Behind-The-Meter Grid Augmentation: The Missing Piece Of The Fast Electric Charging Puzzle

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I have a friend who builds electric charging networks and drives a Leaf. I, on the other hand, established an EV-centric website and drive a plug-in hybrid. Consequently, we’ve been talking for some time about how electric cars and renewable energy are going to take over the world. What will it look like and how it will happen? Given we are both people that have a very definite view of the future, we get on surprisingly well.

An issue we often canvas is how households and industry have actively taken up solar. In Australia, we now have over 16 gigawatts of rooftop PV, more than double that of utility-scale plants. This is partly because systems under 100 kilowatts are able to deem renewable energy certificates upfront and partly because behind-the-meter PV offsets both energy & transmission charges. Overall, it’s a powerful business case. 

The movement started with residential buildings, but as anyone who works in the industry will tell you, commercial and industrial clients are installing systems from 30 kW to 3 MW. A large motivator was the frustration of waiting for the government to “do something” and once the commercial business case became widely known, industry installs took on a life of their own. Industry stopped waiting. 

We now seem to be with EV charging at the same place we were with rooftop PV a decade ago. There is strong community support for electric vehicles, but also a desire to see more charging stations to encourage uptake. It’s a classic chicken and egg question, but governments are listening, and the rollout of EV chargers of all sizes continues to gather pace. 

  • ARENA is supporting a rollout of over 400 fast chargers with $24 million through its Future Fuels Program.
  • NSW will open its first funding round of $35 million to support ultra-fast charger deployment > 150 kW on 2 February 2022 as part of its electric vehicle strategy.
  • WA has committed to the “world’s longest fast-charging network” of 45 stations by the beginning of 2024.
  • SA will invest $13.1 million to leverage private investment in charging infrastructure with an announcement of successful applicants expected shortly.
  • Queensland has rolled out 31 fast chargers in its electric superhighway project and phase 3 will deploy a further 18 in regional locations.
  • Victoria has funded $ 5 million for 141 destination chargers from 11 to 50 kW.
  • Tasmania supported 14 fast chargers in 2021 through its electric vehicle Chargesmart program.
  • ACT has a 50 Chargers program with expressions in interest closing on 8 February 2022 with an allocation of $1.3 million.
  • The Northern Territory has a strategy that includes grants for EV charging infrastructure although the details or quantum of funding have not been announced. 

A recurring holdup for projects is the cost and lead time for grid upgrades to allow fast chargers to be installed. It’s the classic Catch-22. You pay the network provider to upgrade your grid connection. There is a long lead time, they own it, and then you get hit with higher charges because you have a higher peak demand. It’s a rather unattractive proposition all round. 

Solving this problem reminds me of the story of the traveler who asks a local in the town where he staying for directions for his next destination. “Oh, I wouldn’t start from here,” is the answer. Same energy. 

Until now, alternative solutions were about managing the existing circumstances. One option is software that monitors the load, and if that exceeds a set value, back off the chargers so that the load matches the maximum supply from the grid. This works really well if you are managing a fleet of low-powered overnight chargers, but it’s not a solution to deliver on-demand high-speed charging. Another solution is to install batteries to provide peak capacity, but generally, these are not able to meet the rapid power ramping requirements of EVs charging on fast chargers. While this can be ameliorated with software, it detracts from the user experience and increases the risk of outages.

An emerging alternative is behind-the-meter grid augmentation. This entails an upgrade behind-the-meter, which acts as though the network supply has increased. The network thinks nothing has changed and the charging unit is able to instantaneously draw to its maximum demand. In reality, there is a sophisticated control unit with attached battery sitting in the middle providing the service. 

An example is the ChargeCache from PowerTec in Australia. These are out-of-the-box units in 3 sizes, servicing from 50 to 750 kW charging sites. As shown below, when an EV starts a charging session, any demand over the network limit is provided instantaneously by the unit. The ChargeCache also keeps other technical parameters of the grid, such as the voltage, in balance. Between EV charges, the unit draws power from the grid to top up the battery. 

Installing a ChargeCache increases resilience by permitting seamless off-grid operation including black start, avoids demand charges by peak lopping, and allows the site to participate in the provision of network ancillary services and energy arbitrage. Your EV charge station fleet becomes a virtual power plant. While behind-the-meter grid augmentation is generally more expensive than a network upgrade, you own it and the site can capture more of the value stack. 

To return to the early observation about the uptake of solar PV, industry has clearly stopped waiting for someone else to “do something” and is now actively pursuing new charging sites and business models to support the investment. As someone said to me the other day, it’s a land-grab. With that mindset, I don’t think they are going to be waiting in the queue for network upgrades either. 

By David Mitchell, founder of and a business development advisor to PowerTec. 

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