How many Teslas does it take to black out an apartment block? | RenewEconomy

How many Teslas does it take to black out an apartment block?

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City of Sydney backs study by local start-up, Wattblock, into how Australia’s apartment buildings will accommodate – and power – mass EV uptake.

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One Step Off The Grid

While Australia’s slow uptake of electric vehicles is a source of great frustration to some, to others, like the nation’s owners and builders of apartment blocks, it offers precious time to work through some of the more thorny problems that are expected to arise out of mass EV uptake.

Problems such as: Who pays for the electricity used to charge an EV in an apartment building carpark? How do you bill it? How much will it cost apartment dwellers to charge their EVs at home? Where should EV charging stations be put? What does it do to a building’s emissions profile? And how many Tesla Model S cars can be charged at one apartment block before its lifts cut out?


As it turns out, all of these questions and more are about to be addressed in a comprehensive new study by Sydney-based start-up, Wattblock, backed by grant funding from the City of Sydney and the NSW government’s innovate program.

Wattblock, which was founded through the Telstra Muru-D acceleration program, specialises in energy and solar reports for residential strata buildings.

From its headquarters at the Michael Crouch Innovation Centre at UNSW in Sydney, and at River City Labs in Brisbane, the two-and-a-half year old company has so far helped more than 1000 strata buildings across Australia to cut their energy costs through efficiency and demand management measures.

The feasibility study on electric vehicle charging, to be conducted over the next six months, will encompass 20 apartment buildings in Sydney and another 20 in south-east Queensland (in conjunction with Griffith University and Energex).

According to the company’s co-founder and director, Brent Clark, it will answer questions around EV charging that are already starting to plague apartment dwellers and bodies corporate, as the number of EV owners in apartment dense cities like the Gold Coast start to rise.

“It’s about breaking down the barriers that you’ve currently got on apartment blocks,” Clark told One Step Off The Grid in an interview on Tuesday.

“At the moment, people who live in an apartment and want to buy an EV, they’ve just got challenges in front of them.”

To illustrate this point, Clark cites the example of a relatively small strata building in Pyrmont that already houses two Model S Tesla owners.

“If one more buys a Tesla the lift will stop working,” Clark said. “A third person is not allowed to charge inside the building until they find a solution.”


Larger buildings can charge more vehicles, he notes, “but basically no apartment block (in Australia) has the capacity to charge multiple EVs,” despite this very scenario being just around the corner, with cheaper EV models like the new Nissan Leaf and the Tesla Model 3 set to hit the market.

And it’s already happening elsewhere in the world. In San Francisco, for example, Clark talks about a building, The Lumina, that was marketed off the plan as having 25 apartments that would come with EV recharging.

“They got flooded with EV owners, and they’ve now 45 EVs in that complex,” he said.

In terms of load, Clark says, the electricity required to charge an EV is like adding another apartment into the block.

“What you want if you are a strata builder is you want to defer the upgrade of your main switchboard at all costs, because that is a huge capital expense,” he said.

“It is also costly to string cabling to individual car spots in the car park,” he added. “So body corporates should look at running higher amp cabling in the car park, and the apartment owners can pay for the final connection, if they need it.”

But the cost and management of electricity supply are not the only problems facing apartment builders and owners.

“Some initial some initial buildings that tried putting (communal) car chargers in a busy car parking place have also run into trouble.

“Ultimately, you’ve got to pass a by-law to limit the number of hours that any one vehicle can stay on a charger.”

Among the solutions Wattblock expects to canvass to address these problems are better planning in new buildings, and in pre-existing apartment blocks, the use of demand management, solar, battery storage, and energy efficiency to make more car-charging capacity available.

“At what point could we implement a power management solution that might be able to increase by a power of 10 the number of EVs being able to be charged at the building without overloading the main switchboard?” Clark says.

“Do we have strata buildings with designated spots for car-share car parking that are not being used, that could that be adapted to be an EV charge station?

“And if you have a precinct, a number of strata plans together, would they be interested in investing in a supercharging station?”

The other challenges come from a carbon abatement perspective, where you’re driving up building’s emissions if you’re using coal-based power to charge the EVs.

This is where solar and batteries might come in, says Clark, or if the apartment block doesn’t have enough room for solar, purchasing green power.

