Metro trains in Jaipur brake regeneratively dozens of times per hour — but most of that captured energy was being burned off as heat in braking resistors because no adjacent train was accelerating to absorb it. TESAS installed a wayside 1.5 MWh BESS to store and redeploy this energy, reducing traction energy cost by 22%.
Every metro train braking into a station generates 1–3 MWh of recoverable electrical energy per day per station. In standard metro operation, this energy is transferred back to the 750V DC overhead/third-rail supply. If another train isn't accelerating at the same moment, the energy has nowhere to go — and braking resistors dissipate it as heat.
On the Jaipur Metro Green Line (10 stations, 2-minute headways during peak), TESAS's measurement study found that only 42% of regenerative energy was being reused by accelerating trains. The remaining 58% — equivalent to 3,400 kWh per day — was wasted.
At JVVNL's industrial tariff, this represented ₹60 lakh per year of avoidable energy purchase — plus the capital cost of maintaining braking resistors that ran hot 18 hours per day.
TESAS selected Lithium Titanate Oxide (LTO) cells — the only chemistry rated for 400+ daily cycles over 15+ years — for this high-cycle railway application. The 1.5 MWh / 2 MW wayside BESS is DC-coupled directly to the 750V traction bus via a bidirectional DC-DC converter, eliminating the AC inversion losses of grid-scale BESS designs.
4 weeks of sub-second power logging on the 750V DC bus at 4 stations — mapped regenerative pulse amplitude, duration, and frequency.
1.5 MWh LTO pack (rated for 15,000 cycles), 2 MW bidirectional DC-DC converter, custom TESAS control algorithm for DC bus voltage clamping.
Track possession shutdowns used for DC bus connections; fire suppression and SCADA integration completed within 48-hour windows.
Live train testing across all headway scenarios — verified braking capture rate increased from 42% to 86% of regenerative energy.
| Parameter | Specification |
|---|---|
| Cell Chemistry | LTO (Lithium Titanate Oxide) |
| Energy Capacity | 1,500 kWh (1.5 MWh) |
| Peak Power | 2,000 kW (2 MW) |
| DC Bus Voltage | 750V DC traction bus |
| Coupling | DC-DC bidirectional converter |
| Response Time | <50 ms (sub-cycle) |
| Daily Cycles | 400–600 partial cycles |
| Cycle Life Rating | 15,000+ cycles @ 80% DoD |
| Expected Lifespan | 15–20 years (no chemistry replacement) |
| Footprint | 8 × 3 m (fits standard equipment room) |
| Braking Energy Capture Rate | 86% (from 42%) |
| Daily Energy Recovered | 2,950 kWh/day |
| Traction Energy Bill Reduction | 22% |
| Annual Cost Saving | ₹60 Lakh |
| Braking Resistor Heat Reduction | −58% |
| System Availability | 99.2% |
Railway wayside BESS undergoes 400–600 partial charge-discharge cycles per day — vs. 1–2 for commercial BESS. LFP rated at 6,000 cycles would last only ~3 years under this duty. LTO rated at 15,000+ cycles delivers >10 years, giving a dramatically better lifecycle cost even at 30% higher upfront cost.
"TESAS was the only team that understood the DC traction bus architecture from the outset and proposed LTO for the cycle life reason — not just LFP because it's cheaper. That technical confidence was the main reason we selected them. The 22% energy saving has exceeded the feasibility model."
TESAS can conduct a DC bus measurement study on your line and model the wayside BESS savings — typically 18–28% of traction energy cost.