A 20 MW solar IPP in Barmer, Rajasthan was losing 12–18% of annual generation to grid curtailment — grid operator curtailment instructions during low-demand periods cost the developer ₹1.8 Cr per year in foregone revenue. TESAS co-located a 10 MWh / 5 MW BESS to store curtailed energy and deliver it on command.
The 20 MW solar plant (40,000 bifacial panels, commissioned 2023) was contracted under a 25-year PPA with RUVNL at ₹2.68/kWh. Annual expected generation was 40 MUs at 23% CUF — delivering ₹10.7 Cr annual revenue.
However, the Rajasthan SLDC began issuing curtailment instructions in 2024 as the state reached RE oversaturation during low-load winter afternoons. On peak curtailment days, the plant was generating zero from 12 PM to 4 PM — wasting peak irradiance hours. Annual curtailment averaged 15%, costing ₹1.8 Cr/year in foregone revenue — with the trend worsening.
The PPA didn't compensate for curtailed energy. The developer needed a solution to convert a "must curtail" plant into a "dispatchable" one — allowing export during evening peak when SLDC actively needed power.
TESAS designed a 10 MWh / 5 MW BESS system using containerised LFP cells, co-located at the solar substation. The TESAS AI dispatch controller receives SLDC day-ahead schedules and automatically decides when to store curtailed solar vs. discharge to meet the evening dispatch commitment.
3 years of SLDC curtailment data + irradiance data used to size BESS at 10 MWh / 5 MW — optimal for storing afternoon curtailment and dispatching 3–4 hours into evening peak.
5 × 2 MWh containers with IP65 enclosure, positive pressure N₂ purge, liquid cooling set to 28°C despite 48°C ambient, and sand filter on all air intakes.
ML model trained on GHI forecasts, SLDC historical curtailment, DSM penalty structure, and LFP degradation curves — optimises charge/discharge to maximise revenue while protecting battery life.
IEC 60870-5-104 protocol integration with SLDC SCADA — BESS receives updated dispatch instructions in real time and adjusts output within 1 dispatch block (15 minutes).
| Parameter | Specification |
|---|---|
| Battery Chemistry | LFP, prismatic cells (CATL) |
| Gross Energy Capacity | 10,000 kWh (10 MWh) |
| Usable Energy | 9,200 kWh (92% DoD) |
| Power Rating (PCS) | 5,000 kW (5 MW) |
| Grid Voltage | 33 kV (AC coupled via transformer) |
| Thermal Management | Liquid cooling, maintains 25±3°C |
| Enclosure | 5 × 20ft ISO containers, IP65, desert-grade |
| Ambient Rating | −5°C to +55°C |
| Communications | IEC 60870-5-104, IEC 61850, Modbus |
| Fire Suppression | Novec 1230, auto-trigger per container |
| Cycle Life | 6,000 cycles @ 92% DoD |
| Warranty | 10 years, 80% capacity retention |
| Curtailment Instances | 0 (from 34 in prior year) |
| Energy Dispatched via BESS | 8.2 MWh/day average |
| SLDC Schedule Accuracy | 98.1% (within 15% band) |
| DSM Penalties | ₹0 (from ₹12L prior year) |
| Additional Revenue | ₹1.8 Crore / year |
| System Availability | 99.4% |
TESAS applies the same BESS architecture to wind farms — where BESS smooths the intermittent output and fills the 18–24 hour wind generation "holes" with stored energy. We have deployed 3 wind-BESS hybrid projects in Gujarat and Tamil Nadu using NMC + LFP chemistry combinations.
"With BESS we stopped being a curtailment liability for the grid and became a dispatchable asset. SLDC now asks us when we can deliver — we don't wait for permission to export. The project financials improved dramatically and we're looking at two more BESS co-location projects with TESAS."
TESAS will analyse your SLDC curtailment history and model the optimal BESS co-location size and dispatch strategy — free of charge.