Ammonia, a renewable fuel made from the sun, air and water, could power the globe without carbon

(ORDO NEWS) — Using large amounts of solar and wind energy, Australia is aiming to replace the messy, 100-year-old recipe for ammonia production.

According to Douglas McFarlane, a chemist at Monash University outside Melbourne, Australia’s ancient arid landscapes are fertile ground for new growth: vast forests of wind turbines and solar panels.

There is more sunlight per square meter in this country than in any other, and powerful winds blow over its southern and western coasts.

Overall, Australia’s renewable energy potential is 25,000 gigawatts – one of the highest in the world and about four times the planet’s installed electricity generation capacity. However, with a small population and a lack of ways to store or export energy, its renewable resources are practically not used.

This is where McFarlane comes to the rescue. For the past 4 years, he has been working on a fuel cell that can convert renewable electricity into a carbon-free fuel: ammonia.

Fuel cells typically use the energy stored in chemical bonds to generate electricity, while MacFarlane does the opposite. In his lab on the third floor, he demonstrates one of the hockey puck-sized devices made of stainless steel.

Nitrogen gas and water are supplied through two plastic tubes on the back of the device, and electricity is supplied through the power cord.

Through a third tube on the front, it silently exhales ammonia gas, all without the heat, pressure, and carbon emissions normally required to produce this chemical. “It’s breathing in nitrogen and breathing out ammonia,” MacFarlane says, beaming like a proud father.

Companies around the world already produce $60 billion a year of ammonia, mostly as fertilizer, and MacFarlane’s device could allow them to do it more efficiently and cleanly. But he has ambitions to do much more than just help farmers.

By converting renewable electricity into an energy-rich gas that can be easily cooled and compressed into liquid fuel, the Macfarlane fuel cell efficiently stores sunlight and wind, turning them into a commodity that can be shipped anywhere in the world and converted back into electricity or hydrogen gas for fuel cell vehicles.

The gas coming out of a fuel cell is colorless, but from an environmental standpoint, says McFarlane, ammonia is about as environmentally friendly as it gets. “Liquid ammonia is liquid energy,” he says. “This is the sustainable technology we need.”

Ammonia – one nitrogen atom bonded to three hydrogen atoms – may not seem like an ideal fuel: Used in household cleaning products, this chemical has a foul odor and is toxic.

But its energy density by volume is almost twice that of liquid hydrogen, its main competitor as a clean alternative fuel, and it’s easier to transport and distribute.

“It can be stored, transported, incinerated and converted back into hydrogen and nitrogen,” says Tim Hughes, an energy storage researcher at manufacturing giant Siemens in Oxford, UK. “In many ways, this is ideal.”

Researchers around the world are seeking the same “ammonia economy” perspective, with Australia positioning itself as a leader. “It’s just getting started,” says Alan Finkel, Australia’s chief scientist based in Canberra.

Federal politicians have yet to propose any major legislation to support renewable ammonia, Finkel said, which is perhaps understandable for a country that has long been committed to exporting coal and natural gas.

But last year, the Australian Renewable Energy Agency said building an export economy for renewables was one of its priorities. This year, the agency announced A$20 million in seed funding to support the export of renewable energy technologies,

In Australian states, politicians are looking at renewable ammonia as a potential source of jobs and tax revenue, says Brett Cooper, chairman of Renewable Hydrogen, a Sydney-based renewable fuels consultancy.

In Queensland, authorities are discussing the possibility of establishing an ammonia export terminal in the port city of Gladstone, which is already a hub for the delivery of liquefied natural gas to Asia. In February, the State of South Australia awarded A$12 million in grants and loans to a renewable ammonia project.

And last year, an international consortium announced plans to build a $10 billion combined wind and solar power plant, known as the Asia Renewable Energy Center, in Western Australia.

While most of the 9,000 megawatt project’s electricity will come via a submarine cable to power millions of homes in Indonesia, some of that energy could be used to produce ammonia for long-distance exports.

“Ammonia is a key driver for renewable energy exports,” says David Harris, research director for low-emission technologies at the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO) Energy in Pullenvale. “It’s a bridge to a whole new world.”

But first, renewable ammonia advocates will have to supplant one of the biggest, dirtiest, and most time-honored industrial processes in the world today, called Haber-Bosch.

The ammonia plant, a metal metropolis of pipes and tanks, sits where the red cliffs of Western Australia’s Pilbara Desert meet the ocean.

Owned by Yara, the world’s largest ammonia producer, and built in 2006, the plant still sparkles today. It is at the forefront of technology and is one of the largest ammonia plants in the world. However, it is based on steel reactors, which still use a century-old ammonia production recipe.

Until 1909, most of the planet’s ammonia was produced by nitrogen-fixing bacteria. But in the same year, the German scientist Fritz Haber found a reaction that, using iron catalysts, breaks the strong chemical bond that holds together nitrogen molecules, N2, and combines atoms with hydrogen to produce ammonia.

The reaction requires brute force – up to 250 atmospheres of pressure in tall, narrow steel reactors – a process pioneered by the German chemist Carl Bosch. The process is quite efficient; about 60% of the energy used in the plant is ultimately stored in ammonia bonds.

When scaled to plants the size of Yara, the process can produce massive amounts of ammonia. Today, the plant produces and ships 850,000 metric tons of ammonia a year—more than twice the weight of the Empire State Building.

Most of it is used as fertilizer. Plants need nitrogen, which is used to build proteins and DNA, and ammonia supplies it in a bioavailable form.

Haber-Bosch reactors can produce ammonia much faster than natural processes, and in recent decades this technology has allowed farmers to feed a growing world population. It is estimated that at least half of the nitrogen in the human body today comes from a synthetic ammonia plant.

The Haber-Bosch technology led to the “green revolution”, but the process itself is not “green”. It requires a source of hydrogen gas (H2), which is separated from natural gas or coal during a reaction using pressurized superheated steam.

This leaves carbon dioxide (CO2) behind, accounting for about half of the emissions from the entire process. The second feedstock, N2, is easily separated from air, which is 78% nitrogen.

But it takes more fossil fuel, and therefore more CO2, to create the pressure needed to combine hydrogen and nitrogen in reactors. Emissions are on the rise: Ammonia production consumes about 2% of the world’s energy and produces 1% of CO2.


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