Hydrogen PowerPaste

People may be interested to learn of a new renewable option for transportation. The Franuhofer institute has introduced a new substance called PowerPaste, which is a paste-like substance that holds hydrogen using chemical bonds. PowerPaste is pumpable for large vehicles like ships, but it’s delivered in canisters for passenger vehicles which are loaded onto a vehicle and re-used when done It is not flammable or toxic. 

PowerPaste has a gravimetric energy density of 1.6 kwh/kg, compared to 12.67 kwh/kg for diesel, so PowerPaste has less than 12.6% of the energy density of diesel fuel. Still, that may be sufficient. Let’s calculate what kind of impact this would have on long-haul trucks.

A semi truck holds about 200 gallons of diesel on average (I just googled for this) across two fuel tanks. Diesel weighs 7.1 pounds per gallon, so the diesel fuel weighs 1420 pounds for a semi-truck. An equivalent amount of PowerPaste would weigh 11,244 pounds, so the PowerPaste would add 9,824 pounds to the weight of the fuel. This is approximately 22% of the net cargo capacity which a semi truck is allowed to carry (45,000 pounds in the USA, which I just googled to find out). A loss of 22% of cargo capacitty would require 28% more trucks to carry the same load.

Probably, trucks which use PowerPaste would have smaller tanks and would refuel more often. It might make more sense for the truck to carry enough fuel for 850 miles of range and then refuel every evening, as a matter of habit, rather than refuelling every few days or so. In which case, the weight of the fuel would be less than half what we assumed above, and would take up only 8.6% of the cargo space, requiring only 9.4% more trucks to carry the same load. 

If PowerPaste were used on ships which needed to cross the Pacific Ocean (which is the largest expanse of open water in the world), it would reduce the cargo capacity by 18% compared to bunker fuel. This is for the Maersk E class of container ships. Details of the calculation will be placed in the comments.

Trains are even less of a problem than trucks or ships, because they have a much lower ratio of fuel to cargo than trucks, and do not have to cross the entire Pacific Ocean without refuelling like ships.

PowerPaste has lower energy density than diesel or bunker fuel, but the energy density appears to be adequate for long-haul transportation. It requires only modest sacrifices of cargo capacity.

Of course, a crucial consideration is price. The PowerPaste is made out of common chemicals (magnesium) and is recycled, along with the canister. As a result, the overwhelming factor in price is likely to be the price of renewable hydrogen. I looked up a price prediction for renewable hydrogen at year 2030, given current gradual declines in prices over time. The expected price of hydrogen in 2030 by Bloomberg New Energy Finance is $5/kg. A kilogram of hydrogen has about the same energy as a gallon of diesel, so hydrogen and thus PowerPaste will likely be somewhat more expensive than diesel.

Another important consideration is refuelling stations. PowerPaste can be delivered to refuelling stations in tanker trucks, similar to gasoline or diesel. Furthermore, PowerPaste is not toxic and so would not require the expensive underground tanks for gasoline which must be periodically replaced. As a result, it’s possible that PowerPaste refuelling stations would be even less expensive and more common than gasoline stations are now. Since PowerPaste for small vehicles is sold in a canister, it could be sold at small stores devoted to other things, like Propane tanks are now. There could be even more widespread refuelling stations for PowerPaste than for gasoline.

In summary, PowerPaste is an imperfect substitute. It has a lower energy density than diesel, which means that some cargo capacity would be lost. PowerPaste is also not really liquid, but instead a kind of paste, so it must be delivered in recycled canisters for small vehicles.  The price will be modestly higher than diesel, even years from now.

Still, PowerPaste is an acceptable substitute for diesel in all cases. It has enough energy density to be used in long-haul trucking, ships that cross oceans, airliners, tractors, and other cases. PowerPaste would be an acceptable substitute in all of these cases with only a modest loss of cargo capacity. Furthermore, PowerPaste could have a tolerable price, not much higher than we pay for diesel now. It could be sold in ordinary refuelling stations, similar to gasoline stations. It is a can-do solution which will work in all circumstances where we use diesel now, despite its modest drawbacks.

To be clear, I’m not certain that PowerPaste is the solution that ultimately will be used. There are many ideas and suggestions for a replacement for diesel. We could use biofuels, synthetic e-fuels, ammonia, or other options which have not been devised yet. As a result, I’m not certain that PowerPaste will be the option ultimately decided upon.

However, there is at least one obvious, acceptable substitute for diesel in all use cases.

Our industrial civilization has vastly more time than needed to transition to it, before oil is exhausted from the ground. The transition to alternative energies and fuels has begun long before it was necessary, and there are obvious substitutes for all uses of diesel and other fossil fuels.