Hitachi Energy Rooftop Solar: ₹18 Lakh Saved a Year, Zero Capex
Published Nov 5, 2026
Hitachi Energy's 600 kWp rooftop solar plant in Doddaballapura, Bengaluru delivered 8 lakh units and ₹18.2 lakh in savings in 12 months, with zero capex.
SustVest owns and runs a 600 kWp rooftop solar plant at Hitachi Energy India's factory in Doddaballapura, Bengaluru Rural, Karnataka. Hitachi Energy spent no capital. From October 2025 to September 2026 the plant delivered 8.00 lakh units of solar power and saved Hitachi Energy ₹18.2 lakh, based on actual billed units.
At a glance
Client | Hitachi Energy India Limited |
Industry | Energy technology (power grid equipment) |
Location | Doddaballapura, Bengaluru Rural, Karnataka |
Capacity | 600 kWp DC / 440 kW AC rooftop solar |
Model | OPEX (RESCO), zero capex |
Commissioned | August 2024; owned and operated by SustVest since 17 October 2024 |
Generation (last 12 months) | 8,00,371 kWh, or 1,334 kWh per kWp |
Savings (last 12 months) | ₹18.2 lakh, net of solar payments |
CO₂ avoided (last 12 months) | 5,69,624 kg, equal to about 26,166 trees |
The problem: grid power costs and climate targets
Hitachi Energy's Doddaballapura factory buys power from BESCOM on a high tension (HT) industrial tariff, paying about ₹7.43 per unit.
As a global energy technology company with its own climate targets, it also wanted on-site renewable power without tying up capital in an asset outside its core business.
Why the plant needed a new owner
The rooftop plant was first contracted with another developer in 2023 and built in 2024, but it still needed a long-term owner to fund and run it. Instead of restarting the process, Hitachi Energy signed a three-way novation (a transfer of the contract) on 17 October 2024 that moved the power purchase agreement to SustVest. SustVest funded the plant and took over operations and monthly billing, and Hitachi Energy kept a zero-capex solar supply below its grid rate.
What SustVest runs
Capacity: 600 kWp DC / 440 kW AC rooftop solar plant across two roof orientations
Timeline: commissioned in August 2024; contract moved to SustVest on 17 October 2024; SustVest billing from late 2024
Hardware: 1,101 EVVO 545 Wp solar modules and four EVVO 110 kW string inverters
Beyond O&M: SustVest also carried out roof waterproofing on the building in December 2025, alongside routine operations and maintenance
Learn more about zero investment OPEX solar and SustVest's solar plant monitoring.
Results
Savings: ₹18.2 lakh net in the last 12 months (October 2025 to September 2026); about ₹36 lakh net since late 2024
Generation: 8,00,371 kWh in the last 12 months, 1,334 kWh per kWp (3.7 units per kWp per day); 15,90,115 kWh billed since late 2024
CO₂ avoided: 5,69,624 kg in the last 12 months; 11,31,685 kg since late 2024 (at the CEA grid factor of 0.7117 kg per kWh)
Peak months: 83,993 kWh in March 2025 and 81,960 kWh in March 2026
Monthly solar generation, last 12 months
Month | Units (kWh) |
October 2025 | 62,810 |
November 2025 | 56,776 |
December 2025 | 62,357 |
January 2026 | 59,022 |
February 2026 | 64,320 |
March 2026 | 81,960 |
April 2026 | 81,213 |
May 2026 | 76,139 |
June 2026 | 71,242 |
July 2026 | 57,557 |
August 2026 | 58,720 |
September 2026 | 68,256 |
Total | 8,00,371 |
What we learned: the monsoon dip is real
The plant ran at 94% of its PVsyst P90 estimate over the last 12 months (8.00 lakh units against 8.49 lakh). The monsoon cuts output hard: July and August 2026 produced 57,557 and 58,720 kWh, about 28% to 30% below March 2026's 81,960 kWh.
Frequently asked questions
1. How much does a 600 kWp rooftop solar plant save a manufacturer in Karnataka?
About ₹18.2 lakh a year at Hitachi Energy's Doddaballapura plant, based on actual billed units. The 600 kWp plant delivered 8.00 lakh units from October 2025 to September 2026, supplied under SustVest's OPEX model at a fixed tariff below the roughly ₹7.43 per unit grid rate. Hitachi Energy spent no capital.
2. Can a solar developer take over an existing rooftop plant and its PPA?
Yes, through a novation agreement signed by the factory, the original developer and the new owner. At Hitachi Energy's Doddaballapura site, a three-way novation on 17 October 2024 moved the power purchase agreement to SustVest, which funded the plant and took over operations and billing, with no capital from Hitachi Energy.
3. How much does rooftop solar generate per kW in Bengaluru?
About 1,330 units per kWp a year, or 3.7 units per kWp a day, based on Hitachi Energy's 600 kWp plant at Doddaballapura from October 2025 to September 2026. Output peaks in March and April and drops by about 30% in July and August during the monsoon.
4. What is zero investment (OPEX) rooftop solar?
Under SustVest's OPEX (RESCO) model, SustVest funds, builds, owns and maintains the rooftop solar plant. The factory pays only for the solar units it uses, at a fixed per-unit tariff below its grid rate. Savings start from the first month, with no capital spent by the factory.
See what your factory roof could save
SustVest builds, owns and runs rooftop solar plants for factories across 13 Indian states, with zero upfront investment.