Nowadays, there is a paradigm about energy solutions concerning their cost and environmental impact, both aspects related to their efficiency. If for the UN and the EU, the main challenges are the promotion of sustainability and the decarbonisation of society, for the typical user, facing an energy crisis and other “phenomena” derived from the international situation, the value paid for energy is an fundamental aspect. If, on the one hand, there is a need to define good practices and behavioural change, on the other hand, the costs of energy vectors can compromise this objective. An example of this situation can be the “wave” of inflation that abounds across Europe, leveraged by the fuel crisis resulting from the war in Ukraine and market speculation. Thus Institutions assume a fundamental role and must be the mechanism for a profound reflection on the challenges society faces today and the consequences for future generations regarding complex processes related to globalization, climate change, energy dependencies, geostrategic conflicts, migrations, and digitalization, in sectors as diverse as food, health, housing, and transport. For this reason, institutions must create political, economic, technical, and other mechanisms that allow the common user to adopt good practices and make informed decisions.

Considering the current sustainability paradigm it´s opportune to reflect on sustainable mobility, defined as the transport or displacement of people or goods, using means of transport that contribute to the reduction of the consumption of fossil fuels, CO2 emissions, and losses in the energy chain.

However, and returning to the ordinary citizen, answers to concrete questions are required. Above all, it is essential to INFORM the citizen about the aspects to consider when a decision has to be taken, which are sometimes difficult. Considering a concrete case in the field of mobility:

“ I have to buy a new car ”. What car shell I buy? Combustion engine? In this case, gasoline or diesel? The LPG? Hybrid? Plug-in hybrid? 100% electric?

In other words, purchasing a simple car, which was previously a relatively straightforward process, where as a rule, the combustion engine was the only solution, is now a difficult operational research exercise. In addition, to carry out such an exercise, the citizen must be informed about the type of variables that will allow him to make an informed decision… and there are many:

a) Autonomy of the solution. Note that the ranges of Electric Vehicles (EV) are estimated by manufacturers in certain test situations that must be carefully read. For example, if the speed exceeds a certain value, the autonomy can drop considerably but this is not the only problem the temperature is also to be considered;

b) Solution. If a hybrid vehicle is considered, it should be noted that there are two types: the Hybrid and the Plug-in Hybrid. In the second case, the car will have autonomy to drive in exclusively in electric mode (reference values ​​around 50 km), a situation not possible in the first case.

c) The charging time. What is the charging time associated with a EV? What is the charging time associated with a Hybrid Vehicle? How long are we willing to wait to have autonomy in the vehicle? More autonomy leads to longer charging times, naturally.

d) Contracted power of the electrical installation. The power contracted for domestic use can be enough to charge the battery of a plug-in hybrid vehicle from a simple socket at home. However, if we want to reduce the charging time or if we have to charge a EV, even using available equipment on the market such as the “Wallbox”, it is very likely that we will have to increase the contracted power (kVA) of the installation and thus have an increase of the monthly bill not only related to energy (kWh) needed to charge the battery (which will naturally be done as much as possible at off-peak hours when energy has a cheaper price) but also for the increase in monthly power.

e) Wallbox. This is the socket that allows you to reduce the charging time. Instead of using a conventional domestic socket, a “Wallbox” can be purchased. Many models are available such as single-phase and three-phase models with the capability of load variation, for example, 7kW, 11Kw, 22Kw. This kind of equipment, depending on the features, have a cost associated with the purchase of an EV that has to be considered.

f) Maintenance. According to experts, a EV has less maintenance. However, if the solution is a hybrid vehicle, we have the combustion engine in addition to the electric motor and all its mechanical components. This issue is an important aspect.

g) State and tax support. This is an important issue. However, it is limited to a maximum number of vehicles. For example, in 2022, in Portugal, the limit number of vehicles financed by category is up to 1300 light passenger vehicles for private use, and there is also a limit to the selling price of the vehicle o 62500€ to be eligible for the incentive. In this context and in Portugal, it is essential to mention that the "single circulation tax" is reduced or non-existent for EVs.

h) Charging stations for electric cars. On holidays or work trips, the car's autonomy must be combined with the kilometres to be covered and the availability of charging stations on-site or during the journey. There are two types of charging stations: fast and slow. Fast charging stations are available on high-traffic roads, for example, on highways. Note that public charging stations, are more expensive than a domestic socket or a domestic charging stations “Wallbox”, so it should be a very well-considered aspect. A contract must be signed with an Electricity Trader for Electric Mobility (CEME).

i) Battery life time. Another point of great interest, namely if you choose to purchase a second-hand electric vehicle. Note that battery warranties on hybrid vehicles are, in many cases, around 5 years versus about 8 years on EVs. Here, the battery charge performed from a fast charge will have a greater influence on the battery life than a slower one. It will be important to know the battery history.

j) Access to the urban center. It may be a minor issue, but in a number of European cities, cars with certain combustion engines are no longer allowed to enter.

k) Environmental impact. This is a more straightforward answer question. In operating mode, a EV has no emissions, and a hybrid vehicle will have fewer emissions to the atmosphere than a conventional vehicle such as a combustion engines. The problem is treating batteries for the future after their useful life. There are brands on the market announcing almost total recycling of them. In other situations, studies are being carried out to analyse the feasibility of the second life of batteries, for example, to receive charge from renewables such as photovoltaic solar panels.

l) cost. An EV usually costs much more than a car with a combustion engine in the same segment. In addition, due to the lack of new cars for delivery, the increase in demand has led to an increase in the price of used cars.

And about the future, if the path is to electrify the car park, we will inevitably have a strengthening of the electrical networks and all their components with a transmission of the costs of these investments to the consumer. There are still other ways, such as the placement of photovoltaic solar panels in homes, that could help in charging electric cars. However, the electric car would have to be at home… going a little further, we see that batteries are starting to exist on the market for charging by solar panels that would allow discharge at night, for example, to charge the battery of the electric car. In this case, despite the high cost of these batteries… About hydrogen, there are already some cars powered by this fuel, but will it advance?