Har­ness­ing the power of the sun pays big div­i­dend

DEMM Engineering & Manufacturing - - ENERGY EFFICIENCY -

South Auck­land Forg­ing En­gi­neer­ing Ltd (SAFE Ltd) had a prob­lem – the cost of elec­tric­ity was go­ing only one way, and that was up. For a heavy forg­ing plant, this is bad news. The so­lu­tion, in the end, was the in­stal­la­tion of so­lar pan­els, a 68kW so­lar ar­ray of 360 pho­to­voltaic pan­els, ground­mounted at a 30-de­gree an­gle for high­est ef­fi­ciency, with a max­i­mum gen­er­a­tion of 62.4kW. Six in­vert­ers change this elec­tric­ity from DC to AC power re­quired for SAFE Ltd’s heat treat­ment furnaces, forg­ing plant and CNC ma­chines. It is one of the largest so­lar power plants in New Zealand.

Now 70 per­cent of the elec­tric­ity that SAFE. uses in year is gen­er­ated on site. Not that the com­pany gets to use all this en­ergy as the plant is not a seven-day-a-week op­er­a­tion and power stor­age tech­nol­ogy is not yet as cheap as it might be, so the sur­plus is fed back into the grid for which Merid­ian gives SAFE a credit, al­beit a de­creas­ing amount, says Richard Johnstone, some­what wryly. “But it’s not about the money, re­ally,” he says. “It’s about the en­vi­ron­ment. En­gi­neer­ing isn’t best known for be­ing green – it’s an en­ergy-hun­gry in­dus­try. But we can do our bit with new tech­nolo­gies com­ing along. I look for­ward to the day when stor­age be­comes more ef­fi­cient and cheaper. There are be­gin­ning to be moves in this area, tech­ni­cal ad­vances are be­ing made and the cost of bat­ter­ies is com­ing down.”

SAFE op­er­ates a heavy forg­ing plant, a large heat treat­ment fa­cil­ity, ma­chine shop, met­al­lur­gi­cal lab­o­ra­tory and train­ing pro­gramme all on the one three-hectare site, to pro­vide a “one stop shop” in­te­grated man­u­fac­tur­ing ser­vice. With drop-ham­mers and forg­ing presses to 1200 tons, SAFE Ltd pro­duces spe­cialised, cus­tomised, high-in­tegrity prod­uct for most in­dus­tries in New Zealand. In­no­va­tion and ca­pac­ity ex­pan­sion is a con­tin­ual devel­op­ment at SAFE Ltd, with a new process for Ti­ta­nium forg­ing and ex­tru­sion cur­rently un­der con­struc­tion.

SAFE did its sums on pro­jected rather than his­tor­i­cal us­age be­cause the com­pany is largely project-driven which makes for a lot of vari­ants. It wasn’t a huge out­lay to go so­lar but not in­signif­i­cant ei­ther, but the com­pany im­me­di­ately saw a re­turn on the spend and the in­vest­ment will def­i­nitely pay off – in droves when en­ergy stor­age tech­nol­ogy be­comes more af­ford­able, says Johnstone. The only blip in the fu­ture could be with line providers, who will find so­lar power users will be us­ing the grid con­nec­tors less and will there­fore want to pay less. Some leg­is­la­tion will have to be writ­ten around that, Johnstone reck­ons.

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