The UK has announced it will close all coal-fired electricity generation plants by 2025.
If the UK could ditch coal for generating 30 per cent of its electricity, Fonterra could do the same for drying its milk powder, said Green Party energy spokesperson Gareth Hughes.
«The UK has identified the need to stop burning coal and find alternatives. It’s time Fonterra did too instead of building new coal burners, like the ones planned at the Studholme milk plant in Canterbury.»
Fonterra had alternatives available such as burning wood waste from the local forestry industry instead of coal, he said.
«Fonterra’s size and significance to New Zealand means it needs to show leadership and be part of the solution to reducing New Zealand’s agricultural emissions, instead of burning more coal.»
Unless it took action, Fonterra would by then be New Zealand’s largest coal user after Genesis Energy stopped burning coal in the Huntly power plant in 2018, he said.
But converting from coal to alternatives such as wood was not so simple, Fonterra’s managing director global operations Robert Spurway said.
About a third of Fonterra sites used coal and most of them were in the South Island where the co-operative did not have the option of using natural gas.
While Fonterra was looking at wood burning technology carefully, replicating it at scale was challenging and costly.
«At a time when our focus is reducing costs and generating better returns for our farmers, investing heavily in retrofitting our operations is not feasible.»
The co-operative had also trialled using miscanthus plants as a fuel source on a two hectare plot near Canterbury’s Darfield and had assessed technologies that allowed it to co-fire biomass in several of its newer plants.
This was included in Fonterra’s consent applications for the potential expansion of its Studholme site, and would be an option should that expansion go ahead, Spurway said.
Fonterra’s energy manager Linda Thompson said the co-operative had few options for energy in the South Island other than coal. The co-operative was constantly exploring alternatives to coal, but had yet to find one that was economically viable.
Converting a boiler so it could process wood mass had been investigated, but it de-rated its steam output. The company would still need a coal powered boiler to produce enough steam for the plant.
Fonterra’s boilers on its existing dryers were also ‘right sized’ and any replacement fuel had a similar energy content to coal.
The wood residue fuel would have to be sourced from a 100 kilometre radius around the sites for it to be economically and environmentally sustainable. If that wood was sourced from outside this radius, the increase in fuel to deliver the wood to the plant outweighed any savings gained from using wood.
«There isn’t the volumes that we need to replace the coal use. It is something we do look at and we struggle with the volumes we would need for a 100 per cent replacement, but it is something we are looking at.»
Coal typically produced 20 gigajoules a tonne to power boilers, compared with wood with 55 per cent moisture, which burned at 7 gigajoules a tonne.
Fonterra would need 50,000 tonnes of wood a year to power the 15 megawatt boiler it is commissioning at its Studholme plant. It would take three times the truck deliveries to haul that wood to the plant if it could obtain the volumes.
Using whole lumber logs was also an unfavorable option. Logs bound for the export market were too valuable to be burned as fuel. That meant pulp logs or residuals were the only option and Fonterra would have to compete with companies such as Carter Holt Harvey for this wood, she said
Source: Stuff
