Knowing the present huge efforts from the truck manufacturers to electrify their drivelines this will probably lead to technical leap frogs towards fossil free road transport. Electricity supplied from batteries may well be the main solution in a short-term perspective. Since a couple of years hydrogen and fuel cells seems to become an optional alternative for electricity supply to the electric motor in long haul road transport. The option of grid-based electricity supply through a pantograph or similar solution has been discussed many years, previously existing in cities but today primarily for long distance transport providing continuous electricity supply. These three separate solutions for electrified trucks have various advantages and disadvantages that will determine their future role in the electrified road transport system.
For batteries; capacity (range), material use and charging abilities are critical success factors. The needed charging effect for truck batteries is significant and means large peaks in load that need to be met by the electric grid and electric production. Running a truck on batteries is based on two principal solutions. One is based on built in batteries and the second is based on battery swap to fully charged batteries (much advocated in China). Built in batteries requires a sufficient network of charging infrastructure that can deliver electricity at high effect in order to enable optimal logistics. The advantage by battery swap is its ability to enable charging at better conditions while vehicle stand-still is minimized. The drawback with battery swap is a likely need for more batteries, hence increased use of scarce metals and minerals. Both battery solutions presently lead to weight disadvantages that may lead to reduced cargo capacity.
Hydrogen and fuel cells as a source for electricity supply have for a number of years been considered to use too much primary energy due to losses in primarily hydrogen production but also in the propulsion phase. Furthermore, today´s hydrogen production is mainly based on fossil methane gas. With an estimated fuel cell efficiency of 60% and the electric motor´s efficiency of 90%, the overall propulsion efficiency will be somewhat higher than 50%. Certainly, somewhat higher than for a compression engine but still significant energy losses. If we to this equation assumes excess production of green electricity that can be used for fully renewable based production of hydrogen the situation becomes more favourable as the huge production losses and GHG-emissions becomes less of a problem. This may lead to a viable solution than can be used for long distance electric road transport. A risk that currently is being raised by researchers is the inability to measure leakage of hydrogen from production to the use phase. Hydrogen in the atmosphere may lead to methane with significant climate impact. It should be noted that this issue is highly uncertain and requires more research.
To operate electrified transport through a truck with a pantograph and roads providing continuous electricity supply requires significant investments in infrastructure and vehicles. Trucks will need double drivelines or added battery capacity for transport to and from the electric roads. Since the network of roads providing an electric grid will be limited the number of long-haul trucks will consequently be limited. Their ability to be used elsewhere will moreover be limited. A scenario could be ”Road trains” consisting of a strong tractor with a pantograph pulling maybe 4 – 6 semi-trailers in cargo relations with large volumes as a complement to present intermodal rail solutions.
By this simple overview my future bet is electric driven trucks supplied by batteries and fuel cells. To this I would like to see a significantly more functional, efficient and reliable intermodal rail system for long distance land transport supplied by renewable electricity. Either through a pantograph and a grid network or fuel cells where an electric grid is missing.