Pillar 1 of 5 · kills: Grid power after sunset
Near-zero grid dependency. 22 hours a day, 95–100% solar.
Six hours of concentrated sunlight, stored as heat in fluid and sand, run a PEM electrolyser for twenty-two.
Modelled saving
₹60–80/kg
40–60% grid electricity → 0–5%
2 · The mechanism
Curved-panel concentrators capture 15–20% more energy than flat panels at the same footprint, sized for Punjab's 5.5 and Odisha's 5.2 kWh/m²/day. Direct power drives the electrolyser through the day; the surplus does not go to a battery.
It goes into two thermal stores. Under-panel fluid storage (an Exowatt-type approach) absorbs excess heat during peak generation and releases it for four to six hours after sunset. A sand battery — industrial by-product sand heated to 500–600 °C — holds a deeper reserve for the morning ramp and any shortfall, with a 25-year life and no degradation cliff.
The electrolyser is the fourth layer. A PEM unit in the H-TEC ME450 class runs at ~74% efficiency (HHV), starts in about ten minutes rather than an hour, and follows a varying solar input without penalty. It is modular: capacity grows from 1 MW to 3 MW per site by adding stacks, and future improvements arrive as bite-sized upgrades rather than plant replacement.
3 · The components
Everything on this page is bought, not invented.
| What is used | Who makes it | Maturity |
|---|---|---|
| PEM electrolyser, 1 MW, 450 kg/day | H-TEC SYSTEMS class (in discussion) | Commercial, 25-yr track record |
| Curved-panel solar concentrators | Indian EPC supply (in discussion) | Commercial |
| Under-panel fluid thermal store | Exowatt-type approach | Pilot-proven, US |
| Sand battery, 200 kWh | Polar Night Energy-type (in discussion) | Commercial, Finland |
| Plant control and power electronics | Standard industrial supply | Commercial |
Supplier names given by class. Partners are in discussion unless a written agreement exists; none is implied as an endorsement.
4 · The numbers
₹60–80/kg from grid elimination, plus ₹25–30/kg from PEM efficiency
Basis. Modelled against a 40–60% grid-dependent plant buying industrial power at Punjab and Odisha tariffs.
Sensitivity. A 10% shortfall in irradiance costs roughly 1.5 hours of autonomy before the two-hour margin is touched; the saving holds above ₹55/kg.
- 22hours/daymodelled
- 95–100% solar
- 0–5%modelled
- vs 40–60% industry
- ~74%HHVsupplier spec
- vs alkaline 60–65%
- 19%capacity utilisationmodelled
- vs 16–17% industry
- 4–6hours post-sunsetmodelled
- hours post-sunset
- 6–8hours backupmodelled
- hours backup
5 · What we still need to prove
- 01Integrated thermal handover — direct solar to fluid to sand — has not yet been run as one control loop on one site.
- 02Sand-battery-to-electricity round trip at our scale needs a measured, not modelled, efficiency figure.