Time of use tariffs can shift EV charging away from peak periods

The Australian Renewable Energy Agency (ARENA) and energy retailer AGL have published the results of their Electric Vehicle Orchestration Trial, finding that time of use tariffs can play an immediate role in moving charging to off-peak periods.

The $8 million trial got underway in early 2022 with the installation of 200 EV smart chargers in homes across New South Wales, Queensland, Victoria, and South Australia.

The purpose of the trial was to better understand the interplay between customer EV charging and the impact on the grid at peak times.

The project was based on the assumption that there will be 2.2 million EVs in the National Electricity Market by 2034-35, and this increased uptake of EVs has the potential to be a significant challenge for the electricity supply system if it's not managed carefully.

Nearly 20 months later, AGL and ARENA have unveiled the results of the Trial, and it’s a mixture of good news, surprising news, and less-than-good news.

The surprising news was that the overall residential EV charging load was smaller and more diverse than had been expected. In fact, according to the findings, only 16% of home chargers were used every day, and the “expected early evening peak in charging load is absent from the baseline data.”

Unsurprising was the fact that most residential charging takes place overnight, particularly on weekdays, but the good news from the trial was that EV customers who were offered time-of-use tariffs have already begun moving their charging to off-peak periods.

‍

Subsequently, AGL found that such EV charging orchestration is effective in reducing demand at peak times, particularly during the evening system peak.

Similarly, customers are reportedly “receptive” to having their charging controlled, provided that they have the option to opt-out, even though the opt-outs are “rarely used”, according to AGL.

It is therefore unsurprising that 84% of customers who participated in the trial would be likely to sign up to a smart charging service.

The only less-than-good news was that, according to AGL, “the state of readiness of [vehicle-to-grid (V2G)] technology during the project timeframe was such that the V2G stream of the trial could not achieve its objectives and could not be executed as proposed.”

This lead AGL to conclude that V2G technology “is at least two to three years away from being a practical reality.”

Bruce Hardy, AGL general manager for emerging business, said the electrification of transport is a key requirement on the path to net zero.

“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,” he said.

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