As we turn more attention to renewable energy, the battery issue becomes even more critical. Generating energy is one part, but storing and using that energy is equally important. Umesh Vasu, 37, founder of Tharam-Thiran Green Energy Flow, who holds a doctorate in mechanical engineering from IIT Madras, says, “As our country moves towards net zero targets and rapidly increases its share in renewable energy, the demand for robust battery energy storage systems (BESS) has become more urgent than ever. We saw that a one-size-fits-all battery solution would be a great solution to the unique needs of a renewable-dominated grid. In particular, long-term energy storage up to 10 hours remains expensive and technologically underdeveloped in India, even as changing demand patterns and increasing renewable integration make such solutions a near-term necessity.” Indeed, there was a problem that needed a solution.
problem area
According to Umesh, “Mainstream storage technologies, such as lithium-ion batteries, are suitable for the short to medium term, but face economic and security constraints when deployed for multi-hour, large-scale grid balancing. Meanwhile, the mismatch between variable renewable generation and consumer demand grows, increasing the risks of energy outages and grid instability. These constraints are likely to hinder India’s progress unless we deploy new, affordable and scalable long-term Don’t find storage alternatives and commercialize them.”
To explore potential solutions for battery energy storage systems, Umesh returned to his alma mater, IIITDM in Kanchipuram in 2020, where he focused on various aspects of flow battery technology development, refining both the science and engineering. Umesh says, “As the project gained momentum and scale, I was privileged to bring on Kalishkumar and Vaiska as team members, uniting our complementary expertise and shared passion to pioneer this energy storage solution.”
finding solutions
According to Umesh, “Lithium iron batteries are widely used even for grid-scale energy and have cost advantages. However, it has the problem of low capacity. Lithium-iron batteries can discharge energy for a maximum of two to four hours. If one needs more hours of energy, you will have to install more batteries.
“Then we have vanadium batteries. These batteries use vanadium salts and are housed in a separate container. The more energy that is stored and discharged, the more chemistry is required. Vanadium is an expensive salt and is surrounded by a lot of geopolitical issues right now, so it is expensive. We thought, why not use a chemistry that is cheap and readily available? Why not make a battery that is cost-effective and durable Yes?”
Umesh says, “Electrolyte cost is a major component of long-term energy storage systems. Our studies have shown that vanadium, despite being proven, faces significant supply chain and cost issues. Therefore, we shifted our focus to iron-based chemistries, which offer high safety and compelling economics for large-scale energy storage.” After rigorous evaluation, he chose to work on a sulfur-iron redox flow battery. “The technology takes advantage of widely available raw materials and promises significant reductions in electrolyte costs.”
economical batteries
Umesh explains the mechanics of battery energy storage and dissipation. “In batteries, energy is stored inside the solid components of the battery – the chemicals inside the cell. So, if a battery can run a device for 1 hour, to make it run for 10 hours, you will need to add more chemicals inside the same battery body, which impacts performance.
“In contrast, a flow battery separates the chemicals from the cell. The energy is stored in liquid solutions called electrolytes, which are placed in external tanks. These liquid electrolytes are pumped through the battery cell, where chemical reactions occur to charge or discharge the energy. So, if you want to store more energy or make the battery last longer, you can increase the amount of liquid chemicals in the tanks, without changing the cell hardware. Designing energy capacity is much easier. Allows scaling and is ideal for long-term energy storage needs.
“In our sulfur-iron flow battery, these electrolytes contain sulfur and iron salts dissolved in water-based solutions. They flow through the battery cell where electrons are exchanged, generating electricity during discharge and storing energy during charging. This technology provides safe, cost-effective, and highly scalable energy storage.”
Initially, when he started experimenting with sulphur-iron, he found a current density of 10-40 mA/sq-cm. However, to be commercially acceptable, they need to reach 80–100 mA/sq-cm. “We have tried various interventions – using metal oxide coatings on the electrodes. We tried various metal oxides; we are still in the process of trying out various materials. To go to commercial scale, we need to reach 80-100 mA/sq-cm,” says Umesh. While they have reached 80 mA/sq-cm, their research and development continues.
Tharam-Thiran Green Energy Flow was registered in 2020 by Vasu along with other members Kaleesh Kumar M, electrochemist and Vaisakh V, product development.
horse racing
For them, scale is the issue. Umesh says, “Our lab scale battery can deliver 100W. To make a 100KW battery, we need to deliver the technology demonstration to different customer segments. Solar power companies producing 100KW will also be interested in trying out a smaller 5KW battery to see if the technology can work. Once it is proven at 5kW, we can scale it up to 100kW as well.” Fortunately, there is strong interest among power producers in testing new technologies, as demand for more efficient batteries will only increase.
After completing their pilot project with their 100W battery, they plan to scale it up to 5kW over the next year and a half. “After pilot testing the 5kW battery, we will build our own 100kW battery.”
Cost
Over the last five years they’ve been working on it, they’ve got it up ₹1.5 crore (~$180,000 USD) to fund extensive research, prototyping and iterative testing. Investments have been primarily directed towards material procurement, laboratory infrastructure, stack construction and validation studies. The growth journey requires not only capital but also technical rigor and strong partnerships, which is critical to transform lab-level innovations into market-ready solutions.
“Currently, our core team consists of four dedicated members who bring expertise in electrochemistry, mechanical engineering and product development. Recognizing the scale of the challenge ahead, we plan to expand our team to more than 20 professionals within the next two years to accelerate technology maturity and commercial deployment.
“We hope to increase 2.5 crore over the next two years to successfully launch our Minimum Viable Product (MVP). This will be used to finalize prototype development, secure intellectual property, complete certification processes, and set up pilot deployment for real-world validation.
“Following the MVP launch, we anticipate the need for an additional Rs 10 crore over a period of next two years to increase commercial deployment. This capital will be used to increase manufacturing scale, expand our team, enhance supply chain capabilities, marketing efforts and establish strategic partnerships with utility and industrial customers.
Competition
Currently, ZH Energy and Lucas Energy are major global players in this specific sector, which gives us and them a significant first-mover advantage. Umesh says, “Our strength lies in our targeted focus on long term storage solutions (10 to 20 hours and above) for installations above 50 kW. While each technology has its own niche, our solution offers a unique combination of low cost, scalable, secure and locally adaptable systems that suit the needs of India’s renewable energy ecosystem.”
future plans
Umesh says, “With the laboratory prototype ready, we are now ready to move into pilot production. Over the next two years, we aim to develop a 5kW system to be released as our minimum viable product (MVP), as well as set up five pilot projects with key stakeholders to validate real-world performance.”
He said, “Our upcoming two-year plan focuses on scaling up to 100kWh battery systems and focusing on commercial deployment. This phased approach allows us to progressively build confidence in the technology, refine manufacturing processes and establish market presence before targeting large-scale industrial and grid applications.”