According to Clark, solar and batteries are now delivering payback to a strata building within about 10 years. And it is a market with huge untapped potential for the technologies.

“Obviously, the size of the solar system would be dependent on the roof area available,” he notes,” but across Australia we estimate that strata buildings consume 10 per cent of the national grid.

“So there’s at least a billion dollar solar opportunity on strata buildings.”

That said, Clark adds that, currently, you can count on your hands the number of apartment buildings that have built-in solar and/or batteries.

Energy security is another concern: “What if there is a power outage? Is there a case there for batteries?”

The challenge right now for Wattblock, however, is to find the 40 buildings for their case studies.

“We have found five apartment blocks that have electric vehicle owners in them, but we’re looking for more,” Clark said.

Considering the fact that, as of last year, apartments were the most common dwelling being built in Australia, this should not be too hard. But time is of the essence.

Any interested buildings in the City of Sydney can register here. South East Queensland strata buildings can register here.

This article was originally published on RenewEconomy’s sister site, One Step Off The Grid, which focuses on customer experience with distributed generation. To sign up to One Step’s free weekly newsletter, please click here.

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  1. Alastair Leith 3 years ago

    “At what point could we implement a power management solution that might be able to increase by a power of 10 the number of EVs being able to be charged at the building without overloading the main switchboard?” Clark says.

    Existing 2 cars in example cited to power of ten is 1024 cars for a 4 apartment block.

    Ten cars to power of ten is 10 trillion 🙂

    Factors of ten, perhaps?

    • Catprog 3 years ago

      Unless the power of 10 was 1 or 2.

      Then it would be 2 x (10^1) or 2 x(10^2)

    • Brent Clark 3 years ago

      Yes, that is meant to read ‘factor of 10’

  2. Alastair Leith 3 years ago

    Makes a strong case for ultra-fast charging, perhaps via graphene supercapacitors like some Swedish and Chinese buses already use at each bus stop. You’d need serious storage though to hold all that change and deliver it in minutes not hours. One day.

    • MorinMoss 3 years ago

      It makes an even stronger case for battery swap stations

      • Alastair Leith 3 years ago

        What was the name of Shai Agasi’s company, Better Place? He couldn’t get car companies to standardise around a product.

        • MorinMoss 3 years ago

          So what? He was also promoting EVs. Are you going to claim EVs are a failure because Agassi – and Fisker – went bankrupt?
          Even good ideas can be implemented badly or too soon and when it’s cash intensive, it’s ripe for failure.
          Better Place had stations before they sold any cars – and the one car that Renault agreed to build was rather bland.
          Tesla already has the customer base and so will the established automakers once they manage to get their cars off the drawing board & into showrooms.

          • Alastair Leith 3 years ago

            So what is that’s it a huge (impossible?) commercial challenge to get car companies to standardise on a battery, it’s more than half the value of the cost of making the car. Have you seen a Tesla 3 or Tesla X chassis? Tell me how they will drop that load? And these chassis are the standard for their future vans and minibus concepts for the next decade, by which time EV market will be well on the way to overtaking ICE market.

            It’s a nice perfect world idea, I’ll grant you that, I was very taken with the whole Better Place vision. But commercial realities bumped into Agassi’s vision and chutzpah.



          • MorinMoss 3 years ago

            Tesla has already demonstrated battery swap, in under 5 min.
            There’s no need to standardize on a single battery type but since many automakers share platforms, having a few common battery formats that fits multiple cars isn’t as difficult as it sounds.
            You can always find a reason why something can’t be done; just don’t get in the way of whoever’s doing it.
            I’m sure there were many cogent arguments that early cars were just toys but horse-drawn wagons were here to stay and long trips would be done by train.
            Go tell the upstanding gentlemen of 1908 that the Wright brothers’ sad little flight at Kitty Hawk would lead to new forms of warmaking within a decade and traveling distances in hours that once took weeks, even across oceans.
            Just don’t expect them to take you seriously because everyone knows it’ll never happen…..right?

          • Alastair Leith 3 years ago

            Do you have a link for the Tesla battery swap tech? They’d have patents on it for sure if it exists.

            According to this it looks smaller than the full battery profile in Tesla 3 and X as shown above and elsewhere.

            please enough with the luddite ad hom, I’m in agreement with Tony Seba about the EV transition: Just saying the car industry is not one that works together by an large, and has resisted EVs actively todate.

