Approval for a new transmission line in the Pilbara is expected to pave way for a large scale solar farm and a battery storage facility to help power some of the country’s biggest mining operations.
Alinta Energy this week won approval from W.A.’s Economic Regulation Authority to extend the transmission line that currently connects the Newman gas generator and Newman battery to Gina Rinehardt’s Roy Hill iron ore mine, onwards to the Christmas Creek and Cloudbreak iron ore mines operated by Fortescue Metals.
The addition of a 65km long 220kV transmission line will enable Alinta to install one, and possibly two 60MW solar farms near those Fortescue operations, as well as a new battery storage installation following the success of the Newman battery in boosting reliability and reducing the cost of fossil fuel generators.
The two Fortescue mines are currently powered by diesel, and the construction of a solar farm at the scale contemplate by Alinta would signal one of the most exciting developments in the supply of electricity to the mining industry.
RenewEconomy revealed the proposal to build the first 60MW solar farm back in August, drawing on an application made to the Department of Water and Resources for land clearing in the area. Alinta has since suggested in presentations that two different solar farms of that size may be built in the Pilbara.
The proposed shift to solar is not a surprise. Fortescue had flagged its interest in solar power last year, recognising that it could deliver a significant reduction in costs from the mostly diesel plants that supply its mines.
Incidentally, Fortescue recently flagged the conversion of approximately 100 haul trucks at the Chichester Hub will see Fortescue become the first iron ore operation in the world to have a fully autonomous haulage fleet.
Other miners have also made some inroads into renewables, most notably the Degrussa copper mine in Western Australia, and the Weipa bauxite mine in northern Queensland.
Oz Minerals has also signed a transmission investment agreement with US-based SolarReserve, looking to extend a line out beyond its proposed Aurora solar tower and storage facility near Port Augusta, to unlock more solar resources near the miner’s yet to be developed Musgrave and the expansion of existing projects.
Oz Minerals said in its latest quarterly report this week the work on the new line is progressing, with negotiations with landowners and government agencies, survey work and a connection agreement with ElectraNEt is expected to be finalised this quarter.
It said in March earlier this year that it is looking at renewable energy options for the expansion of its Prominent Hill mine, the development of the $1 billion Carrapateena project, and the possible development of West Musgrave, but also noted in its latest quarterly report that wholesale market falls could deliver a 20 per cent saving to its current bills.
Back to Alinta, as we reported last week, the 35MW/11.4MWh battery next to the Newman gas-fired generator has been an eye-opener, and proved it can operate in standalone mode, has grid-forming capability, and can provide frequency control by acting as a virtual generator.
It’s the ability to provide enough fault current to keep the grid stable whenever everything else goes pear-shaped that has proved the most valuable. The nature of such grids means that generators can be lost, and large loads can be lost.
“We have had situations where we had no thermal generators, and the battery’s been able to hold the transmission line by itself,” Alinta’s Gary Bryant told RenewEconomy
And the same thing has occurred when up to 80 per cent of load is suddenly lost. “The battery has responded within milliseconds, absorbing the excess load until the system restabilises to ensure no loss for other customers,” Bryant says.
Previously, because of the slower response of the gas generators, cascading losses were often unavoidable. “We’ve definitely had fewer outages – our customer’s very happy with improvement of power quality,” he says.
Bryant said last week that as that network is pushed out further “it is inevitable” we will put in a second unit, but that also depends on how much renewables is put on the grid.
“We are looking at extending out network beyond Roy Hill, and using solar as much as we can. The more (solar) we put there, the more we need system security.”
