Rooftop solar cap? Network suggests limit to regional PV installs

Not everyone can install solar PV on their roof: renters and people who live in apartments, for example, or home owners with overshadowed roofs. But what if you couldn’t install solar on your roof because there was too much installed PV capacity on your local grid already?

The potential for that exact scenario to happen was raised this week by Powercor’s Lara Olsen, a speaker at the All-Energy Australia conference in Melbourne on Wednesday.

Olsen, who is manager of Future Network Technologies at CitiPower and Powercor, said the Victorian network operator was in the process of launching a revised online pre-approval process for customers wanting to install solar.

The new program, said Olsen, means “small customers will know straight away if they can connect solar or if there is too much solar in that area and we need to find another solution.”

What this other solution might be, Olsen didn’t say, but Powercor is working on sorting that part out. The utility, which services outer western Melbourne and rural Victoria, is participating in a interstate trial led by the University of Technology in Sydney that has the broad aim improving the economics of local energy generation for Australian consumers.

The project’s focus is to trial Virtual Net Metering and Local Network Charges, which it is doing at five sites in Victoria, NSW and Queensland, supported by $250,000 funding from the Australian Renewable Energy Agency (ARENA). The trials will test how these work and the best and fairest way of calculating them.

For Powercor to be making provisions for an overload of distributed solar is an interesting move, though, for a network that, at this stage, has just a 13.4 per cent penetration of rooftop PV – about half the penetration of Energex, in Queensland, and of the networks in South Australia and WA.

Powercor is planning ahead in other ways, too, trialling the role of grid battery storage in smoothing supply and deferring the need for costly infrastructure upgrades.

In July, it announced plans to install one of Australia’s largest battery storage systems on its regional grid in Buninyong, south of Ballarat.

The 2MWh lithium-ion battery – which is currently being built in South Korea by Kokam – will be housed in 40 foot shipping container and will be capable of providing approximately 3,000 customers with an hour of back-up power during an electricity outage.

According to Powercor’s head of strategy and business development, Charles Rattray, the trial – which should start in December 2015 and be fully operational by early 2016 – is part of the company’s effort to accommodate for an increasing amount of distributed renewables, and to encourage the energy choices of its residential and commercial customers.

“We see our network as the backbone of the future energy system,” Rattray told RE in an interview in July. “Not everyone can add solar to their roof. We see our role…as to share those (renewable) resources across the grid …which is what a network does so well.”

It’s also about sharing the referred costs of this distributed energy, too. Back at the All-Energy Australia conference on Wednesday, UTS project director Jay Rutovitz warns of “a potential situation where there is an increase in costs for those who are left (on the grid), who are not self-generators.”

Olsen refers to this a cost “smear”, and says one of the network’s major tasks at the moment is to work out, how do we make it fair “for all of our customers”?

“In the long-term, there should be a saving for all customers. A right-sized network… should result in lower prices for consumers,” she said.