NT solar farms still sitting idle after three years, now a consultant has been called in

Power and Water Corporation, the government owned utility in the Northern Territory, is seeking a consultant to provide advice on how to connect three utility-scale solar farms that have been sitting idle and gathering dust since they were built three years ago.

A tender issued by PWC, which closes next week, seeks a “specialist” power system engineer to provide a “final impact assessment” on the connection of the three 10MW solar farms built south of Darwin – Batchelor 1 and 2, and Manton.

All there were built in 2020 but have been unable to connect because of what has been described by Italian energy giant ENI, which owns two of the solar farms, as “onerous, unprecedented and indefensible”.

See our story: “Scared of solar:” Why the Top End’s first big solar farms are not switched on

It all comes down to the management of the Darwin-Katherine grid and its ability to deal with large amounts of rooftop solar, and now utility scale solar.

But ENI can’t expect any quick fix – the successful consultant will have nine months to complete its reports, and there is still no telling when the solar farms will actually be allowed to connect to the grid and generate power.

One of the problems behind the Darwin grid has been the lack of battery storage. The new 35MW/35MWh Darwin big battery is under construction, but it is unclear whether this will pave the way for the solar farms to be connected as its focus will be on reducing the number of back up gas generators.

Another facility – the 25MW Katherine solar farm further south – has been able to connect but has still not been dispatched, despite the addition of a 5.68MW and 3.44MWh battery system that would help it meet strict rolling forecast system imposed for the solar farms.

The Katherine facility is not mentioned in the consultant tender. RenewEconomy has sought further information from PWC.

Two other Department of Defence solar farms have also been delayed by changes in connection rules, a 9.2MW facility at Robertson Barracks, and a smaller 2.5MW facility at the RAAF’s Darwin base, even though they are both “behind the meter” and have batteries equivalent to one quarter of their capacity.

The one operating solar farm in the Darwin region of any size is at the Darwin airport, (pictured below) a 5MW facility which also operates behind the meter, but is not allowed to export any power, even to tenants at the airport itself.

Alan Langworthy, the former head of network company PowerCorp and the chair of the Roadmap to Renewables report that outlined the territory’s path to 50 per cent renewables, says there is no other grid system in the world that has some the same restrictions to the dispatch of renewable energy to the network.

“It’s a ridiculous situation that is prohibiting any dispatch of medium to large scale renewables to the grid,” he says.

The irony is that the NT could, within years, play host to the world’s biggest solar farm – the 20GW Sun Cable project that seeks to export power to Singapore, as well as to a new green manufacturing hub in Darwin.

That project, however, will be backed up by up to 42GWh of battery storage if it goes ahead as planned, although its future is also subject to a sale by tender after it was placed in administration due to a disagreement over the business model by billionaire backers Andrew Forrest and Mike Cannon-Brookes.

In its tender document, PWC says it requires a specialist power system engineering consultant to undertake Final Impact Assessments (FIA) of Batchelor 1 Solar Farm, Batchelor 2 Solar Farm and Manton Solar Farm.

“FIA can be done by a consultant remotely,” it says. “FIA is critical and extensive model assessment study required to investigate further impact of the proposed connection (or plant) on PWC network system strength and security.

“The consultant must have comprehensive knowledge of the PWC power network, systems, codes and regulations to ensure all requirements are met, and must have expertise knowledge of the PowerFactory software, particularly EMT modelling and associated requirements.

“The consultant must be available to undertake work on a short-notice and with short turnaround time which meets regulatory requirements.” It notes that PWC is the first utility in Australia to use PowerFactory in order to conduct such FIA studies.