Dry-year energy study explores alternatives
Flooding Lake Onslow may not be the only option to provide New Zealand with clean energy in dry years but it is where the bulk of the investigation dollars have been spent.
The NZ Battery Project was established by the Ministry of Business, Innovation and Employment to find ways to ensure consistent power supply in years of low lake levels other than the coal-fuelled Huntly power station.
Project manager David Darby said to December 2022 $24.1 million had been spent on feasibility work and of that, $19.4 million had been spent on investigating pumped hydro at Lake Onslow.
Geotechnical work in the area cost $4.3 million and environmental investigations $637,700.
The top-three other possible solutions — geothermal, hydrogen and biomass — had only had desktop investigations, Dr Darby said.
No sites for any of those options had been identified.
Biomass would use chipped, debarked logs or torrefied pellets.
Torrefaction was a process that changed the biomass to provide better fuel quality and storage properties.
New torrefaction facilities would be required if that option was pursued, he said.
Access to biomass would have to be negotiated with commercial suppliers.
More forestry could be required to supply sufficient timber.
Hydrogen could be stored for long periods of time but biomass degraded over time, Dr Darby said.
The NZ Battery Project’s indicative business case was still expected to be presented to Cabinet early this year, he said.
