EV CO₂ Emissions in Spain

Introduction

Fig. 1: Percentage distribution of electricity generation in Spain in 2021. [2] (Source: L. Sanchez)

Electric vehicles (EVs) are more numerous on the streets of large cities. According to figures from the International Energy Transition Observatory, 6 million low-emission vehicles were sold in 2021 worldwide (electric vehicles, hydrogen or hybrids), which means an increase of 100% compared to 2020. [1] China prevails as the leader in EV adoption, followed by the European Union and the United States. EVs, whether battery or fuel cell, have a fundamental advantage: they do not emit polluting gasses directly. This allows, first: to have cleaner air in cities; and second: reduce total greenhouse gas emissions. However, battery EVs need to be plugged in to get the necessary electricity to power them, and that electricity comes from many sources, including some sources that emit carbon dioxide (CO₂).

It is no secret that EVs have CO₂ emissions associated with their manufacturing. Batteries represent an extra carbon footprint when compared to a combustion vehicle, but extra footprint is compensated by the lack of emissions. Whether emissions are offset sooner or later depends on several factors, including the sources of electricity generation in the country where the EV in question is plugged in. If the energy comes in large proportion from renewable sources, then the carbon footprint will be very small.

The question here is: How much CO₂ generates the electricity needed for an electric vehicle? How much indirectly does an EV pollute in Spain?

Today there are no EVs that are completely free of CO₂ in terms of manufacturing. So, we cannot say that EVs produce 0% emissions. However, if we compare it with internal combustion vehicles, and its effects on the environment, it is still much more ecological.

Energy Production in Spain in 2021

Fig. 2: EV Market in Spain in 2021 [1] (Source: L. Sanchez)

When it comes to energy production, Spain has been growing its share of renewable energy by an average of 3.7% over the last five years. In 2021, 256,387 GWh were generated in Spain, of which 112,810.3 GWh (48.4%) were obtained from renewable sources. [1] Electricity generation caused emissions of 35,901,184 tons of CO₂ in 2021, a 0.5% reduction from 2020 and 58% less than 2010. [2]

The main factor behind this improvement in emission reductions is the increase in wind and solar energy production. Wind turbines produce 10% more electricity than in 2020, with almost 60,000 GWh, largely thanks to the increase in installed capacity. Even more relevant is the jump made by photovoltaic energy, which in 2021 contributed almost 21,000 gigawatt hours, 36% more than in 2020 and 125% more than in 2019. Hydroelectric and nuclear energy slightly reduced their total production compared to the previous year. Hydroelectricity accounted for 11.4% of energy, while nuclear accounted for 21% of the total generation. When accounting nuclear energy production, the percentage of energy generated with zero emission sources increases to 68% (See Fig. 1 for a complete composition of the Spanish electricity network). [3]

34.5% of the electricity budget of Spain still comes from oil-equivalent. The amount of (CO₂) put into the air per Joule of energy consumed by an EV in Spain is therefore:

The numbers are relatively low, and would not have been possible without a record generation of renewables.

EV CO₂ Emissions

Fig. 3: Energy-related CO2 Emissions in Spain by sector, 2019. [8] (Source: L. Sanchez)

In Spain, the Tesla Model 3 was the most sold EV in 2021 (see Fig. 2). In order to find approximate emissions from the Tesla Model 3, we take generation data from 2021. The Tesla Model 3 consumes 16.1 kWh/100 km.

Thus we can conclude that 0.022 kg km^-1 emissions is too small for Spain due to high renewable penetration.

It is worth mentioning that there are also energy losses during the charging process. In our calculations we are going to disregard these losses because they are very different depending on the charger, the vehicle and the recharging conditions (ambient temperature, charging power, etc). I will also not take into account the energy losses in the network during transport. According to data from the REE (The Peninsular Electricity System) losses in the transmission network with respect to demand in Spain reach 1.85%. That is, for 100 kWh to reach the point of consumption, it is necessary to produce 101.89 kWh.

Comparison to Internal Combustion Vehicles

Now that we know how much CO₂ is emitted to generate the electricity needed to power an EV (see Fig. 3 for overall emissions in Spain), let's take a look at how much CO₂ emits an internal combustion vehicle. The average vehicle in Spain has a fuel economy of 35.4 km per gallon. [4] According to the EPA, every gallon of gasoline burned creates about 8.887 kg of CO₂ or 258.34 grams of CO₂ per mile. That is a difference of 235.44 grams of CO₂ between the indirect emissions of an electric vehicle and the direct emissions of an internal combustion vehicle taking into account the energy mix of Spain.

