Could am­mo­nia be ship­ping and avi­a­tion’s green fuel of the fu­ture?

In­dus­tries may have no other op­tion in or­der to cut emis­sions, say ex­perts. Hasan Chowd­hury re­ports

The Daily Telegraph - Business - - Business -

On the high seas off the coast of Scan­di­navia, cargo ships are a fa­mil­iar sight fer­ry­ing sup­plies to the re­gion’s oil plat­forms. If sci­en­tists have their way, a new type of ves­sel could soon ap­pear on the hori­zon, pow­ered not by pol­lut­ing hy­dro­car­bons but by some­thing else: am­mo­nia.

Wärt­silä, the world’s big­gest ship en­gine man­u­fac­turer, an­nounced this month that it was work­ing on the first ever full-scale test of am­mo­nia as a green fuel in ships.

The goal? The Fin­nish group aims to find bet­ter ways to com­ply with global ef­forts to tackle cli­mate change as the In­ter­na­tional Mar­itime Or­gan­i­sa­tion pushes the sec­tor to cut its emis­sions in half by 2050.

“It is a huge un­der­tak­ing to change the ship­ping in­dus­try,” says Egil Hys­tad of Wärt­silä. “Ship­ping is emit­ting car­bon diox­ide cor­re­spond­ing to 40m per­sonal cars ev­ery year. That’s 1bn tons of car­bon diox­ide.”

At one level, am­mo­nia is just a gaseous mix of ni­tro­gen and hy­dro­gen, bet­ter known for its use as a fer­tiliser.

But like Wärt­silä, many see am­mo­nia’s po­ten­tial to serve as a sus­tain­able fuel by car­ry­ing hy­dro­gen, help­ing to de­car­bonise oper­a­tions.

Ear­lier this year, com­pa­nies in­clud­ing Bri­tish en­gi­neer­ing firm Lloyd’s Reg­is­ter and Sam­sung’s ship­build­ing di­vi­sion signed on for a project to build an am­mo­nia-fu­elled tanker. So has its time ar­rived?

For the ship­ping in­dus­try, there is lit­tle choice but to give it a try. Hy­dro­gen alone, tabled as an al­ter­na­tive, falls flat as a fuel given its rapid boil-off rate.

Any hopes of elec­tri­fy­ing ships are likely to fail too, given the bat­ter­ies re­quired would sim­ply be too large, says Dr Tris­tan Davenne, en­gi­neer on a green am­mo­nia project in Har­well. “They’re cer­tainly not scal­able up to that level at the mo­ment.”

One chal­lenge for sec­tors such as ship­ping look­ing to am­mo­nia is to find a way of pro­duc­ing it that doesn’t gen­er­ate harm­ful emis­sions.

Typ­i­cally, am­mo­nia is made in a process known as steam re­form­ing. Hy­dro­gen is gen­er­ated from a re­ac­tion in­volv­ing methane, wa­ter and air, and then com­bined with ni­tro­gen in a process known as the Haber method. How­ever, car­bon diox­ide is pro­duced as a by-prod­uct – un­der­min­ing its use to tackle cli­mate change.

Dr John Con­sta­ble, direc­tor of the New En­ergy Foun­da­tion, sees one fix for this that banks on car­bon cap­ture and stor­age, a rel­a­tively un­proven tech­nol­ogy that sucks car­bon diox­ide from the air and stores it deep un­der­ground. “If you can cap­ture the car­bon from steam methane re­form­ing, it may be clean at the point of con­sump­tion,” he says.

An­other method pick­ing up trac­tion from Wärt­silä in­volves the use of elec­tric­ity gen­er­ated by wind farms to split wa­ter into its com­po­nents of hy­dro­gen and oxy­gen through a process known as elec­trol­y­sis.

That hy­dro­gen can then be com­bined with ni­tro­gen pulled from the at­mos­phere to cre­ate am­mo­nia in a way that has cut car­bon emis­sions al­to­gether. For years, the method has proved too costly, but Hys­tad claims 400 gi­gawatts of wind tur­bines are due to be in­stalled in the North Sea be­tween now and 2050, more than 20 times the cur­rent out­put.

With clean op­tions of gen­er­at­ing am­mo­nia emerg­ing, the next chal­lenge in­volves turn­ing it into a form that can be used as fuel. Wärt­silä is ex­plor­ing the pos­si­bil­ity of pump­ing am­mo­nia 70m be­low sea level where high pres­sure can turn it into a liq­uid, while an­other op­tion in­volves cool­ing the gas to -40C to liq­uefy it.

Once in a liq­uid form, am­mo­nia can be used in a retro­fit­ted in­ter­nal com­bus­tion en­gine, or can gen­er­ate elec­tric­ity in a re­ac­tion driven by a de­vice known as a fuel cell.

The abil­ity to cre­ate green am­mo­nia is open­ing up po­ten­tial ap­pli­ca­tions far beyond the high seas too. A study led by Davenne’s team has been in­ves­ti­gat­ing the po­ten­tial for am­mo­nia to re­place kerosene as the go-to fuel in the avi­a­tion in­dus­try.

At a cruis­ing al­ti­tude, am­mo­nia could sit in the wings of a plane as a liq­uid, and the en­gine would need few changes.

But there are some real hur­dles to over­come.

In planes, am­mo­nia could strug­gle as its en­ergy den­sity is a lot lower than kerosene, mean­ing much more fuel will be needed on-board. For ship­ping, the cor­ro­sive­ness of am­mo­nia presents “a real prob­lem for the in­tegrity of the en­gine”, ac­cord­ing to Con­sta­ble, and could pose safety threats to op­er­a­tors.

Both pro­cesses of gen­er­at­ing am­mo­nia re­quire large amounts of fresh wa­ter too.

“Bear in mind it won’t be re­turned to the wa­ter ta­ble be­cause when it’s burned it ob­vi­ously goes off as wa­ter vapour,” Con­sta­ble says.

How­ever, sea­far­ers may have no choice but to ac­cept am­mo­nia’s time has come. “It’s the only way of de­car­bon­is­ing 100pc for trans­port,” he says.

‘Ship­ping is emit­ting car­bon diox­ide cor­re­spond­ing to 40m per­sonal cars ev­ery year’

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