Betting on Flow Batteries: A Conversation with Dr. Umesh and Dr. Shanmuga of Tharam- Thiran Energy Flow
I had the pleasure of speaking with Dr. Umesh and Dr. Shanmuga, co-founders of Tharam Thiran Energy Flow, a company developing Sulphur Iron flow batteries. Flow batteries have been around for a while but haven’t seen the same commercial success as Lithium-ion batteries. But Dr. Umesh and Dr. Shanmuga believe the future is bright for this technology, and I wanted to find out why.
The Name, The Partnership, and The Journey
I asked them about their company name—Tharam Thiran Energy Flow.
“Tharam means quality, and Thiran means power,” Dr. Shanmuga explained. “Our goal is to provide high-quality power through green energy solutions.”
The duo met in 2011 during their master’s program at Indian Institute of Technology, Design and Manufacturing (IIITDM) Kanchipuram. While Shanmuga pursued his PhD there, Umesh completed his at IIT Madras. During the COVID-19 lockdown, they explored the potential of flow batteries, introduced to them by their professor, Dr. Raja.
“Shanmuga explored the market while I focused on the technical aspects,” Umesh added.
They secured a ₹10 lakh DST-Prayas grant, packed their bags, and started building their first prototype.
What Makes Flow Batteries Different?
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I asked Umesh to break down how flow batteries differ from lithium-ion ones.
“In a lithium-ion battery, the electrolyte is solid and stored in the same compartment as the reaction. That limits storage capacity,” he explained. “But in a flow battery, the electrolyte is liquid and stored separately, so we can scale up storage simply by increasing tank size.”
“So it’s like having an external fuel tank?” I asked.
“Exactly! And no fire hazards—unlike lithium-ion batteries, flow batteries don’t catch fire,” Umesh added.
Choosing Sulphur-Iron chemistry
I was curious why flow batteries hadn’t taken off commercially.
“The most common chemistry uses vanadium, which is rare and expensive,” Umesh said. “Other chemistries, like zinc-bromine, have issues like metal deposition.”
“That’s why we chose sulphur-iron,” Shanmuga added. “Both materials are abundant, cheaper, and still allow for energy and power decoupling.”
Challenges and the Road Ahead
Of course, I wanted to know what challenges they faced.
“A big one is preventing crossover—where Sulphur moves between sides and affects performance,” Umesh said. “We’re also working on improving power density since Sulphur-based batteries have slower electrochemical reactions.”
Their first prototype was 1 watt. Now, they’re scaling up to 1 kilowatt, with plans for a 5–10-kilowatt system in the next two years.
The Future of Flow Batteries
I asked how they see their batteries competing with lithium-ion ones.
“Flow batteries are ideal for stationary applications where space isn’t a constraint—like microgrids, solar farms, and telecom towers,” Shanmuga explained. “Lithium-ion works for short-term storage, but for 10, 20, or even 100-hour storage, flow batteries make more sense.”
Umesh added, “We’re thinking beyond standard battery setups. Why not integrate them into buildings? Imagine an entire structure dedicated to energy storage.”
So, what’s next?
“In the next 18-24 months, we’ll test our 5-10 kW pilot systems and refine our chemistry for large-scale deployment,” Umesh said. “But innovation won’t stop. We want to keep pushing energy storage forward.”
It’s clear Dharam Theran Energy Flow is on an exciting path. I can’t wait to see where they take this next!
By Bharti Krishnan
