor and an internal combustion engine.Electric motors do not produce any local CO2 emissions [10,11].It is required to apply a utility factor (UF), which is defined as the ratio of the distance traveled when the battery charge was reduced to the total distance of the WLTP [4,5,6].The quantity of total CO2 emissions may be computed as follows: where:    2  is the CO2 emissions associated with the 'charge depletion' mode    2  is the CO2 emissions associated with the 'charge support' mode.
When compared, the CO2 emissions produced by BEVs and FCEVs while being driven are considered to be zero.This is due to the fact that these vehicles do not produce CO2 in the immediate environment.However, their use of fuel or energy is something that has to be monitored.With this in mind it is also possible to determine the total CO2 equivalent of recycling emissions using the following formula [5,10,12]: where:   , are the total CO2 recycling emissions

WTW emissions evaluation for hybrid vehicle
The evaluation for the hybrid vehicle with regards to WTW emissions was done in the software platform GREET, which stands for "Greenhouse gases, regulated emissions, and energy use in transport".This is a platform that analyzes the implications that vehicle technology, fuels, energy products, and energy systems have across their entire lifecycles.It offers a transparent platform that producers of energy and vehicle systems, researchers, and regulators may use to evaluate the energy and environmental consequences of the technology and products that are used in car and energy system systems.With the help of the application, we were able to determine overall energy consumption (including non-renewable and renewable forms), air pollutant emissions, greenhouse gas emissions, and water consumption for any energy system or vehicle.

Conclusion
When compared to conventional cars powered by internal combustion engines, electric vehicles have a number of benefits over their more traditional counterparts, including higher powertrain efficiency, lower maintenance needs, and zero emissions from the exhaust.These factors all contribute to a reduction in urban air pollution.Nevertheless, in contrast to their effects on the environment, reality is more complicated, necessitating a more comprehensive accounting of the consequences that are documented throughout the vehicle's life cycle.Switching away from electric cars results in large overall savings in CO2 emissions when a major portion of the power is produced from sources that do not produce carbon.In contrast, nations in which a significant amount of power is produced by the burning of coal may find that switching to electric cars results in an increase in the total CO2 emissions related with transportation.
It is important to highlight that when switching to renewable sources for the generation of electricity, considerable cuts may be made in the quantities of pollutants and greenhouse gases produced across all of the categories that were taken into consideration in the WTW study above.In the worst-case scenario, when there is a production rate of 50% coal, total CO2 emissions reach 190g/km traveled.However, if a portion of this proportion migrates to natural gas, which has lower greenhouse gas emissions, gains may be seen.While Mix 4 based primarily on natural gas and nuclear power but with low values for hydropower and wind shows similar results to the current situation, Mixes 5 and 6, where the percentage of nuclear, hydro, and wind energy constitute 3 quarters of production sources, reduce carbon emissions by a third in comparison to the worst case scenario.Mix 5 is based primarily on natural gas and nuclear power while Mix 6 is based primarily on wind and hydropower.
and   , are the weight of the vehicle measured in kilograms and battery capacity measured in kilowatt-hours (only for electric vehicle types)   , and  , are the relative CO2 equivalents of the vehicle body and battery and are represented in kilograms of CO2 equivalents per kilogram and kilograms of CO2 equivalents per kilowatt-hour.The total weight of the vehicle, denoted by  ℎ , may be broken down into the vehicle's body mass, denoted by  ℎ, , and its battery mass, denoted by  ℎ,[5,6,7], based on the following formula: ℎ =  ℎ, +  ℎ, =  ℎ, +    (3) where:

Figure 1 .
Figure 1.The methodical approach for devising new instances.

Figure 2 .
Figure 2. Partial results for the energy consumption.