Strain on grid from electric vehicles smaller than expected, AGL Energy trial finds

Electric vehicle owners respond to price signals from tariffs and charge in off-peak periods, allaying concerns that Australia’s electricity grid may struggle with the rise of zero emission cars.

The strain on the country's electricity grid caused by EVs may be smaller than expected, a trial conducted by AGL Energy and the Australian Renewable Energy Agency has found — in findings that will temper concern about the capacity of infrastructure to cope with the rise of zero emission vehicles.

EV sales are rapidly growing as consumers move to capitalise on falling prices and federal and state incentives — a rise that has elevated worries that Australia’s energy grid could struggle to deal with the rise in demand for electricity for charging.

In results that will dampen some concerns, a trial of EV users conducted by AGL and ARENA said there was a smaller than anticipated bump in demand on the grid.

The expected evening charging peak around 6pm is completely absent. There is a marked increase in charging load between 9pm and 11pm,” AGL concluded.

“The increase in charging after 9pm suggests that a proportion of customers are self-managing the charging hours of their car and deferring their charging to either an actual or nominal off-peak period.”

The response of the 200 EV-owning households is a boost to the country’s transition. Australia is rapidly looking to wean from its dependency on coal, targeting having zero emission sources generate more than 80 per cent of the country’s power by the end of the decade.

Coal remains the dominant source of Australia’s electricity, generating around two-thirds of all power. But coal is under sustained economic and social pressure, and Australia’s Energy Market expects two-thirds of generators to be retired within the next decade.

The rise of renewable energy is expected to heighten economic pressure on coal generators. A rapid increase in solar generation particularly means Australian wholesale electricity prices are often below zero, meaning coal generators are often making losses throughout the day. When the sun sets, however, the wholesale price often spikes and coal generators will recoup losses and remain profitable.

But further increases in solar and a deployment of batteries will crimp the profitability of many of Australia’s coal generators.

An accelerated exit of coal generators — many of which are approaching the end of their technical lifespan — will worry some about Australia’s so-called dispatchable capacity – sources of electricity that can be relied on irrespective of the weather.

At the same time, Australia is expected to see a rise in demand as EVs become more popular and users look to recharge at home.

AGL, however, said its trial found many users respond to price signals and wait to charge when demand from households falls.

Bruce Hardy, general manager, emerging business, said the findings demonstrate the importance of incentive tariffs.

“The results of the trial indicate that time of use tariffs were effective in managing charging load and charging orchestration can help reduce charging demand at peak times, particularly during the evening peak,” Mr Hardy said.

“We will continue to incorporate these key findings when developing products and services to meet our growing EV customer base.”