Tech OVN

Calculator

Solar Self-Consumption Calculator

See how much of your rooftop solar generation actually offsets grid power versus how much gets exported at a discount. Self-consumption % is the silent multiplier on solar ROI — and most owners overestimate theirs by 15-25%. Pick your region, plug in your plant + load, and see annual savings, export earnings, payback, and carbon offset.

Inputs

Result

Self-consumption %
100%
Annual generation
124.8 MWh
Self-consumed
124.8 MWh
Exported to grid
0 kWh
Total annual benefit
₹11.2 L
Savings ₹11.2 L + export earnings ₹0
Simple payback
4.0yrs
Blended kWh value
₹9.00/kWh
Carbon offset: 89.9 tCO₂/yr (using 0.72 kgCO₂/kWh grid factor for INDIA)

How this works

The calculator models a simplified annual energy balance:

Annual generation = Plant size (kWp) × Specific yield × Performance ratio
Daytime load = Annual load × Daytime load share
Self-consumed = MIN(Generation, Daytime load)
Exported = Generation − Self-consumed

Annual savings = Self-consumed × Grid tariff
Annual export earnings = Exported × Feed-in tariff
Total annual benefit = Savings + Export earnings
Simple payback = Plant cost / Total annual benefit

This is an annual approximation. Real self-consumption depends on hourly matching of generation against load — for accurate measurement, you need behind-the-meter hardware on three measurement points (generation, consumption, grid). That's what Tech OVN's solar monitoring system does.

Typical self-consumption ratios by facility type

Indicative ranges — actual ratios vary by plant sizing, load profile, and weather. The lower number assumes plant is over-sized for daytime load; the higher number assumes good sizing match.

Facility typeTypical self-consumptionWhy
Hotel / hospitality70–90%24/7 load profile absorbs almost all daytime generation
Hospital75–95%Continuous critical load + HVAC during the day
Manufacturing (single shift)60–80%Daytime production aligns with solar generation hours
Manufacturing (multi-shift)75–90%Larger continuous load absorbs daytime generation
Commercial office50–75%Weekday-only daytime load; weekend export losses
Data centre60–80%Continuous load but typically over-sized solar plant
Warehouse / logistics30–55%Limited daytime electrical load relative to roof area
Cold storage70–85%Continuous compressor load matches generation

From estimate to measurement

This calculator gives you a back-of-envelope view. The next step — when you're sizing a plant, validating EPC claims, or reporting ESG carbon offsets — is hardware measurement on the three points that matter: solar generation, site consumption, and grid import/export. Tech OVN's solar monitoring system does exactly that, with Class 0.5S meters and a multi-site cloud dashboard.

Solar PV Monitoring System (Behind-the-Meter) →Industrial Energy Monitoring System →Energy Audit ROI Calculator →

Frequently Asked Questions

Common questions about solar self-consumption, performance ratio, and how to actually increase your self-consumption %.

Solar self-consumption % is the share of solar generation consumed on-site rather than exported to the grid. For commercial and industrial owners with daytime loads, high self-consumption usually means better ROI — because self-consumed solar offsets grid energy at the full retail tariff, while exported solar typically receives a much lower feed-in / wheeling tariff. Tracking actual self-consumption (not estimated) is one of the highest-value metrics for solar plant ROI.
Most rooftop solar buyers focus on plant size and generation. The bigger lever is what fraction of that generation displaces grid power versus what gets exported at a discount. Example: in India a self-consumed kWh saves ₹9 (grid tariff) while an exported kWh earns ₹3-4 (feed-in tariff). A plant that self-consumes 80% of its generation produces ~50% more revenue than the same plant exporting 80%. Self-consumption is the silent multiplier on solar ROI.
It compares annual generation (plant size × specific yield × performance ratio) against the daytime portion of facility load (annual load × daytime load share). Self-consumed = the smaller of the two; the rest is exported. This is a simplified model — real self-consumption depends on hour-by-hour matching of generation with load. For accurate measurement, the only path is hardware-grade behind-the-meter monitoring (which is what Tech OVN's solar monitoring system does).
Specific yield is annual energy generated per kWp installed (kWh/kWp/year). It varies by location: India 1500-1700, UAE / Middle East 1800-2000, Africa 1700-1900, Europe 900-1300, USA 1300-1700, Southeast Asia 1400-1600. Your EPC contractor's commissioning report or the inverter's first-year data is the source of truth. We default to regional averages when you pick a region.
PR is actual energy delivered as a % of theoretical maximum. Losses include inverter conversion (~3-5%), DC cabling (~2-3%), AC cabling (~1-2%), soiling (~3-7% depending on cleaning frequency), shading, and module degradation. Typical PR for a well-designed plant is 75-82%. Below 70% suggests something is wrong (heavy soiling, undersized inverter, partial shading, faulty strings) — exactly what continuous monitoring catches.
When solar generation exceeds daytime load, the surplus is exported to the grid at the feed-in tariff — typically 30-60% of the retail tariff. Every exported kWh represents lost value compared to a self-consumed kWh. The calculator shows this gap so you can size load-shifting opportunities (running discretionary loads during solar hours, battery storage, EV charging during the day) that would convert export kWh into self-consumed kWh.
Three levers: (1) shift discretionary loads (HVAC pre-cooling, water heating, EV charging, pumping, batch processing) into solar generation hours; (2) right-size the plant — over-sizing increases export ratio; (3) add behind-the-meter battery storage to absorb excess generation for evening use. The first lever is free and usually delivers 5-15% additional self-consumption with no capex. None of this works without continuous measurement of grid vs solar — guess-work doesn't move the needle.
It works for any plant size, but the buyer profile we serve is commercial and industrial rooftop solar — typically 50 kWp to 5 MWp. Residential solar follows the same math but with much smaller numbers. Utility-scale solar plants are designed primarily for export, so the self-consumption framing doesn't apply.