It is the fuel of the future. And will always be. That has been the problem with hydrogen. It may be abundant, clean and powerful, but it doesn’t exist in pure form on Earth.
Extracting it is both time-consuming and expensive. And the process can be dangerous too because it tends to be carried out at high temperatures or high pressure.
But a team of researchers in Israel have developed a new technology which could solve this problem. Their patented method, based on the chemical reaction of aluminium and water, may revolutionise the way we use the gas as a fuel.
“Our breakthrough is to produce hydrogen under regular conditions, at room temperature and normal atmospheric pressure,” Dr Shani Elitzur, who was involved in the research at the Israel Institute of Technology, explains.
“It is also not very expensive, simple to use and environmentally friendly.”
Unlike traditional sources of fuel like crude oil or gas, hydrogen is so light and reactive that it tends to combine with other elements – such as oxygen – extremely easily.
So to use it as a fuel, it must be split from those other substances. And that’s what scientists and engineers have found tricky to solve.
Traditionally, there are two ways to do this. The first is a process called reforming, in which high-temperature steam of up to 1,000C is used to extract hydrogen from methane. But this method is problematic because it is expensive and produces greenhouse gas.
The other established way to extract hydrogen is electrolysis, in which electricity is run through water to separate hydrogen and oxygen. While more environmentally friendly than reforming, it’s just as expensive.
What sets apart the method developed by Elitzur and her colleagues Professor Alon Gany and Dr Valery Rosenband is that it produces hydrogen at room temperature by simply mixing special activated aluminium powder and water.
The clever part of the process is how it gets aluminium and water to react with each other in the first place. Normally, when exposed to air, aluminium combines with oxygen to produce aluminium oxide. This oxide forms an impenetrable layer around aluminium that prevents it from reacting with water.
But by removing the oxide using a lithium-based activator, Elitzur and her team have been able to trigger and sustain a reaction between water and aluminium under normal atmospheric conditions.
The amount of hydrogen produced is quite remarkable.
In a recent demonstration in London, Elitzur pulled out a small container full of activated aluminium powder, and a bottle of still water. No more than a couple of minutes after she mixes the contents, a white smoke starts to billow out of a glass beaker: hydrogen.
Elitzur says any type of water can be used – fresh, waste, seawater, even urine. Modifying the aluminium powder with the lithium-based activator is also simple, safe, clean and relatively inexpensive. An added plus is that the extraction process is sustainable and regenerative: the chemical reaction’s by-product is aluminium hydroxide, which can be recycled back to aluminium or used as a fire retardant or smoke suppressant.
Once extracted, all that’s needed to render the hydrogen useable is a fuel cell to convert the gas into electricity.
According to Elitzur, 9kg of activated aluminium powder produces 1kg of hydrogen. That means the reaction rate is a remarkable 90 per cent efficient. Moreover, the technology could store up to 10 times more electric energy per unit mass than traditional batteries. A full-size electric car would need 50kg of aluminium and water to drive 500km, Elitzur says.
The technology is not far off being commercially viable, she explains. With the team now speaking to a number of potential financiers, the first product could be available within a couple of years.
Elizur says hydrogen produced in this way has numerous applications and can be used in electric cars, emergency generators and commercial aircraft.
“(Our) technology enables hydrogen production on site and on demand. There’s potential for commercialisation for sure. We know that it works and we know that it is scaleable.”
-
Hydrogen's potential
Scientists have long hailed hydrogen as a dream fuel. French author Jules Verne highlighted the gas’s promising future in his novel The Mysterious Island in 1874: “I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it…will furnish an inexhaustible source of heat and light…Water will be the coal of the future.”
NASA has used hydrogen fuel since 1970s to launch space shuttles and propel rockets into orbit. Liquid hydrogen is estimated to be at least three times more efficient than gasoline and other fossil-based sources of fuel.
For all its promise, however, hydrogen has been a commercial flop. On top of costly production process, storing and transporting it have been tricky. Since hydrogen is exceptionally reactive, it has to stay in compressed tanks at pressures 1000PSI (pounds per square inch). An alternative is to turn it into liquid at the temperature of as low as -253C.
Despite these drawbacks, efforts are underway to unlock hydrogen’s potential. As part of a clean energy drive, Japan plans to power 10 million homes, or a quarter of the country’s households, with fuel cells by 2020 and increase fuel cell vehicles on the road to 200,000 from the current 500.[1]
In the US, Amazon has bought a stake in hydrogen fuel cell maker Plug Power to power forklifts in its warehouses. Wal-Mart has similar plans. Plug Power forklifts can work around the clock because fuel cells recharge faster than batteries. A study by the US National Renewable Energy Laboratory found hydrogen models cost a tenth over the 10-year life span of an average forklift. [2]
California has perhaps the most over-arching hydrogen initiative. Residents that live near the state’s 30 fuelling stations can lease a hydrogen fuel cell vehicle that runs for 366 miles on a full charge for USD369 a month for three years, which comes with up to USD15,000 worth of hydrogen fuel.
[1] http://www.meti.go.jp/english/press/2016/0322_05.html
[2] https://www.nrel.gov/docs/fy13osti/56408.pdf
