At the end of 2020 here was a sharp decline in registrations
of new cars in Italy, we are talking about about 121,200 units, down 14.8%
compared to the same month in 2019. The electric vehicle market, on the other
hand, is on the rise , with peaks in the + 753.5% compared to the same month of
2019. These are the data reported in the analysis of the automotive market in
Italy prepared by the Energy & Strategy (E&S) Group of the Politecnico
di Milano.
In 2020, a negative trend was recorded for registrations of
petrol and diesel vehicles, with a decrease of 42% and 36.8% respectively. In
this loss-making situation, however, the hybrid vehicles are the winners ,
which recorded an increase of 225.8% in December 2020 compared to December
2019.
In light of these data, it is often asked whether the
benefits of electricity are really greater than conventional means powered by
fossil hydrocarbons, often the criticisms of electricity are based on the
production of electricity, accused of being more polluting in proportion than
to oil.
With this article we try to take stock of the situation at
least as regards the emissions of the famous greenhouse gases and various
direct and indirect pollutants , which derive both from the main industrial
processes of oil production and from the emissions of the means of transport.
We are talking about carbon dioxide (CO2), nitrogen dioxides and monoxides (NO2
and NO), atmospheric particles (PM10) and volatile organic compounds (VOCs).
Environmental pollutants
Carbon dioxide (CO2) is a colorless and odorless gas and
represents the main greenhouse gas in the earth's atmosphere (from its
uncontrolled production since the industrial revolution onwards it would in
fact result in an increase in the greenhouse effect, which contributes to global
warming by 70%). The transport sector is responsible for 30% of total CO2
emissions in Europe, of which 72% is produced by road transport alone. In an
attempt to limit CO2 emissions, the European Union has set a goal of reducing
transport emissions by 60% by 2030 compared to the levels recorded in 1990.
Nitrogen dioxide NO2 is a brown-red gas, pungent and highly
toxic odor: high levels of this pollutant can damage the respiratory system and
at the same time contribute to the formation of photochemical smog, as a
precursor of ground level ozone, and to the phenomenon of "acid
rain". Furthermore, we want to remember that every year about 4 million
new cases of asthma among children appear to be associated with NO2, produced
by the combustion of fossil fuels in vehicles , power plants and industries.
Another major player in the pollution of traditional
vehicles is the production of fine particles (PM), mainly attributed to the
exhaust gases that they produce with circulation. The PM10 has an aerodynamic
diameter equal to 10 thousandths of a micron eit is produced in particular by
diesel engines, which in fact are equipped with specific filters (DPF or FAP)
designed to reduce it . PM7 (diameter of 7 thousandths of a micron) can cause
problems with the oropharyngeal apparatus, PM 4.7 (diameter of 4.7 µm) can
affect the trachea and bronchi, while the thinner PM1 can even reach the
pulmonary alveoli .
Finally, there are volatile organic pollutants (VOCs),
compounds deriving from the combustion of gasoline and from the processing of
oil in the petrochemical industry, which are released in lower concentrations
than the pollutants listed above but are also the most dangerous. The most
important are Benzene and PAHs (polycyclic aromatic hydrocarbons) which are
recognized as mutagenic and carcinogenic to humans. In highly urbanized areas,
domestic heating and mobile sources, such as cars, are the most important
sources of PAH emissions.
After briefly illustrating the main pollutants, let's try to
define their trend and variability with respect to the use of electric vehicles
and petrol-powered means of transport. Given the large numbers of different
types of vehicles and their technologies, it is difficult to create models that
study the variation of polluting emissions compared to traditional vehicles.
Furthermore, the production of electricity can derive from
different sources and even in that case there is a considerable diversification
of pollution, passing from industrial production based on coal and natural gas
to that of renewable sources. However, we can try to extricate ourselves by
referring to several very recent studies that try to relate current consumption
to an increase in electric mobility.
Energy production
Let's start from the source of electricity production, very
promising in this field are the studies presented by the GSE, which show the
composition of the initial national energy mix of the electricity fed into the
grid for the years of production 2018 and 2019.
From these data it container be noted that the production of
electricity for our country is about 40% deriving from renewable sources ,
42.86% from natural gas and 8.52% from coal, an excellent figure compared to
that of 2005 in which the only 16% of electricity was obtained from renewable
sources. These data immediately put electricity at an advantage, also in view
of the European goal of 2030 which aims to produce this energy at 70-72% only
through renewable sources.
The Higher Institute for Ecological Protection and Research
has also published a report relating to the variation in total emissions from
1990 to today, resulting in a sharp decline of about 19.4% . Overall, from 1990
to 2019, gross inland consumption of energy from renewable sources more than
quadrupled from 6.5 to 29.5 Mtoe. In particular, the ISPRA analysis points out
that for the electricity sector, there is a rapid and constant decrease in CO2
emission factors with a strong decoupling between electricity generation and
climate-altering gas emissions.
