Tailem Bend solar farm gets operator approval for self-forecasting technology

South Australia’s 95MW Tailem Bend solar farm has become the first renewable project of its kind to be granted approval for self-forecast generation by the Australian Energy Market Operator (AEMO).

The project’s developer, Vena Energy Australia, said on Monday that the forecasts from Proa Analytics technology had been approved after an eight-week assessment period by AEMO.

The milestone makes Tailem Bend the first semi-dispatched renewable energy project in the National Electricity Market in Australia to switch from AEMO’s forecasting tool to a self-forecasting model.

It’s an intriguing development for Tailem Bend, which is one of the first and biggest solar farms to be affected by clauses that require it to be switched off at times of negative prices, and which is also considering the addition of battery storage as part of an overall expansion. The market will be watching with interest as to how this fits together.

It also marks the first time Proa’s self-forecasts have been accepted into AEMO’s centralised dispatch process that orchestrates power generation across southern and eastern Australia.

“Self-forecasting has the potential to garner significant benefits to the wider management and operation of the market and renewable industry,” said Vena Energy managing director, Anil Nangia.

“This includes greater industry capability and responsibility to the communities being serviced by renewable generation, improved system security and stability, reduced Frequency Control Ancillary Services (FCAS) costs of the generators, and more efficient market outcomes”.

Tailem Bend, officially opened in May, came into full operation in April after having to be pared down from its original 108MW capacity due to connection and system constraints.

An installation of forecasting hardware and software, including on-site equipment such as sky cameras and pyranometers, was completed by Proa in mid-June, and began submitting generation forecasts in July.

The technology uses geostationary satellite imaging, on-site cloud imaging and other data to provide highly accurate forecasts of solar generation from 5 minutes up to 7 days ahead.

As we have reported, Taliem is one of a number of solar farms to have signed a long-term power purchase agreement with Snowy Hydro that includes a “zero price” clause. This means the off-taker will not pay for the output of the solar farm at the contracted price if the market price falls into negative territory.

In the case of Tailem – which has plans for a stage 2 solar expansion and the addition of battery storage – this tweak in the deal resulted in the solar farm being switched off for long periods in its very first weeks of operation, in May. And again just this month. It has been switched off on numerous occasions in September.

How the self-forecasting technology will benefit Vena Energy, or speed up the case for the added battery storage system for Tailem, is unclear.

But Proa technical director Victor Depoorter said the key benefit for all parties was more accurate forecasts – which explains why the Australian Renewable Energy Agency and AEMO teamed up to drive the switch to self-forecasts.

“Providing more accurate forecasts of solar and wind generation means that all other assets across the NEM are used more efficiently,” Depoorter said.

“This enhances system security, reduces electricity prices and reduces emissions. The first self-forecast provided by a renewable generator is a significant milestone for Australia’s energy industry.”

Proa also leads a two-year ARENA funded project to demonstrate its new solar forecasting technology at three other solar farms: Kidston and Oakey 1 in Queensland and Bannerton in Victoria, with $728k ARENA funding and total project budget of $1.4 million.