Deploying battery-powered renewable energy

Pulau Ubin, population 38, is a tiny car-free island in the waters off mainland Singapore. Known for its natural beauty, boardwalks and traditional wooden kampong houses, there are no skyscrapers or ATMs here. While the island offers a glimpse of a previous era, its power infrastructure hints at progress. In 2023 the island’s microgrid was finally greenified – diesel power phased out, solar panels installed. What has really made this transition viable is the battery technology that supports it.

The island’s microgrid upgrade was among the first on-the-ground projects for VFlowTech, a Singapore based startup founded in 2018. Co-founded by Dr Avishek Kumar, who has a background in solar, and Dr Arjun Bhattarai, a materials scientist, the company emerged to develop innovative solutions for one of the biggest challenges for renewable energy; how to store it. Their flagship product is the PowerCube, a low-cost, modular, vanadium redox flow battery – an alternative to lithium-ion batteries that uses vanadium ions to carry charge, and has a life cycle of up to 20 years. For the past seven years VFlowTech has secured over $16 million of investment, growing to a team of more than 80 people. It is on a mission to support wider access to clean energy.

Clean energy – drawn from renewables – depends on batteries in order to mitigate the peaks and troughs that are inherent to it. Solar panels, for example, collect energy all day but most of this needs to be discharged at night. Huge amounts of energy need to be stored for long periods, ideally with batteries that have the potential to supply power to a town or city – potentially for days at a time. Kumar runs through the existing battery technology, which all have technical gaps. High energy density Lithium-Ion energy storage systems, which are commonplace in phones and laptops, are prone to a phenomenon called thermal runaway. “Use your phone for 30 minutes and it’s fine,” says Kumar. “Use it for an hour and it gets hot.” Lead-acid batteries and supercapacitors also fail to meet the demands for renewable energy, and degrade too rapidly.

Vanadium flow batteries, which have limitless capacity and long lifespans, are the most suited to grid scale stationary energy storage. Even these have inefficiencies, though. Research by Bhattarai has helped VFlowTech bring to the market a new generation of flow battery, which has a 25 per cent higher energy density and a lower parasitic loss. VFlow’s PowerCube battery fits in a shipping container. It is modular and stackable, conducive to providing storage for remote settings and microgrids, such as in Pulau Ubin. Innovating in this space is not a fast process – it has taken seven years of research for VFlowTech – but by deploying the batteries in real-world settings across seven countries, Kumar says that the company has been able to react and respond to feedback from customers: “Like fixing a plane while flying it”.

Demand for this technology is high, the market fertile. According to the International Energy Agency (IEA), battery deployment in the power sector more than doubled in 2023, adding a total of 42GW to electricity systems around the world. Yet for the world to meet its climate and energy targets by 2030, there needs to be a sixfold increase in storage. Much of the research and investment in new technology, says Kumar, has been in China. “I found out that we can fill this gap and bring vanadium redox flow battery technology outside China, and meet the local demand. So that’s the reason we set [the company] up.”

VFlowTech is responsive to three customer segments: utility companies, remote islands and the various players in renewable energy intellectual property. As the race to net zero continues, Kumar says there is no shortage of inbound inquiries. The PowerCube has been trialled for use with electric vehicle charging points in Perth, Australia; purchased by a Japanese multinational as an energy backup resource for natural disasters; and is set to power Jurong Island, an industrialised location in Singapore.

His business, however, is not dependent on securing hundreds of customers. “I only need five or six to take us to an order value of a few billion dollars,” says Kumar. Right now, VFlowTech is doing its series A2 funding round and is looking to raise $20m. Within the next five years he hopes to grow this to $800m. Scaling will require leveraging vendors and innovation on new materials in order to reduce costs. But the path, he says, is quite clear: “I don’t need to convince my customers, just build trust with them.” Seeing the Pulau Ubin project whir into action has spurred him on. As well as a vast drop in airborne emissions, it has reduced its annual diesel consumption by 100,000 litres. “The whole island is powered by a battery. These are proud moments for us.”