Important to Know
+ Batteries are a technology. Fuel is not.
Batteries continue to develop like Moore's law, at current speed about 15% improvement per year. That means that within 3 years, they ar 50% cheaper and have 50% more capacity. That means it is only a question of time before electric drive trains start taking over all modes of transport. Not in the very least because an all-electric drive train is much more efficient.
It is only a mattter of time before batteries become cheaper than chemical storage. These are just Li-ion developments. Other (graphene-based) batteries currently in development might accelerate these developments.
+ Fully electric drive trains are most energy efficient from the vehicle standpoint, including vessels
At least 60% of energy in a combustion engine is wasted. This number can be even higher for vessels, as they require pumps, separators and all types of auxiliary equipment for fuel. For an average vessel, about 30% of all produced energy goes to cooling the engines. A tremendous amount of waste energy is created just to keep the engine running. All-electric drive train for any vehicle needs only three things: a battery, a generator and a way to tranfer force onto the medium (like a wheel to land or propellar to water).
The overall efficiency is therefore greatly improved for an all-electric drive, and it includes other mechanical advantages as well. Where an internal combustion engine car or vessel has thousands of moving parts, an all-electric car only has about four hundred. For all-electric vessels, one can throw away pretty much everything there is in the engine room (pumps, backup generators, fuel lines etc.). The only caveat at the moment is of course the lower battery energy density compated to fuel and the cost. But, again considering the fact that batteries are developing exponentially, it is only a matter of time before it becomes more viable than regular combustion engine vehicles.
+ Currently, pure battery-electric propulsion seems mostly feasible for short-sea and DP operations
Battery volume and weight will pose a significant reduction of a vessel’s cargo carrying capacity, especially in the case of a hybrid vessel where the regular combustion drive-train is still installed. Additionally, energy density of batteries is still too low for long-term energy storage. Read more in our blog, Making the Impossible Possible
+ Battery electric vs hydrogen (heavy-duty vehicle)
According to Scania, a heavy-duty vehicle manufacturer who has invested in hydrogen technologies and is currently the only heavy-duty vehicle manufacturer with vehicles in operations with customers, the use of hydrogen for heavy-duty vehicle applications will be limited. This is because there is three times as much renewable electricity needed to power a hydrogen truck compared to a battery electric truck. A great deal of energy is lost in the production, distribution, and conversion back to electricity.
Repair and maintenance also need to be considered. The cost for a hydrogen vehicle will be higher than for a battery electric vehicle as its systems are more complex, such as an extensive air- and cooling system. Furthermore, hydrogen is a volatile gas which requires more maintenance to ensure safety.
However, hydrogen is a promising energy carrier; good way of storing energy over long cycles, and will play an important role in decarbonisation if produced in an environmentally friendly way. Scania looks forward to sourcing fossil free steel for its trucks as hydrogen will play a greater role in several industries.
Source: Scania