Five alternative uses for Tiwai electricity

1. Shut down Huntly

The most straightforward idea is to simply channel all the hydropower from Manapōuri into the grid alongside the power from the other hydro lakes. The upside is simple: there’s enough power there to completely replace the Huntly power station, our biggest remaining burner of coal. Making New Zealand electricity 100 percent renewable sounds fantastic – but there are a couple of hitches. the transmission capacity to get all the electricity from Manapōuri to the North Island does not currently exist – and the price tag is around half a billion dollars.

2. Develop energy storage

A well-known issue with renewable generation is that production varies uncontrollably, and asynchrously, with energy use. Energy storage that can even out the availability over different timescales – day and night for solar, or seasons, for hydropower – comes in many forms. Pumped storage, currently being investigated by the Government, may help us mitigate the risk of dry years, or intermittent availability of wind and solar, by cycling water through a hydroelectricity station over and over again, with the input of those renewable energy sources when availability is high.

3. Produce hydrogen for decarbonisation of transport and industry

Decarbonising our energy sector will require us to look beyond electricity. The Interim Climate Change Committee has found that the most cost-effective change would be to phase out fossil fuels that doesn’t just mean Huntly and the milk powder drying plants that still burn coal. While electric vehicles are starting to make themselves seen (if not heard) on New Zealand roads, using hydrogen as a fuel is a competitive alternative for some applications, as per the UK National Grid report.

4 Manufacture silicon solar panels

When I first heard that was under consideration, I thought it rather a left-field idea. There is serious thought and work behind using the renewable energy at Tiwai to make silicon solar panels.Tony Baker, a mining engineer behind Southland Silica Ltd, has been working to get buy-in to the idea of using renewable energy to make poly-silicon for solar photovoltaics from local silica deposits  “Silica deposits such as Southland Silica has title to are uncommon but being located in close proximity to a world-class hydro plant like Manapouri make them globally unique,” he says.

5. Run green data centres

The fifth option that seems most readily viable, is the idea of using the energy locally to power data centres hosted in New Zealand. The carbon cost of data centres and the associated ICT industry is larger than that of pre-Covid air travel and increasing much more rapidly.

From a Newsroom article by Nicola Gaston an Auckland University physicist and Director of the McDaimond Institute for advanced materials and nanotechnology.