However, as already mentioned, carbon dioxide is not the
only dangerous pollutantfor the environment and for man, if we refer to the
other pollutants we can see that their values are lowered to almost zero
through the production of energy with renewable sources. We refer to
atmospheric particulate matter (PM10), nitrogen oxides (NOx) and volatile
organic compounds (VOCs) previously illustrated.
For the production of NO2 we can evaluate the recent data
obtained by Barbara Dix and Joost de Gouw. Their study shows that between 2007
and 2019, in much of the United States, nitrogen dioxide pollution levels
decreased in urban areas thanks to cleaner cars and power plants . At the same
time, nitrogen dioxide emissions increased at the level of the Permian, Bakken
and Eagle Ford oil fields, respectively in Texas and New Mexico, North Dakota
and Texas.
As regards volatile organic compounds (VOCs), on the other
hand, we refer to the studies by Cynthia H. Whaley on the relationship between
the production of light gasolines and the production of electricity, in
particular the cracking process adopted for the production of light
hydrocarbons, such as gasoline, starting from medium-heavy and heavy crude oils
: this seems to be one of the processes that causes the greatest percentage of
formation of these pollutants.
The lack of this process in the production of electricity
and above all the fact that with an increase in electric vehicles the need to
produce so much petrol would disappear, makes the relationship clearly winning
for electricity.
Direct emissions
Let's talk now about direct emissions. First of all, there
are different types of electric vehicles, which can be identified with
different abbreviations. There are pure electric vehicles Battery electric
vehicles (BEVs) , which exploit the electricity stored in a battery inside the
vehicle: we are talking about cars, bicycles, scooters, motorcycles and
scooters, skateboards and unicycles. Then we have the Plug-in hybrid electric
vehicles (PHEVs) or hybrid vehicles with an electric motor and an internal
combustion engine that work separately.
Most PHEVs are passenger cars but there are also versions of
commercial vehicles and vans, trucks, buses, trains, motorcycles, scooters and
military vehicles. The range extended electric vehicles (REEVs) are battery
electric vehicles that include a small auxiliary internal combustion engine for
the sole purpose of recharging the battery. Unlike the Plug-in Hybrid, the
Range Extender is unable to operate the vehicle mechanically. The Hybrid
electric vehicles (HEVs)they are vehicles with a combustion engine and a
battery-powered engine. They are powered by the combustion engine, but at low
speeds (up to 50 km / h) and short distances (approx. 3 km), fully electric
propulsion is possible. The electricity needed to run the electric motor is
produced by the combustion engine.
We are therefore talking about different emissions depending
on the vehicle taken into consideration, moreover, depending on the vehicle we
are talking about different production processes, however we can report the
data used in the most general theoretical models, i.e. based on an evaluation
of the average between purely electric and hybrid media.
The manufacture and disposal of an electric car are now less
green than those of cars with an internal combustion engine even if several
researches are bringing admirable results relating to the production and
disposal of batteries and generator-engine components. Therefore, as far as
emissions due to production and disposal are concerned, conventional cars are
less impactful for a few percentage points.
However, for example in Italy, thanks to the new
registrations in 2020, which replaced the old highly polluting car fleet, it
was possible to save almost 1.2 million tons of CO2.The decrease in CO2 emissions
due to the new registrations in December 2020 is equal to almost 110,000 tons
per year.
The decline is largely due to hybrid vehicles (30.7%),
petrol (26%) and diesel (22.4%). But an important figure is given by the
contribution of pure electric vehicles that come to "weigh" for 13.3%
less CO2 emitted compared to a registration quota of 6%.
With regard to the pollution due to the production of
batteries, a 2017 study found that the production of a lithium-ion battery for
automotive releases on average 150-200 kilograms of CO2 equivalent per kilowatt
hour of battery produced: in the case of a vehicle electric with a 100 kWh
battery, 15-20 tons of carbon dioxide would be released for the production of
the battery alone, which has a life span ranging from 5 to 10 years. Making a
comparison with petrol or diesel vehicles, the latter, before releasing so much
carbon dioxide, would take (with an estimated mileage of about 2 000 km / year
and an estimated emission of 130 grams of carbon dioxide per kilometer) about
8, 2 years. However, this figure is to be taken with caution considering that
it does not evaluate the CO2 produced by the petrochemical process of producing
gasoline.
As for the direct emission of Volatile Organic Compounds
(VOCs), nitrogen oxides (NO2 and NO) and particulate matter, electric cars, but
also some hybrids, are approximated to an emission equal to zero.
In light of these considerations and therefore taking into
account the average energy mix in Europe, electric cars have already proven to
be more environmentally friendly than petrol or other petroleum-based fuels.
Finally, since an increase in electricity produced from renewable sources is
expected, electric cars are going to win a clearly positive balance in the
fight against pollution.
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