Solar investors say NT’s big battery in Darwin-Katherine grid is too small

Leading solar farm developers have welcomed the Northern Territory government plans to spend $30 million on a big battery in the region’s largest grid, but say an even bigger battery is needed to resolve all the issues and pave the way for more renewable energy.

The NT government over the weekend announced it would tender for a $30 million battery – likely to be sized around 35MW and around 30 minutes of storage – so it could save on the costs of gas for what’s known as “spinning reserve”. Those annual costs of $6,4 million would deliver a five-year payback for the battery, as Alinta has achieved for a similar sized battery at its Mt Newman gas facility in the Pilbara.

The NT government, which has set a 50 per cent renewable energy target for 2030, also announced a $6000 grant for batteries installed in homes and businesses, although to pay for this $800,000 project it slashed the solar feed in tariff from the long-standing “one-for-one” net tariff to a price of just 8c/kWh.

NT Solar, which proposes a 50MW solar plant at Livingstone, said the addition of a large battery energy storage system (BESS) in the Darwin-Katherine Interconnected System is a major step forward towards the central dispatch of ancillary services. But it says it should be bigger, and should coincide with the creation of a new ancillary services market.

“In order to fully support the addition of large-scale solar generators into the network, more BESS capacity will be required. We urge the government to complete the establishment of both a new electricity market and an ancillary services market for the NT,” NT Solar director Ilana Eldridge said.

Her comments follow that earlier this week from Alan Langsworthy, the lead author of the Roadmap to Renewables plan, who said the battery needed to be bigger to solve all the issues with the expansion of rooftop solar and to support new large scale solar plants.

It also urged the government to consider time-of-day tariffs – as proposed by the government commissioned Roadmap to Renewables report, because it would add more support to network security, along with demand side management such as load shifting.

NT Solar said it was experiencing a surge in customer interest in both home and commercial solar plus battery supply. “We continue our development works towards constructing the 50MW Livingstone Solar Farm, the only locally-owned generation-scale project currently in the works,” it said.

“The benefit of our solar farm feeding into a battery-stabilised grid will be downward pressure on electricity prices.”