The solar car or mirage of the sustainable individual vehicle

Since 1987, dozens of cars covered in solar cells have gathered every two years in Australia to compete in the World Solar Challenge. The goal of this very special race: to cross as quickly as possible the 3,000 km of desert between the cities of Darwin and Adelaide, and this without any energy source other than that of the sun. Until now, limited to a few encounters with technophile enthusiasts, the solar car could soon make its way into our daily lives. In June 2022, Dutch company Lightyear unveiled a first model that is slated to hit the market this fall.

Thanks to its 5m2 solar panels on the roof and hood, its four motors in the wheels and its surface designed to be as aerodynamic as possible, it is heralded as a car. “driven by the journey itself”. By recharging on the road thanks to the sun, it can get up to 70 km of autonomy per day – provided the sunshine is optimal. The idea is therefore not to make the vehicle run alone thanks to the sun, because for this the solar panels must extend over an area equivalent to the roof of a semi-trailer, as explained by the engineer Laurent Castaignède, in Airvore or the dark side of transport (Ecosociété, 2018). Lightyear 0 therefore has a battery of 60 kWh, which gives it a range of approximately 600 km, to which will therefore be added the few tens of kilometers that solar charging achieves. The figures announced on Lightyear’s website are enticing: “6,000 to 11,000 annual kilometers of free, effortless and pure autonomy”. But according to Laurent Castaignède, they should be revised downwards because they involve a rather extreme form of eco-driving based on the sun: “It is assumed that the vehicle will be systematically exposed to sun and light”, explains the specialist. Especially since two hours of (intense) sunshine – according to the examples on site – would only give around twenty kilometers of autonomy, at best in spring and summer. A ridiculous figure if the idea is to drive “across borders” and “to destinations off the beaten track” (but sunny).

Stop the gadgets

In France, the transport sector represents the first source of greenhouse gas emissions in the country, accounting for almost 30% of total emissions. Whether on the side of the National Low Carbon Strategy or the Shift Project think tank, plans for mobility decarbonisation insist on the importance of connecting sobriety and technology. Concretely, this means carpooling as much as possible (to compensate for the low occupancy rate of the individual vehicles); make maximum use of soft mobility (cycling, walking, public transport); moderate the demand for transport by creating facilities that would make it possible to travel less far, less often, for longer, but also ensure the electric efficiency of the vehicles and the decarbonisation of the energy used. “The goal is to succeed in activating all these levers at the same time and to take advantage of the synergies to avoid rebound effects, explains Aurélien Bigo, researcher in the transport energy transition. These are generated by the fact that you only bet on technology or only on one of these levers – like the discourse around the green plan or the clean car, which in reality do not really exist.”. But the rebound effect is exactly what this “solar car” could cause: by presenting itself as a sober vehicle that would allow you to drive ever further in an “ecological” way (but without offering any kind of sobriety ), it would lead to an increase in demand and overconsumption, which would ultimately negate the virtuous effects it might have had initially: using low-carbon energy.

“The question that arises is how best to target the use of these technologies so that they are used where they are most relevant, says Aurélien Bigo. Installing solar panels on roads or on cars is tantamount to considering that they will be more virtuous there than on a truly suitable surface. We must not develop gimmicks, but real solutions”. Starting with using solar panels on surfaces that are constantly in direct sunlight (such as roofs) to increase their efficiency tenfold. Especially since it is always useful to remember: the production and maintenance of these panels is far from painless from an ecological point of view.

While many organizations agree on the need to continue to innovate and seek technological loopholes to address the current ecological crises, these developments must not overshadow their counterpart, which is still equally necessary: ​​sobriety on a collective scale. “Today there is a fairly significant focus in public policies on technological levers, but far too little on sobriety levers” notes Aurélien Bigo. The President’s recent speech could perhaps announce a change of direction, because the solutions are multifaceted on the condition that they are accompanied by the social measures that justify them. “A slowdown in mobility can occur by reducing the speed of cars – for example by moving to 30 or 20 km/h zones in cities, 110 km/h on motorways, 80 km/h on departmental and national roads… But also by to transport out of a modal shift and move towards slower means of transport such as walking or cycling where possible. »

In order to succeed in activating all these levers at the same time, it is first and foremost a general change in mentality that must take place. “We have to get out of the car systemsays Jacques Portalier, co-author of the Shift project’s report on the decarbonisation of transport, and think of it as an element of the mobility system that complements other transport systems”. But things are moving very slowly. Proven by Lightyear 0, sober in the materials it uses without being intended to be so in its use. The shift project is due to meet with the government at the start of the school year to further discuss the transport decarbonisation plan. If, as Jacques Portalier puts it, “A cultural revolution must be carried out around the way of perceiving the subject of mobility, both on a French and European scale”, this depends primarily on the goodwill of our leaders. Prone to rest sobriety on the crowd, to ask us to turn down the air conditioning or do not send attachments in our emailswould they also have the ability to attack SUVs and private planes.


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