This is an ongoing question. We talked about diesel earlier. Concerning internal-combustion engines, there will be changes in the sense that the size of the engine will always decrease. In spite of that, we will keep it to maintain that autonomy. As you can see, out of today's vehicles, the Volt is the most versatile. Why? Because it has a small combustion engine. With that, it can travel long distances.
What we are going to see is that engines will shrink. Also, carbon-neutral fuels will be sought. A lot of development on that is being done. Even though more is being done in Europe than here, Canada is well placed, thanks to timber and residues, to try to make a carbon-neutral fuel. That is one of the avenues. We see, given this roadmap, that there is always an internal-combustion engine.
Concerning batteries, and to answer the question about what the related problem is, I would say that it is energy density. In a tank with 400 litres of diesel, there is a huge amount of energy. That is why the internal-combustion engine has been so popular. The electric motor existed in 1910 because the energy density was not there to ensure flexibility for transportation. Today, the problem is very chemical and physical. With the materials and chemicals available to us, there is a limit to the quantity of energy we can put into a—