Fig. 4: Volvo C40 and Volvo XC40 Recharge (bottom)(Source: Wikimedia Commons).

When calculating the CO₂ caused by burning a gallon of gasoline, we have to also take into account the emissions generated during the extraction, the transportation of the crude oil to the refinery, the subsequent refining of the crude oil and the transportation of the gasoline to the gas station. In other words, the carbon footprint resulting from burning a gallon of gasoline is significantly greater than the calculated above. This precise calculation is highly complex. Furthermore, the combustion of hydrocarbons is also associated with the emission of carbon monoxide (CO), nitrogen oxides (NOx), soot particles (PM), hydrocarbons (HC) and sulfur dioxide (SO₂), which are known to be high pollutants.

A recent study took a sample of 8,966 oil fields in 90 countries that represent 98% of world production, and concluded that the average emissions generated globally is 10.3 grams CO₂eq/MJ, with large differences depending on the country where it is extracted and refined. [5] Algeria is the most polluting country, with 20.3 grams CO₂eq/MJ, this is due to the fact that field operators routinely burn large amounts of gas.Saudi Arabia, on the other hand, another major oil exporter, has the second-lowest carbon footprint because it burns little gas and its oil has low water content, so it spends less energy treating and separating the oil. The country with the lowest carbon footprint is Denmark, with 3.3 grams CO₂eq/MJ. Denmark, by the way, is also the largest oil producer in the European Union. [6]

Battery Production and its Environmental Footprint

Extracting the necessary raw materials, refining them and turning them into a cell requires a lot of resources and processes that lead to CO₂ emissions. But when does an electric vehicle begin to have a better CO₂ net balance than an internal combustion vehicle?

To calculate the difference between an electric vehicle and an internal combustion vehicle when it comes to battery manufacturing, we will take a look at data from Volvo, which is the only manufacturer to date that has published in detail the carbon footprint generated by the manufacturing of its vehicles, both internal combustion and electric ones. We will take a look at both the Volvo XC40 and C40 Recharge electric (see Fig. 4). According to Volvo data, manufacturing an electric C40 Recharge, including its battery, emits 10.6 tons more CO₂ compared to the XC40. [7]

100 kilometers in the XC40 emits 18.12 kilos of carbon dioxide (CO₂), while 100 kilometers in the electric C40 Recharge emits 2.54 kilos of CO₂. The Volvo XC40 emits 15.58 kilos more of CO₂ every 100 kilometers traveled.

Having seen the CO₂ emissions from the production of the electric Volvo C40 Recharge, and the emissions produced by the circulation of the combustion Volvo XC40, plus the emissions released by the Spanish energy mix, we can calculate that the footprint of manufacturing the C40 Recharge is offset at 68,000 Km. At that point, the electric C40 starts emitting less CO₂ than its combustion counterpart. [8]

© Luis Sanchez. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] J. Martinez-Lao et al., "Electric Vehicles in Spain: An Overview of Charging Systems," Renew. Sustain. Energy Rev. 77, 975 (2017).

[2] "El Sistema Eléctico Español," RED Eléctrica de España, 2021.

[3] "Spain 2021 Energy Policy Review," International Energy Agency, 2021.

[4] M. Pacce, I Sanchez, y M. Surez-Varela, "El papel del Coste de los Derechos de Emisión de CO₂ y del Encarecimiento del Gas en las Evolución Reciente de los Precios Minoristas de la Electricidad en España," Banco de España, Document Ocasionales No. 2021, Agosto 2021.

[5] M. S. Masnadi et al., "Global Carbon Intensity of Crude Oil Production," Science 361, 851 (2018).

[6] L. Canales Casals et al., "Sustainability Analysis of the Electric Vehicle Use in Europe for CO₂ Emissions Reduction," J. Clean. Prod. 127, 425 (2016).

[7] "Volvo C40 Recharge: Carbon Footprint Report," Volvo, 2022.

[8] O. Van Vlietr et al., "Energy Use, Cost and CO₂ Emissions of Electric Cars," J. Power Sources 196, 2298 (2018).