Gasoline and diesel engines, which are powered by fossil fuels, will soon be sidelined by climate change. Instead, new propulsion systems will be required. One fuel with a big potential is hydrogen. Hydrogen vehicles are equipped with a reinforced tank that is fueled at a pressure of 700 bar. This tank feeds a fuel cell, which converts the hydrogen into electricity. This in turn drives an electric motor to propel the vehicle.
Courtesy of Fraunhofer Institute for Manufacturing Technology and Advanced Materials
In the case of passenger cars, this technology is well advanced, with several hundred hydrogen-powered automobiles already in operation on German roads. At the same time, the network of hydrogen stations in Germany is projected to grow from 100 to 400 over the next three years. Yet hydrogen is not currently an option for small vehicles such as electric scooters and motorcycles, since the pressure surge during refilling would be too great.
However, researchers from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden have now come up with a hydrogen-based fuel that is ideal for small vehicles: Powerpaste, which is based on solid magnesium hydride.
“Powerpaste stores hydrogen in a chemical form at room temperature and atmospheric pressure to be then released on demand,” explains Dr. Marcus Vogt, research associate at Fraunhofer IFAM. And given that Powerpaste only begins to decompose at temperatures of around 250 °C, it remains safe even when an e-scooter stands in the baking sun for hours. Moreover, refueling is extremely simple. Instead of heading to the filling station, riders merely have to replace an empty cartridge with a new one and then refill a tank with mains water. This can be done either at home or underway.
The starting material of Powerpaste is magnesium, one of the most abundant elements and, therefore, an easily available raw material. Onboard the vehicle, the Powerpaste is released from a cartridge by means of a plunger. When water is added from an onboard tank, the ensuing reaction generates hydrogen gas in a quantity dynamically adjusted to the actual requirements of the fuel cell. In fact, only half of the hydrogen originates from the Powerpaste ; the rest comes from the added water.
“Powerpaste thus has a huge energy storage density,” says Vogt. “It is substantially higher than that of a 700 bar high-pressure tank. And compared to batteries, it has ten times the energy storage density.” This means that Powerpaste offers a range comparable to – or even greater than – gasoline. And it also provides a higher range than compressed hydrogen at a pressure of 700 bar.
Suitable for e-scooters – and other applications as well
With its huge energy storage density, POWERPASTE is also an interesting option for cars, delivery vehicles and range extenders in battery-powered electric vehicles. Similarly, it could also significantly extend the flight time of large drones, which would thereby be able to fly for several hours rather than a mere 20 minutes. This would be especially useful for survey work, such as the inspection of forestry or power lines. In another kind of application, campers might also use Powerpaste in a fuel cell to generate electricity to power a coffeemaker or toaster.
Powerpaste helps overcome lack of infrastructure
In addition to providing a high operating range, Powerpaste has another point in its favor. Unlike gaseous hydrogen, it does not require a costly infrastructure. This makes it ideal for areas lacking such an infrastructure. In places where there are no hydrogen stations, regular filling stations could therefore sell Powerpaste in cartridges or canisters instead. The paste is fluid and pumpable. It can therefore be supplied by a standard filling line, using relatively inexpensive equipment. Initially, filling stations could supply smaller quantities of Powerpaste – from a metal drum, for example – and then expand in line with demand. Powerpaste is also cheap to transport, since no costly high-pressure tanks are involved nor the use of extremely cold liquid hydrogen.
Pilot center planned for 2021
Fraunhofer IFAM is currently building a production plant for Powerpaste at the Fraunhofer Project Center for Energy Storage and Systems ZESS. Scheduled to go into operation in 2021, this new facility will be able to produce up to four tons of Powerpaste a year.
Since water is used to produce the needed hydrogen this system would not work at temperatures below freezing. Please comment.
The waste product is very probably magnesium hydroxide. This is completely safe and is drunk as part of milk of magnesia used as an antacid medicine. I\'m not sure what the pathway would be for taking this and recreating magnesium hydride in a circular magnesium economy.
Great invention, congratulations! Especially the by far higher energy density will open more usecases as we now can think of. The only puzzling are the laughable lobby \'arguments\' i see as comments here.. Peeps be careful, there are many paid fudders present, spreading false informations and sheer nonsense. Under the line this just prooves the concept that H2 is a powerful track to get rid of fossile powers.
The concept is probably viable, however the problem remains how to make H2 affordable and green. Electrolysis is very (20%) inefficient and using coal as in 100 years ago is illogical. However much the Australian mining industries love the idea.
I guarantee the waste would be recycled / recharged with h2 if this tech develops. You can\'t throw away 10 kg of expensive magnesium ($200 USD in Feb 2021) to get 1 kg of cheap hydrogen ($1 - $2) and ever expect any industry adoption. That would be making an electric car with a single use battery. Nobody would buy a new battery every 400 km.
That is a nice discovery, water is different or may be the same for some environments. The water might carry contaminants, such as arsenic and many other elements. Reçycling magnesium compounds and magnesium oxide generated from the waste might be environmentally unfriendly and costly it has been said before.
Interested to know the energy consumption involved in recycling the waste product, and if said energy will be sourced from a renewable energy source? Also if there are any environmental concerns for possible mishandling of either the paste or waste products. Additionally, this is an exothermic reaction, in some smaller applications heat dissipation may be a design hurdle. The \"paste\"approach I assume is a result of milling to increase the surface area of the MgH2 and increase the rate of reaction otherwise the kinetics of the reaction are too slow for sustained H2 production. While this is a great advancement in energy storage it seems it may be an energy intensive process: energy to mill and make paste, energy to collect and recycle waste and energy to distill the water for the reaction as well. I am not trying to be negative, I want to see this product succeed, I just also want to see renewable energy used for the many steps involved in making this a viable product. Otherwise it\'s just using coal derived power to charge batteries for an electric car...not exactly environmentally friendly in the big picture.
Paste + Water will weigh about 20 kg per 1 kg of H2 produced, making it <1/6th the energy density of gasoline or jet fuel. Also requires three tanks, since paste, water, and waste must all be contained separately. Also, fuel tanks will be complex, since this stuff does not \"flow.\" Something akin to a hypodermic syringe will be required for the paste. Finally, for aircraft. landing weight will be almost the same as takeoff weight, something pilots will not be thrilled with. Reaction is: MgH2 + 2 H2O + Paste --> 2H2 + Mg(OH)2 + Paste
Found on Green Energy something or other as a reference: A pumpable fuel rich in hydrogen would eliminate several key road blocks to wide spread adoption in transportation, including distribution infrastructure and storage safety and efficiency. The slurry, both before and after yielding the hydrogen, is not flammable, safe to handle, easy to store and can use current pumps and tanks used for diesel fuel, gasoline or water. The slurry is reacted with water to produce the hydrogen required. The metal hydroxide byproduct is captured and recycled.
I\'d to know whether what happens to the discarded waste. Is it regenerable? After all we don\'t want to be adding to land fill?