          • Chris Schneider 3 years ago
          • Alastair Leith 3 years ago

            pretty cool.

          • MorinMoss 3 years ago

            Seriously? It’s too much trouble for you to google “Tesla battery swap”?

          • Alastair Leith 3 years ago

            The links I found say it’s gone on the backburner. I recall seeing this now, but are all Teslas able to be swapped in this way if the stations are build or is it a special mod to the cars?

          • MorinMoss 3 years ago

            All Model S were built with that capability; I’m not aware that Tesla has changed that but I don’t know if the Model 3 has that capability.
            EV proliferation will make it a requirement unless a pourable / pumpable electrolyte system is developed – I think MIT was working on something similar.
            When & if we get to 10s of millions of EVs on the roads in a single country, quick-charging is going to be prohibitive.
            CA has about 25 million cars – if only 4% try to quick-charge at 150 kW the demand will INCREASE by 150 GW!!
            And that rate of charge would have to be maintained for ~20 min to get a 1/2 – 2/3 “fillup”
            Current summer peak is between 55-60 GW for the entire state.

          • Michael Dufty 3 years ago

            But it is very rare to need a quick charge, it is only needed when your daily distance is greater than the car’s range, otherwise you just charge at a low rate overnight. I recall Tesla not pursuing the battery swap because it didn’t offer much benefit over supercharging in practical use. I’d imagine cars parked in apartments are even less likely than the average to use a lot of electricity in a single day, so slow charging to dedicated parking bays for every car is going to be a lot more useful than a limited number of faster chargers.

          • Alastair Leith 3 years ago

            I know it’s astonishingly big numbers if we assume the transition to EV happens like many of us assume over next 10-15 years. I never got how people assumed that EVs would serve only to stabilize the grid by adding storage, as if charging them (mostly at night at home and carparks during day) and keeping them charged for availability wasn’t going to be a key concern for owner/operators of them. Some say private ownership of cars will diminish as EVs and autonomous vehicles take over, and people will ride not drive a lot more than they do today, then charging times become even more important you’d think unless surplus vehicles are maintained just for spares.

            Good time to be a chemical engineer designing batteries and superconductors I guess.

          • Alastair Leith 3 years ago

            Tesla or Apple has patents on dual battery system software too. But perhaps the ever increasing range of new Lithium Ion chemistries will make that redundant. Metal air range extender batteries was one suggestion.

          • MorinMoss 3 years ago

            Yes and there’s also Phinergy who demonstrated what they called an aluminum-air battery driving a car several years ago.
            But the Phinergy product is more like a fuel cell and turning the Aluminium oxide back to metal would require a lot of electricity.

  3. George Darroch 3 years ago

    This problem is pretty similar to the one that shared premises had at the start of the internet age, where there as a single pipe for bits and bytes and consumption was rivalrous.

    Eventually, the provision of adequate access became a necessity rather than an extra, and both residential and commercial premises are essentially unleasable without an acceptable internet connection.

    We’ll reach a similar point with electric vehicle provision, but it might also take the next decade or two to get there. Networks will also need to upgrade in places to facilitate this huge shift in transport power.

  4. trackdaze 3 years ago

    In terms of load most of the solution can be achieved by charging overnight. At other times a priority charging schedule can be put in place.

  5. Chris Schneider 3 years ago

    This would be one of the easiest things to fix. Chargers should be required to have Modbus connections to allow the charge limit to vary depending on the requirements of the building. a very simple BMS that is connected to the site meter could then manage the charging. You could do a lot more complex things after that but at a basic level this would solve the whole issue. It would be great if they could also reverse the charge during peak periods to decrease the load on the grid at peak times.

    If everyone simply cooperated Electric cars could be the best thing that ever happen to the energy gird!

  6. jamcl3 3 years ago

    Many EVSE suppliers (including Tesla) offer charging stations that

    can share one power feed among up to four cars, and limit the total power at any instant to that of one car. This is usually enough for overnight charging.

    Some energy management systems for workplace charging will manage the total power for dozens of vehicles. Most EVs drivers can get by without about the same peak power as a microwave oven if they are plugged in long enough. If your commute is more than about 50 miles, then you need higher power but that is relatively rare.

    Therefore I see these concerns as mostly being solved already, these people are just not aware of the available technology. Here is one example:


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