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South Australian electricity network’s rooftop PV trial set for launch

Since July 2020, SA Power Networks has been refining technology and stakeholder engagement mechanisms to enable dynamic solar exports to the grid, potentially ending an era of severe export limits on new customers in rooftop-solar-rich parts of the South Australian network and other jurisdictions.

From pv magazine Australia

Sept. 23 will mark the start of SA Power Networks’ (SAPN) 12-month Flexible Exports Trial, which has the potential to double the amount of rooftop PV participating in the South Australian electricity network, by using smart technology to manage the flow of solar exports in response to congestion signals.

New and upgrading solar customers in parts of the grid that can’t handle more solar feed-in at certain times of the day, for short periods of the year, will no longer be limited to a year-round 5 kW of solar exports. That measure was introduced to protect grid stability, but it has proved to be a blunt instrument that unfairly affects new solar customers, compared to those who got in early and have been unrestricted in their exports.

“We are in the early stages of this new technology, and Flexible Exports is a world first that will help us accommodate more solar on our network,” said Mark Vincent,  SAPN’s general manager of strategy and transformation.

Flexible Exports will initially allow new systems connecting in the most solar-loaded of Adelaide’s southern suburbs to make a great leap in export capacity, if they are prepared to install compatible smart inverters – from either the Fronius SnapINverter Primo series or the GroWatt MIN-TLX line – paired with the energy-management technology of Australian company SwitchDin’s Droplet gateway.

“Based on network conditions experienced over the past 12 months, the flexible option would allow customers the opportunity to export 10kW for 98% of the time,” said Vincent.

To put it another way, intelligent flexible connection technology will allow new solar-equipped customers in the operating radius of the Sheidow Park substation, where more than 46% of households already have solar on top, to export more energy by reducing exports only when the network is actually constrained.

ARENA support

Flexible Exports “will quantify the extra value this can create for solar customers in constrained areas compared to zero-near-zero export limits, informing the business case for DNSPs to invest in this capability,” said the Australian Renewable Energy Agency (ARENA), when the project was announced in July.

ARENA is supporting the AUD 4.84 million ($3.6 million) project with AUD 2.08 million in funding. It said it aims to verify a system that can give customers “greater choice, the ability to export more from their solar panels, access to cheaper energy, and improved security and quality of supply – all without costly network upgrades.”

Participation is not mandatory. Those in the shadow of Sheidow Park substation who would prefer to use other inverter brands will still be connected, but with a 1.5 kW export limit, because on a few occasions each year – typically on mild-sunny days in spring, when solar is pumping around the middle of the day, and the demand of air conditioners has not yet cut in – the system can no longer cope with more exports at even 5 kW.

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Existing customers and those upgrading in other parts of the network that aren’t congested are not affected by the Flexible Exports Trial, and will continue to be able to export up to 5 kW.

As the trial begins, Fronius and SMA inverter providers in Australia are simultaneously working to provide inverters with built-in capability to manage flexible exports, such that they won’t require the mediation of the Droplet tech. And the range of Droplet-compatible inverter systems will also be expanded over time.

The specially enabled inverters will automatically adjust their export limits every five minutes in response to locational, dynamic limit signals issued by SAPN, the distribution network service provider (DNSP).

“We expect that once we have proven the technology and assessed the customer experience that this will become a standard offer for new solar customers in South Australia from mid-2022,” Vincent said. “It is part of our plan to double the amount of solar that we can accommodate on our network by 2025.”

New tech

SAPN was instrumental in proposing what has become a controversial rule change by the Australian Electricity Market Operator, which, in brief, will allow networks to apply to upgrade the distribution network — whether with innovative fixes such as the dynamic exports being trialed in this project, or with physical upgrades to the system — to support greater solar integration, and charge solar customers a tariff for those upgrades.

In an interview with pv magazine Australia in June, Bryn Williams – network strategy manager at SAPN – said the rule change would support changes to the ability of the network to host more distributed renewable energy.

“In the future, we can consider pricing arrangements that pass on the component of our costs associated with enabling more energy to be fed in, to the people who are using that, separate to charging for simply maintaining the network etc which will continue to be recovered through the normal charges on energy consumed from the grid,” he said.

Energy Networks Australia, the industry body representing gas and electricity distribution and electricity transmission networks, welcomed the commencement of the 12-month trial.

ENA Chief Executive Andrew Dillon said he believes “the SA trial will have implications not only for the rest of Australia, but internationally.”

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Source: pv magazine