Utilities move to kick rooftop solar off the grid

Utilities in Queensland are looking to limit and even stop households exporting excess electricity back into the grid from their rooftop solar panels, in a move that other Australian network operators are expected to follow – even if it does have the potential to accelerate grid defections and the so called “death spiral”.

New standards are expected to come into effect in Queensland’s Ergon and Energex networks next week – and become a fixed ruling from next January – that formalise a practice that has been going on for months.

Essentially, any rooftop solar system under 30kW will gain automatic approval from the networks, as long as it has equipment installed that can prevent it from exporting electricity back into the grid.

The move is being introduced by networks in the name of grid stability – excess rooftop solar power in some feeders is getting to the point where it is creating reverse flows. The operators complain of oversupply and power spikes.

It has already been standard practice for networks to require large systems of more than 30kW to have export limiters to avoid what they call the “Christmas Day” effect – when large amounts of solar electricity are fed back into the grid when there is no demand.

This practice has largely gone on without controversy, because most commercial and industrial users are looking to consume most of their output anyway, a practice that is now extending to homes.

But the initiative also risks creating a new mindset among households and businesses for “self consumption”, and potentially, once battery storage costs fall far enough, to disconnect from the grid.

The average home consumers less than half the output of an average 4kW solar system – but since the tariffs paid for excess electricity have fallen so sharply, and in many areas are voluntary – households and businesses are now motivated to consume all the output on the premises.

That is encouraging households to look at battery storage, for use at night or on days with little sun. Ultimately, it may encourage households to look after their own needs and disconnect. Advocates such as Energy for the People say this could be attractive for some communities now. Even investment bank UBS has said it could be economically attractive for the average household in Sydney and Melbourne to disconnect from the grid by 2018.

The initiative has encouraged companies such as Queensland-based Renewable Energy Solutions Australia to introduce products such as VoltLogic,an inverter system that can limit power exported to the grid from solar systems, and which can be integrated with battery systems. It can restrict the amount exported, although its standard function is zero export.

RESA development manager Michael Le Messurier says in many ways it is a good outcome. Rural customers on “thin, weak” lines in Ergon’s network, for instance, were being told they could only put 1kW or 2W of rooftop solar when they were looking to install 4kW, 5kW or more.

“What it does do is encourages storage,” Le Messurier said. “There is a lot of interest in that, and one of the benefits of storage is that it reduces the upgrade costs of networks down the track.”

That appears to be a deliberate ploy by Ergon, which itself has recognized that it may be more cost effective for both it and its consumers to encourage customers to invest in renewables and storage, rather than rely on the expensive delivery of centralized fossil fuel generation along thousands of kilometers of poles and wires.

In more populated areas, however, it will be interesting to see how this plays out. Network operators see their future in facilitating micro grids and the like, but providing consumers with the economic and technology incentive to disconnect could be counter-productive.

“More and more cases are arising where customers are looking to install solar, and only when they put the application in are these systems being knocked back to nothing,” Le Messurier said.

“In some cases, customers want to install a 15kW system but can only get approval for 1kW.”

Consumers in Victoria have also been told either that they cannot install systems, or will have to downsize the number of modules. There is anecdotal evidence this is also happening in other states.

Industry insiders say the “limiters” are essentially a means to “buy time” – a couple of years – to help networks get their minds around new business models, and new tariffs, that will allow networks to incorporate new technologies.

But others are concerned. John Grimes, from the Australian Solar Council, fears that these technologies are being potentially used as an excuse to slow down deployment of rooftop solar.

“It is not just potential changes to the renewable energy target that are putting the industry in danger. Technical barriers are also being applied inappropriately …. We are very concerned about the rise of what are basically trade protection measures.