EV charging — how to future-proof multi-residential properties

The transition to electric vehicles (EVs) is well underway, and with it, the need to provide EV chargers in multi-residential buildings. EV charging presents multiple challenges in terms of infrastructure and cost. What do developers, strata managers and architects need to know? And what can be done to future-proof new and existing assets?

Electrical engineer Toby Murdoch is an associate at Ashburner Francis and installs EV charging systems into new and old buildings. “Managing energy supply loads and measuring and allocating cost are the two key issues,” Murdoch said, adding that understanding who will be charging EVs is essential to designing a system that will meet current and future needs.

Simon White, founder of design advisory consultancy DVLP, agreed. As design manager at property developer Aria for eight years, White has seen a rapid increase in demand for EV chargers. “The majority of investor purchasers ask about EV charging now,” White said. “Every owner-occupier purchaser wants guaranteed access to a charging point.” White noted that ESG is increasingly important to institutional investors, with electrification a prerequisite for Green Star certification.

Designing for peak demand

EV chargers place additional demands on the electricity grid. It is critical to ensure that a building’s energy needs can be met during peak times, which may only be a risk a few times a year, for example when air conditioning is running in the evening. Switchboards must be designed to cope, and depending on the size of the building, transformers may be required. This can be expensive.

While it may be too costly to engineer a system just to cope during peak periods, energy loads can be managed effectively using technology. A monitor on the electrical substation can send signals to the EV chargers to decrease or increase their charging rate to ensure the total building load remains safe.

Murdoch noted that emerging technology developed in Brisbane goes one step further, using AI to tailor the charge rate for each car. “As an example, during times of high demand the system can prioritise a car that is at 20% battery charge plugged in at 5.30 pm over a car with 70% charge plugged in at the same time,” he explained.

In the future, there is also the potential for car batteries to feed power back into the grid in the same way as home solar batteries currently do. In this scenario, a car could power an office or home during the evening when solar power is not functioning.

New builds — get it right first time

With new builds, asking the right questions at the beginning of the design process is key to a future-proof system. How many people will charge how many cars, at what time of the day, and with what type of charger? Superchargers can charge a car much faster than a standard charger but require DC power, an added expense.

Murdoch warned against marketing a development as ‘EV-ready’ without first defining what that means for everyone involved. A decision needs to be made early on whether every car bay will be EV-ready and how many shared charging stations and vehicles will be available. He recommended that developers discuss the options at the beginning of the project and that architects engage electrical engineers during the DA phase to mitigate costly mistakes.

“We’ve worked on jobs where the architects haven’t factored in the required space for the switchboards and transformers, and as a result, an entire apartment has to be reclaimed,” Murdoch said. Understanding and defining what’s needed may add a couple of thousand dollars in engineering fees at the start but could save hundreds of thousands of dollars later.

The complexities of retrofitting

Retrofitting offers a different set of challenges. Murdoch said each property must be assessed on a case-by-case basis, with scale, existing infrastructure and geographic location all factors that impact the choice of solutions.

“For retrofits, we start by monitoring the existing system to measure its spare capacity. From there we can work out whether it can cope with EV charging or whether we need to upgrade the system and add a transformer,” Murdoch explained. This is also contingent on the grid in the local area having capacity, something the local energy supplier needs to advise on.

White noted that EVs are generally twice the weight of petrol cars, so in older buildings with concrete floor slabs, too many EVs may mean the slabs need to be structurally reinforced.

Who pays?

This is the question that’s top of mind for everyone. Ownership structures will determine who pays for the infrastructure, factoring in what electricity suppliers in different states are willing to contribute. In most cases, privately owned assets must pay for upgrades themselves.

Murdoch said the cost of electricity can be allocated in different ways. “In new developments of up to about eight storeys, it’s not hard to feed power down from an individual dwelling to its car bay so that the electricity cost is charged directly to the owner’s bill,” said Murdoch, who likens this to simply adding another power point. “For larger developments where this isn’t feasible, we can install metering devices that measure and charge by use.”

For a retrofit, the owners need to fund the necessary infrastructure upgrade. As the number of EVs in general use grows, properties that don’t have the capacity for EV charging will likely lose value. However, until EVs become the norm it may be hard to convince owner-occupiers to chip in. Installing communal chargers can be the best and most economical solution.

White noted that EV charging can be leveraged as a marketing tool. He said that at Aria’s ‘Upper House’, a 32-level, Koichi Takada-designed tower due to open mid-2023, an EV charger backbone has been pre-installed throughout the basement and podium parking areas. “Distribution boards and full cable tray runs on each level simplify the process for residents to add a charger to their own parking spaces,” White said. “The capital cost means the residents can add a standard charger for around 60% less than if no backbone had been installed.”

At Aria’s completed development ‘The Standard’, three Tesla Series 3 vehicles were purchased and gifted to the body corporate for communal use. “The building has since enlisted the services of Ohmie Go to manage the booking, cleaning and insurance of the common vehicles,” White said. “The communal vehicles mean a resident has less reason to have a second car, and over time, it will help to reduce the number of cars in these buildings generally.”

Stratas beware — get it in writing

Murdoch drew attention to the importance of ensuring that strata by-laws reference EV charging. For example, by-laws should clearly state if charging will be slower during peak periods and define rules around when you can charge and how charging is metered. Electrical engineers can add value by helping to draft strata by-laws.

“Clearly capturing the who, how and when of EV charging — whether for a new build or a retrofit — is enormously beneficial for everyone and can save a lot of arguments,” Murdoch said. “It’s a valuable service that engineers offer that is not widely known or leveraged.”

Murdoch concluded that with the rapid evolution of technology in EV batteries, chargers and the associated management software, regular communication with engineers is the best way for developers, strata managers and architects alike to stay informed and avoid costly mistakes.

Image caption: Upper House by Aria, designed by Koichi Takada Architects.