-This lesson on LCA and well-to-wheel analysis will be split over two videos. This first video is divided in 2 parts. The first part will introduce the well-to-wheel analysis, its principle and associated definitions. The second part will introduce the different sectors for passenger cars, conventional and alternative sectors. Passenger cars have several impacts on the environment. Materials and energy are required to manufacture them. They need fuel to run. Finally, they release greenhouse gas emissions in the atmosphere such as carbon dioxide or CO2, but also particle or other pollutant emissions. When a car reaches the end of its life, part of the car components can get back in the loop thanks to recycling. But another part cannot be recycled and must be disposed of. If we look at the different steps of a car life cycle, we can calculate the environmental impacts of each of these steps. This calculation and analysis of environmental impacts in each step of a product's life cycle in general, and in particular for a car, is called life-cycle analysis, LCA. The life-cycle analysis can be simplified by only looking at two steps for a passenger car. First, the step related to fuel or energy source production that will be used by the car. This first step is called the "well-to-tank" step or WTT. The second step is related to the use of the car and is called the "tank-to-wheel" step or TTW. This analysis is called the "well-to-wheel" analysis. It is a simplified analysis of the life cycle since it only considers two steps of the life cycle instead of all the steps. Then, we only look at two environmental indicators: the primary fossil energy consumption in mega joule of fossil energy per traveled kilometers made with the car, and the greenhouse gas emissions in CO2 equivalent grams per kilometer. CO2 equivalent grams are calculated based on all the greenhouse gas emissions that are multplied by an equivalent factor that transforms them into C02 emissions. In order to calculate these two environmental indicators, the energy consumption and the greenhouse gas emissions, we need to look at how much mega joule of fossil energy is consumed per mega joule of fuel used in the tank and how much CO2 equivalent grams are emitted per mega joule of fuel produced. For instance, in the case of petrol, we need to quantify these two indicators, energy and emissions, for each step from the production until petrol distribution. Then, for the tank-to-wheel step, we need to look at fossil energy consumption and greenhouse gas emissions associated with the use of the car. To do this, we can use what we call standardized cycles. The car is tested on a chassis dynanometer that enables us to measure CO2 emissions and energy consumption. This chassis dynanometer enables the car to do a standardized driving cycle such as the NEDC cycle. Once we know the well-to-tank energy, the tank-to-wheel energy, the well-to-tank emissions, and the tank-to-wheel emissions, we can calculate the total well-to-wheel impact. This impact has two terms. For energy, first we must calculate how much mega joules of fossil energy are consumed for each mega joule of fuel consumed when the car is used. That is to say, multiply E1 by E2. Then, we add E2 if E2 is a fossil energy. This is true for petrol, diesel, natural gas, etc. Then, for greenhouse gas emissions, the principle is identical. A part is associated with greenhouse gas emissions to produce each mega joule of fuel consumed during use. Thus, we need to multiply G1 by E2 and then add the tank-to-wheel emissions, G2. For petrol, we obtain a total energy of 236 MJ per 100 km and CO2 emissions of 180 gCO2 per km. We can study several sectors thanks to the well-to-wheel analysis. A sector is characterized by a fuel and an engine specification. For instance, the petrol sector is made of petrol as a fuel and a spark-ignition engine or petrol engine. The conventional sectors are based on fossil ressources such as oil and natural gas. Oil can be used to create petrol or diesel. Petrol is used in a petrol vehicle with a spark-ignition engine and diesel is used in a compression ignition engine. Natural gas is compressed to become a natural gas for vehicles that is used in a NGV vehicle with a spark-ignition engine adapted to natural gas. There are also alternative sectors. For instance, petrol vehicles with a spark-ignition engine can use ethanol produced from biomass resources such as sugar crops, sugar cane or beetroot, or from lignocellulosic biomass. The specificity of this ethanol produced from biomass is that we consider the emissions during use to be zero because the CO2 emitted during the use of ethanol by the car is the same CO2 that has been absorbed by the plant during its growth. This principle is called carbon neutrality. For diesel vehicles, there are two alternative sectors. One uses biodiesel produced from vegetable oils or algae. The other is synthetic diesel produced from coal, natural gas or wood residues. For natural gas vehicles, the alternative sector uses biogas that can be produced from the methanization of household waste, dedicated cultures or algae. Biogas also produces zero emissions when used thanks to carbon neutrality. Another sector can be studied thanks to well-to-wheel analyses: the electric vehicle sector. Electricity can be produced from different energy sources: fossil energy sources such as oil, coal or natural gas, renewable energies such as solar or wind power, biomass, waste, or nuclear power. The electric sector also produces zero emissions during the use phase thanks to the use of electricity. Finally, the last sector we can study is the hydrogen sector that is used in fuel cell vehicles with an electric engine. Hydrogen can be produced from natural gas, biomass gasification or electricity by water electrolysis. Now that I introduced the principles and definitions of the well-to-wheel analyses and the sectors on which we can make this analysis, the next video will show you the results obtained with this analysis.