The Path to Think Big
(I) Evan Parry’s Proposal for making Nitrogenous Fertiliser
Evan Parry had already left New Zealand when, in 1920, the New Zealand Journal of Science and Technology published an account of his investigations, carried out three years previously, into making nitrogenous fertilizer from cheap New Zealand energy. An eventual decision to build such a plant would be made fifty -nine years later, though the energy source would not be electricity.
His idea was to locate manufacturing plant in one of the West Coast sounds which, as well as being a place to produce cheap electricity, would provide a deep-water facility for shipping.
Two methods were possible. An electric furnace could be used to combine calcium and carbon to produce calcium carbide which when heated and exposed to atmospheric nitrogen would convert to calcium cyanamide. Steam passed over the cyanamide would then give ammonia. Alternatively, an electric arc could be used to manufacture nitric oxide and then nitric acid. This latter method had been of importance to Germany in the 1914-18 war for making explosives when Chile nitrate had been cut off by blockade.
At the time, naturally occurring "saltpetre" or sodium nitrate from Chile provided two thirds of the world’s nitrogenous fertilizer, with most of the remainder being ammonium sulphate produced as a by-product in gas-works. Chile nitrate set the price with which any alternative had to compete.
As seen by Parry, the factors affecting the viability of a New Zealand plant were similar to those in a 1975 study. To provide a product competitive with imports a plant would have to be large but since the local market was small it would have to export. (New Zealand consumption of nitrogenous fertilizer had only been 1200 tons in 1914 and even with the Australian market only 4,500 tons had been used in the region.)
While cheap power and a large scale plant producing adjacent to deep water port facilities could give considerable advantages he considered that
"It is doubtful whether either of these two industries can be conducted successfully on the West coast sounds, owing to the great distance from the principal markets and the limited extent of the local market."
Having concluded that nitrogenous fertilizer manufacture would not be viable, Parry speculated as to what sort of industry might be able to take advantage of the "natural facilities" which "exist in an unusual degree on the West Coast Sounds."
He thought "the process which is the most likely to take advantage of these opportunities is the electro-metallurgical reduction of zinc ores and the treatment of complex ores generally”.
He noted the abundance of ores in Australia and that the Amalgamated Zinc Company (an ancestor of Comalco) had contracted with the Tasmanian government for a power supply for zinc-ore reduction. Since Australia did not have the natural advantages for power generation tha New Zealand had in the sounds, he thought a transfer of processing to New Zealand "extremely probable" and much more likely than nitrate manufacture.
Parry went on to suggest that "another possible use is for smelting Taranaki ironsands by electricity" but noted this was not an immediate prospect since the technology for electric smelting of the sands had still to be developed.
Parry’s proposal finally came to fruition in the 1970s when a new source of cheap energy finally led to a decision to build a nitrogenous fertilizer plant.