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Battery basics and the wholesale energy connection

Australian energy storage company RedEarth wants to open up value in batteries by guiding its customers to where the revenue is to be found.

There is a lot of fancy talk about what batteries can do, if you listen to engineers who are excited about their potential to provide services to the grid and firm generation from utility-scale wind and solar plants. At home, however, it’s best to keep things simple – charge a battery on solar during the day and use that energy at night.

That’s the start of a solid relationship with a battery, says RedEarth Energy Storage chief technology officer Chris Winter. If they want to take it further, owners will need to twig to the importance of aligning consumption and technology with the right retail offering.

Let’s say a household is signed up to a deal that gives them wholesale pricing, he says, citing retailer Amber (the only one offering such an arrangement, to EcoGeneration’s knowledge). “Wholesale pricing protects you from the downside but also gives you the opportunity to feed into the grid when the price is quite high, so you can energy-trade and make some money like that,” Winter says. “And when there is negative pricing you can get paid to charge your car.”

Winter has personal experience of taking profits. When a turbine exploded at the Callide coal plant in Queensland in May, prices immediately rose. Winter received a text from Amber suggesting he switch off large loads. As the owner of 30kWh of battery storage (and no rooftop solar) he took the opportunity and discharged, although it wasn’t a strategy he could keep up every day. He also profited from Amber’s hedging position, where the retailer shared the payoff of a cap contract that was suddenly in the money. “I have to admit, it’s been quite good,” says Winter, pictured at right above with RedEarth co-founder and CEO Charlie Walker.

Braun and brains

Brisbane-based RedEarth started out in 2013 making integrated battery systems (that include an inverter, so they can be simply connected with existing solar). The range has grown and evolved since then, but the overall offering is pretty much unchanged: modular storage, ready to use on- or off-grid.

It’s all very well selling the hardware that can free customers from opaque relationships with energy providers but the ambition is to provide them with the smarts as well.

The company monitors most installed systems that are within coverage range, but instead of running a virtual power plant where it commands those assets RedEarth offers its “Personal Power Plant” model, where operation is part-manual and part-automated.

“We’re not trying to get the perfect result, but we get a very good result for customers,” Winter says. “You can generate more revenue than you are spending on the electricity you are using. That’s where we are trying to get to.”

Winter hints that RedEarth is working on “a few other ways” customers can access revenue streams. “We’re still finalising those.”

The reason for owning a battery is to fill up during the day on free solar and use that energy at night, when the energy price is higher. If you can make it through the night on stored energy, that’s great; if you’re on a wholesale plan and you run out of charge at 3am, say, the grid energy you need will be cheap.

Off-grid homes

Perfect conditions for residential solar, but will any be saved for when the sun goes down?

Winter designed RedEarth’s BlackMax Power System, available from 3.3 to 12kWh, for off-grid systems, expecting it would be put to use in sheds or small applications. “Then people started using them for running their homes,” he says. “I didn’t realise there were so many homes running off truck batteries. We had to increase the size. Now it’s one of our most popular products.”

The system, which comes with PV panels, is the only Australian-made off-grid system to have made the Clean Energy Council’s approved products list. The company’s other off-grid solutions include the Honey Badger, up to 26.4kWh, and the Drop Bear, up to 65kWh.

Sizing storage for a low-load, off-grid application takes finesse. If you run out of power, you’re left in the dark. Many owners will reply on a small diesel generator, perhaps, “but if they’re careful – not running air-con and so on – [storage] works really well”.

The company uses lithium iron phosphate (or “LFP”) cells, which Winter says last a lot longer if charged and discharged over four hours, for example, than one hour. RedEarth’s Troppo battery comes with a 63-amp breaker, for 3kW capacity. “If you put a 5kW load on there after a short time that breaker is going to trip to protect everything,” he says. “You shouldn’t be running a battery that hard anyway. Just put a second battery in.”

Cells are sourced from manufacturers in China and there have been discussions with an operation looking to start out of Western Australia.

RedEarth is not likely to switch to lithium-manganese-cobalt-oxide, or “NMC” technology, he says. Yes, the chemistry delivers higher energy density, but there have been fires. “It’s a big difference between different chemistries,” he says. “But in my mind I’m not going to use any other chemistry [but LFP]. There is just no point.”

Business appointments

Some clients have asked for very sizable energy storage solutions.

As the world gets wise to the flexibility and value in clean energy solutions, enquiries are coming from all quarters. Business and industry are keen to cut costs and decarbonise their operations but it’s not so easy to deliver storage solutions that look like good value, he says. “With the business case you’re still just a couple of years off on the return on investment.”

In the meantime, yes, some business owners are committing to storage where it makes sense. Winter hints he is working on solutions that will shorten payback periods for C&I solar-and-storage solutions. “We’re think we’re going to crack [return on investment for C&I systems], which will open up quite a bit of opportunity for us.”

RedEarth has three patents in place, associated with energy management software, and it is working on greater ambitions. The company has turned out about a thousand systems since kicking off in 2013, at around 10kWh per system.

“I see us as a bit like Apple,” says Winter, who also co-founded zinc-bromide flow battery maker RedFlow. “Apple is a hardware company; they make phones and sell them. But now they have a recurring revenue stream based on their hardware.”

As RedEarth backs up its energy solutions with automated and personalised directions on how to profit from storage, it hopes to increase its worth.

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