The tools consumers need to claim back some power from the incumbent utilities are already available, says Reposit Power chief technology officer Lachlan Blackhall, but when they are adopted at scale all energy users will notice the effects.

Reposit’s box of magic software is connected to a customer’s switchboard when a battery is installed. Onsite meter data is linked via the cloud with data from weather forecasters.

The software learns from the household’s consumption as it goes and then thinks ahead to match the next day’s predicted load with expected solar generation based on the weather outlook. If tomorrow’s forecast is for a curtain of cloud, the system may decide to recharge overnight on off-peak grid power.

The result is maximised self-consumption and a minimised bill.

“The algorithms underlying it ensure we have very accurate predictions all day every day,” Blackhall says. “We’re able to plan what the battery will do throughout the day and then control it in real time to ensure the customer is getting the value they expect from their battery.”

The Canberra-based company claims its product halves the payback period for a residential battery.


Another boost to savings comes from Reposit’s GridCredit system which allows households to sell surplus energy into the grid to an approved list of retailers, and potentially back to the network operators, when prices are highest. When Blackhall spoke to EcoGeneration Diamond Energy and Simply Energy were offering “GC100” GridCredit offerings of $1/kWh, “which is a very good deal for energy”.

“It’s important that we continue to find ways to incentivise customer participation in the grid,” he says. “GridCredits are a useful mechanism for that.” Reposit doesn’t “clip the ticket” on GridCredit payments, he says.

As consumers are more informed about the electricity market they’ll learn the value of their home storage systems. If $1/kWh sounds generous it’s because the spot price rises sharply at key points of the day, and battery owners are well positioned to sell at those times, he says. “The GridCredits are a reflection of that underlying value.”

Distribution models are in flux and no-one is certain how it will all end, but Blackhall sees a home system with solar and storage as a small part of a much larger and very flexible consumer power station. As that network of home systems grows it will have increasing relevance in the grid. He believes more residential battery systems connected to the grid will bring greater stability to it.

Under that scenario, GridCredits are an essential part of the changing generation mix. “They are definitely here to stay,” he says.

As “spinning generation” is shut down, and coal-fired plants in particular, the grid will become less stable. This will place more pressure on the ancillary services market, which will become more lucrative as renewables make up a greater share of generation. This is already the case in South Australia, he says. “Nationally, as we start to see the phase out of fossil fuel-fired generation, you would anticipate that the value you see in the stability market for South Australia actually become valuable in each of the market regions around Australia.”

There is every reason to expect GridCredits will become more lucrative as renewables make up a much greater share of the market and many more residential batteries are installed, he says.

Powershop is also on the company’s approved list, which Reposit expects to add to as it finalises relationships with other retailers and networks. It says its product will be supported anywhere on the NEM.

First charge

Blackhall founded Reposit with Dean Spaccavento in 2013. The pair met in 2008 and in 2011 decided they both “shared a vision” about renewable energy and why it deserved prominence. The two started working on a prototype and five years later are offering a second generation technology and have employed 15 colleagues. The first system was installed in March 2015.

Hundreds of systems have been installed across Australia since then, he says, but things are expected to become far more busy as storage meets the mass market. Currently, everything is assembled at its Canberra HQ, but plans are in place to move to a much larger manufacturing base.

“We expect the amount of storage to increase pretty significantly,” Blackhall says, citing one estimate of a million batteries by 2020, “which is pretty substantial.” Reposit has partners in place to help with scaling up.

When it comes to competition on the world stage Blackhall refers to Reposit’s technology as being “reasonably” unique. “The whole world is trying to understand how battery storage can be deployed and managed in the grid,” he says. “Globally this is seen as the way we will need to go to ensure we can support a large installed base of storage. It’s important to get it right in Australia.”

Battery suppliers are looking at Australia as a mature market, he says. “This is the kind of solution we’re going to need everywhere [globally] to ensure we have high penetration of renewables while ensuring we have reliable, cost-effective grids into the future.”

The Reposit software can be integrated with a limited list of battery and inverter manufacturers, but options will be expanded. “Our view is that customers should be able to use the battery system that they want.”

Of course, there is always the chance an ambitious customer might choose to install a mighty system (or cut his consumption dramatically) and become a net seller of electricity. Blackhall says it’s unlikely, but not impossible. “If the incentive is there to do that then it might be an entirely rational thing for them to do.”