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Solar vs Diesel Generator Calculator

Side-by-side 10-year cost comparison — solar with PM Surya Ghar subsidy vs diesel generator with fuel, maintenance, and replacement.

Backup power requirements

5 kWh20 kWh200 kWh
5 years10 years25 years

10-year total cost comparison

Solar Total
₹3,62,000
Net cost + maintenance
Diesel Total
₹34,72,969
Genset + fuel + replacement
Solar Savings
₹31,10,969
Break-even in Year 1
DG CO₂ Avoided
68.5 t
25,550 L diesel not burned

Year-by-year cumulative cost

What the numbers show

Over 10 years, solar saves ₹31,10,969 vs running a diesel generator for the same load. Solar also avoids 68.5 tonnes of CO₂ and 25,550 liters of diesel over the same period. Break-even comes in Year 1.

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How to compare solar vs diesel generator costs

Step-by-step guide to comparing 10-year total cost of ownership.

  1. Estimate daily kWh needed

    Sum your loads × daily run hours. Use our Appliance Load calculator if unsure.

  2. Pick analysis period

    10 years is typical for commercial comparison. 15-20 for industrial.

  3. Enter current diesel price

    Check your local pump. UP avg 2026: ₹94-100/L.

  4. Enter solar and genset costs

    From your installer quotes. Include installation and commissioning.

  5. Review break-even year

    When cumulative diesel cost exceeds solar net cost + maintenance.

Diesel generators lose on every metric

Once a workhorse of Indian backup power, the diesel generator now loses on upfront cost, running cost, reliability, and environmental impact. Solar + battery has surpassed diesel in all four dimensions since 2022. Break-even typically arrives in Year 2-3. By Year 10, a solar system has saved 2-4× its own installation cost compared to running a diesel genset for the same load.

Where diesel still makes sense

Very rare use-case backup (under 50 hours/year), short-duration extreme loads that exceed battery output, and sites with no roof for solar. For every other case — daily operation, industrial continuous load, residential backup — solar is cheaper and cleaner.

Quantify the full switch with our CO₂ Savings Calculator, line up the investment recovery in the Payback Calculator, and size the battery side of the replacement with Backup Hours.

Frequently Asked Questions

Is solar cheaper than a diesel generator?

Yes, dramatically. Running a 10 kVA diesel generator 8 hrs/day costs ~₹8-12 lakh over 10 years in fuel alone (at ₹95/L). A 10 kW solar system costs ₹4-5 lakh net of subsidy and runs free for 25 years. Most businesses break even vs diesel in 2-3 years.

What are the running costs of a diesel generator?

Three components: (1) fuel — 0.35 L/kWh at ₹95/L = ₹33/kWh, (2) oil changes, filters, maintenance — ~₹12,000-25,000/year, (3) replacement every 8-10 years. For a 10 kW load running 8 hrs/day, diesel costs ₹8-10 lakh/year.

Is solar reliable enough to replace a generator?

Grid-tied solar + battery hybrid is more reliable than a generator for most businesses. Panels have no moving parts (25-year lifespan), lithium batteries cycle 3,000+ times, and inverters have standby power within 10-20 milliseconds. Generators fail on starter motors, fuel pumps, and old batteries.

What about petrol/LPG generators?

Petrol genset: 20-30% cheaper upfront, but fuel costs 30% more per kWh. LPG: cleaner, slightly cheaper fuel, but limited availability in rural India. Solar still beats all three over 10+ years.

Can I replace my diesel generator entirely with solar?

For daytime loads, yes — grid-tied solar + net metering eliminates daytime generator use. For overnight or all-day critical loads, hybrid solar (with battery) replaces 80-95% of generator running, keeping genset for rare multi-day outages only.

What about commercial / industrial loads?

Commercial solar (no residential subsidy but 40% accelerated depreciation tax benefit) still beats diesel. Payback: 3-5 years. Over 20 years, a factory running 100 kW saves ₹2-4 crore vs diesel generator operation.

How much CO₂ does switching from diesel to solar save?

1 liter of diesel burns to produce 2.68 kg CO₂. A 10 kVA generator running 8 hrs/day burns ~25 L/day = 67 kg CO₂/day = 25 tonnes/year. Solar replaces all of this. Over 10 years, switching saves 250+ tonnes of CO₂.

What about noise pollution?

Diesel generators run 70-90 dB (loud conversation to power drill). Solar + battery: silent. For residential societies, hospitals, and offices near residential areas, this is a major quality-of-life improvement.

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