Worked example for a representative outlet. The four-island fuel station below is a model, not a completed Ray2Volt job. Its bills, equipment and savings are assumptions that explain a sizing and payback calculation. The images do not show a customer installation.
Your forecourt, tariff and outage pattern will give a different answer. Request an estimate for your outlet.
Key points
- The model dealer’s fixed per-litre commission makes grid bills and generator fuel important controllable costs; review your actual agreement.
- Check the current IOCL, BPCL or HPCL outlet circular for any solar and automation requirement before designing the plant.
- The illustrative 25 kWp hybrid array and 15 kWh battery produce about 36,250 units a year and show ₹4,83,840 net annual saving in the table.
- PESO and OMC approvals, hazardous-zone placement and a canopy structural review come before installation; model payback is 2.99 years.
A highway fuel outlet near Tirupati or Chittoor may sell around the clock, yet its electrical load changes with traffic. Dispensers, card terminals, lighting and the sales building all need power. A short feeder cut can interrupt a transaction even if the pumps themselves quickly restart. The first step is to separate essential dispensing and payment circuits from loads that can wait.
The outlet in this example pays APSPDCL LT Category II(A) Commercial charges. Its illustrative effective rate is ₹9.80 to ₹10.80 per unit under the APERC FY 2026-27 order dated 25 March 2026; confirm the current order. The same commercial classification may apply to its convenience store, like other retail premises. Demand, duty and feeder reliability matter alongside the unit rate.
The model also has a 25 kVA generator for daytime cuts. At its assumed fuel consumption, diesel power costs ₹26 to ₹30 per unit. A 25 kWp hybrid array with a 15 kWh battery could reduce grid purchases and some short generator runs. This article works through the load, canopy safety, OMC checks and cash flow. See our business solar service and on-grid and hybrid comparison.
Where a fuel outlet spends electricity
Dealer income depends on volume and commission terms, so controllable running expenses deserve attention. This example assigns up to 8% of the dealer margin to generator operation. Treat that percentage as a model assumption; review your own margin statement, electricity bills and fuel logs before using it in a proposal.
The outlet has several different electrical demands to record, especially at a busy forecourt. A short interval meter record, generator hour meter and a list of circuits that must stay live will show whether solar output is used immediately or sent to the grid.
- Dispensing and payments: Four multi-product dispensers and automation servers can stall mid-sale after a voltage dip, with a 3 to 5 minute reboot delay in the example.
- Tank pumps: A 1.5 HP to 2.0 HP submersible turbine pump supports each nozzle; simultaneous sales can create a higher motor starting draw.
- Daytime traffic: The model sees regular vehicles from 7:00 AM to 6:00 PM, giving the array a load to serve directly before any export.
For the selected dispenser and payment circuits, the proposed hybrid inverter and battery aim for transfer in under 10 ms. Commission that performance under a realistic load before relying on it. The battery may avoid starting the 25 kVA generator for a short cut, but its duration depends on the active pumps and state of charge.
The representative four-island outlet
Use the following four-island Chittoor district outlet to follow the calculations. Its traffic, equipment, bill and roof areas are representative assumptions rather than records from an identified dealer.
- Forecourt and services: 4 islands, 4 multi-product dispensers with 16 active petrol and diesel nozzles, a sales building, 2 restrooms, nitrogen inflation and 4.0 kW of canopy LEDs.
- Approved electrical load: 30 kW under APSPDCL LT Category II(A) Commercial.
- Grid use before solar: 3,200 to 3,800 kWh monthly, averaging a ₹36,500 bill at ₹10.15 per unit including fixed charges and duty.
- Generator allowance: One 25 kVA DG set runs 45 to 60 hours monthly in summer and uses about 240 litres, costing ₹23,520 with fuel and lubricant service.
- Roof area: 3,200 sq ft of standing-seam trapezoidal metal canopy plus 1,000 sq ft of flat sales-office roof.
Check the current OMC requirements
Before assuming any OMC requirement, ask the outlet’s oil marketing company for its current circular and approved electrical drawing process. IOCL, BPCL and HPCL may have outlet-level solar, automation and reporting requirements. The example considers those operational goals, but the exact dealership obligation and sign-off route must be confirmed.
Automation and transaction continuity
Dispensing telemetry and payment systems need an approved backup arrangement. If an automation server goes offline, sales data can be delayed and dispensing may be restricted until it reconnects. Test the actual controller behaviour and the OMC’s uptime specification instead of treating solar alone as compliance.
OMC environmental targets
Company targets are separate from your dealership requirements. IndianOil reports a 2046 operational net-zero goal, while HPCL and BPCL report 2040 goals. Solar at retail outlets can contribute, but ask your OMC for the current outlet specification. Your economic case still depends on metered electricity and fuel use.
Design the canopy around hazardous zones
A fuel forecourt is a hazardous area, so canopy solar needs more than a normal commercial roof design. The Petroleum and Explosives Safety Organisation (PESO) requirements, approved site drawing and zone classification should be reviewed before siting any inverter, battery, isolator or cable. The distances below are assumptions for this worked layout, not a substitute for the site’s hazardous-area plan.
- Hazardous-area layout: The model marks 1.5 metres around nozzles and tank vents as Zone 1, and 1.5 to 4.0 metres as Zone 2 under its IS 5572/PESO assumptions. Place the inverter, AC/DC boxes and battery beyond both zones as approved.
- Cable route: Use the specified threaded hot-dip galvanised conduit and barrier glands from canopy to inverter; have the route checked against the classified area drawing.
- Canopy fixing: Aluminium seam clamps grip raised sheet ribs without piercing them. Verify wind load, corrosion protection and the cantilever column capacity.
