In the media, electric vehicles are constantly described as a miracle solution being able to cut emissions of the transport sector. At first sight, the solution seems promising: you charge your car simply as how you would charge a smartphone. The latest technologies of recharging stations promise faster-charging speeds than with your phone. In most articles and television coverage, the benefits focus here, conveniently skipping where the electricity is generated for these more ‘environmentally friendly’ cars. Unfortunately, the carbon footprint of an electric vehicle is intrinsically linked to the way the electricity used is generated.
An eminent French chemist, Antoine Lavoisier, once said: ‘In nature, nothing is created, nothing is lost, everything changes’. So, does this chemical principle apply to energy? The law of conservation of energy is governing our world at every level. It states that energy is conserved, even though its form may vary. It is important to keep in mind that any conversion process has an efficiency lower than 100%. For example, your smartphone adapter takes alternating current from the grid and transforms it to direct current, suitable for the battery. This operation has a given efficiency or a ‘cost’, if you want. Efficiency is usually defined as the ratio of two quantities, what you want over what you had. In the case of our adapter, we had alternative current, and we wanted direct current. The cost may be paid in heat, radioactivity, carbon dioxide emissions and so forth. In terms of our adapter, the ultimate cost is heat.
An enlightening comparison can be made between the efficiency of electric and petrol vehicles. Through the use of diesel/gasoline engine, petrol cars produce their own mechanical energy from gas with an efficiency typically around 20-30%. In the case of electric vehicles, a battery stores electricity produced in a remote power plant, which in turn, powers onboard highly efficient electric motor(s). However, the electricity generated can ultimately have a very high carbon footprint, e.g. coal thermal power plants. If large-scale power plants can be run 10% more efficiently than passenger car engines, the 10% increase is almost entirely lost in the successive inefficiencies of the electricity distribution, battery charger and battery itself. Actually, a battery never completely returns the stored energy – one of the reasons why your smartphone becomes warm. Most of the electricity being produced from fossil fuels, electric vehicles are thus neither more efficient nor more eco-friendly than conventional ones. But the media usually skips this exhaustive presentation.
Another interesting aspect is cost. Is it really cheaper to own an electric vehicle? If electric vehicles remain more expensive to buy, their use is usually cheaper. It is not even rare to see people bragging themselves about driving 100 miles for $3. The communication of some car manufacturers is even widely based on this fact. Is there a trick? You bet. When you go to the gas station, 70% of the bill is taxes. After VAT and income taxes, taxes on oil products represent the third source of income for the French state (old ‘TIPP’ now ‘TICPE’) with 23.9 billion euros. Similar situations exist in most of Western countries. For example, this tax is mainly used to build and maintain roads. People driving an electric car do not pay this tax and in a way they use a common good without financing it: roads. Some countries, such as large oil producers, do not implement a tax on oil products and you are then able to drive 400 miles for less than $5. Compared to that, electric vehicles with $3 for 100 miles already appear less competitive. How long will the situation stay this way? Probably as long as sales of electric vehicles remain anecdotal, and by anecdotal I mean as long as they represent less than 1% of the total fleet. Above, measures will be taken because 1% of 23.9 billion cannot be lost, particularly in a context of budget cuts.
Electric vehicle drivers do not save the world. Electricity used to charge the battery is usually produced at a high carbon footprint (except in few countries such as Brazil, Sweden just to name a few). Additionally, the battery remains a major challenge to recycle. In the end, they may even pollute more than a recent petrol car. Even though I remain a strong supporter of electric vehicles, I would like more communication about its real assets and liabilities. I would like to finish with a positive note. Electric vehicles are to some extent intrinsically superior to conventional vehicles. They allow you to reduce the emissions of the exhaust gases in cities (you rather pollute around your power plants in the countryside), provide some ancillary services to the grid (help to increase the reliability); and are quiet and highly efficient (the vehicle only). Powered mainly by renewable energy sources, the overall efficiency of an electric vehicle becomes much higher and with a very low carbon footprint.