Keep DC cables and joints away from tank inspection openings and vent outlets. Any damaged insulation or loose connection in a vapour area is a serious fire risk. Ask the installer to show the cable route and the approved isolation points before work starts.
25 kWp output and model cash flow
The example places 43 DCR-compliant 580 Wp N-type TOPCon modules across the canopy for about 25 kWp DC. A 25 kW three-phase Deye hybrid inverter and 15 kWh high-voltage LiFePO4 bank serve the model load. Check canopy capacity, maintenance access, hazardous-zone boundaries and battery location before confirming that layout.
| Operating measure | Before the array | With the model hybrid plant | Change in the model |
|---|---|---|---|
| Grid units bought per year | 42,000 kWh | 11,500 kWh | 72.6% fewer grid units |
| Solar units produced yearly | 0 kWh | 36,250 kWh | Yield of 1,450 kWh/kWp a year |
| Solar used at the outlet | N/A | 84% (~30,500 kWh) | Serves dispensers, tank pumps and lights |
| Surplus credited by the meter | 0 kWh | 16% (~5,750 kWh) | Export assumed on quiet afternoons |
| Typical monthly grid bill | ₹36,500 | ₹11,500 | ₹25,000 less each month |
| Grid bill over a year | ₹4,38,000 | ₹1,38,000 | Grid cost lower by ₹3,00,000 |
| Generator fuel used yearly | ~2,880 Litres/Year | ~800 Litres/Year | 2,080 litres and ₹2,03,840 saved |
| Yearly cleaning and O&M allowance | ₹0 | ₹20,000 | Panels washed and checked monthly |
| Combined yearly cash benefit | Not applicable | Not applicable | ₹4,83,840 for the year |
The capital allowance for this worked hybrid package is ₹14,50,000. It includes the modules, inverter, 15 kWh battery, canopy clamps, protected cable route, metering and electrical sign-offs. Ray2Volt quotes new commercial systems with DCR panels after the June 2026 ALMM List-II shift unless a verified exemption applies. The model allows ₹9 to ₹12 per Wp for the DCR premium, but its total is not a site price.
| Cash-flow measure | Before the model tax effect | After assumed 40% depreciation |
|---|---|---|
| Capital for 25 kWp and storage | ₹14,50,000 | ₹14,50,000 |
| Year 1 tax effect: 40% AD at 25% tax | ₹0 | ₹1,45,000 |
| Capital after model tax effect | ₹14,50,000 | ₹13,05,000 |
| Yearly cash benefit | ₹4,83,840 | ₹4,83,840 |
| Calculated simple payback | 2.99 Years | 2.69 Years |
| Model internal rate of return | 31.4% | 36.8% |
| Model net saving over 25 years | ₹1.05 Crores | ₹1.07 Crores |
When the battery can reduce DG use
A generator still has a role during a long outage or when the battery cannot carry the required pumps. The hybrid design can reduce starts and light-load running, subject to controls and the actual power drawn by dispensers, lighting and the sales building. Use the generator service records when estimating the maintenance benefit.
- Light-load generator running: At 15% to 20% load, the model 25 kVA set can wet-stack, fouling exhaust and injectors; review its actual loading.
- Generator service: About 50 hours a month may call for oil and filter changes every four months, adding ₹18,000+ a year in this example.
- Battery operation: The inverter and LiFePO4 bank avoid engine oil and routine generator noise. The model assumes more than 6,000 cycles and a 10+ year design life; the quoted lithium-ion product warranty is 10 years and electrical checks still matter.
Under its assumptions, the table calculates ₹4,83,840 net annual saving and 2.99 years simple payback, or 2.69 years after the model tax effect. Those are worked-example figures, not a return promised to a dealer. Businesses typically assess 3 to 5 years after a site audit; outage hours, exports and capital cost can all change this result.
Frequently asked questions
What must be checked before putting panels on a fuel canopy?
Canopy panels may be acceptable when the outlet’s approved hazardous-area and structural designs allow them. Keep inverters, batteries and electrical isolation outside the classified zones on the approved drawing, and use the specified conduit and separation from vents. Obtain the necessary OMC and PESO review before installation.
Do all oil marketing companies require outlet solar?
An OMC may seek lower outlet energy use, improved automation uptime and progress against its environmental targets. Requirements differ by company and dealership agreement. Ask IOCL, BPCL or HPCL for the current circular that applies to your site rather than assuming a universal solar mandate.
How can a hybrid inverter reduce generator starts?
The hybrid inverter can supply selected circuits from solar and the 15 kWh battery during a grid cut, with a model transfer under 10 ms. That can avoid starting the 25 kVA generator for brief interruptions. Check pump starting currents, battery state and the tested transfer time; retain generator backup for longer cuts.
Can a fuel dealer use accelerated depreciation?
An eligible business may use 40% written-down-value depreciation under section 33 of the Income-tax Act, 2025. Sole proprietorships, partnerships and companies need their own tax review, including the date the asset enters use. Ask your chartered accountant to confirm the current rate and eligibility; Ray2Volt does not give tax or investment advice.
What payback does the 25 kWp example calculate?
The 25 kWp model gives 2.99 years simple payback and 2.69 years after its assumed tax effect, using ₹9.80 to ₹10.80 per unit and the stated diesel savings. Tariffs and schemes change, so confirm your own eligibility and live tariff. A site-audited business estimate should normally be presented as a typical 3 to 5 year range, never a guarantee.
Ray2Volt Solar Private Limited
We design, install, and service rooftop solar for homes and businesses across Tirupati district and Andhra Pradesh, from PM Surya Ghar residential systems to commercial and industrial plants. Every enquiry starts with a free power audit.
Check solar options for your fuel outlet
Send a recent power bill, canopy drawing and generator run log. We will review demand, roof strength and safety clearances before proposing a site-specific hybrid system.
