Engineering reports
Preliminary solar proposal

Solar Quote & Savings Generator

Convert electricity consumption into a transparent preliminary PV proposal. The report separates energy sizing, module rounding, self-consumption, export credit, roof requirement and simple payback so every assumption can be reviewed.

Use actual bill, tariff and site values where possible. Defaults are editable planning assumptions, not universal design values.

Project inputs

Change any assumption and the report updates instantly.

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Solar PV Preliminary Design & Savings Report

Preliminary Solar Proposal

Recommended PV
7.7 kWp
Modules
14 × 550 Wp
Annual generation
10,961 kWh
Simple payback
5.9 years

1. Calculation inputs

Monthly electricity consumption
1,000 kWh/month
Annual electricity consumption
12,000 kWh/year
Target solar offset
90%
Peak Sun Hours
5 h/day
Performance ratio
78%
Selected module power
550 Wp
Self-consumption assumption
70% of PV generation
Retail tariff
₹8/kWh
Export credit
₹3/kWh
Project cost assumption
₹55,000/kW

2. Step-by-step PV sizing

Target annual solar energy
12,000 × 90%
= 10,800 kWh/year
Theoretical DC capacity
10,800 ÷ (365 × 5 × 0.78)
= 7.59 kWp
Required module count
ceil(7.59 × 1000 ÷ 550)
= 14 modules
Actual installed DC capacity
14 × 550 ÷ 1000
= 7.7 kWp
Expected annual generation
7.7 × 5 × 365 × 0.78
= 10,961 kWh/year

3. Energy & financial estimate

PV generation / annual consumption
91.3%
Estimated self-consumed PV energy
7,673 kWh/year
Estimated exported PV energy
3,288 kWh/year
Remaining grid import
4,327 kWh/year
Self-consumption bill saving
₹61,381
Estimated export credit
₹9,865
Estimated annual benefit
₹71,246
Estimated installed project cost
₹4,23,500
Simple payback
5.9 years

Current annual bill reference: ₹96,000. Fixed charges, demand charges, taxes, escalation, O&M, degradation, financing and replacement costs are not included in simple payback.

4. Roof feasibility check

PRELIMINARY PASS

Planning roof requirement = 7.7 kWp × 8 m²/kW = 61.6. Available usable area entered = 100.

Roof factor is an editable planning allowance. Final layout depends on exact module dimensions, orientation, row spacing, setbacks, walkways, obstructions, fire access and structural capacity.

5. Engineering assumptions & warnings

  • • PR is applied as a single aggregate system-performance assumption. Do not separately subtract the same losses again.
  • • Peak Sun Hours should preferably represent site-specific plane-of-array or a justified preliminary solar resource assumption.
  • • Self-consumption is a financial modelling assumption; actual value requires interval load data and a time-series PV profile.
  • • Export credit is user-entered because net metering, net billing and feed-in rules vary by utility and jurisdiction.
  • • Final inverter size, DC/AC ratio, strings, MPPT voltage/current limits, cable sizes, protection and earthing are outside this quick quote and need detailed design.
Preliminary-use disclaimer: This report is an engineering planning aid, not an approved design, guaranteed energy forecast or binding commercial quotation. Verify site conditions, tariff rules, equipment datasheets, structural suitability, applicable standards and utility requirements before procurement or construction.
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What to verify before using this as a customer proposal

12-month bills or interval consumption data
Roof dimensions, setbacks, shade and structure
Exact module and inverter datasheets
Local net-metering / export-credit rules
Electrical SLD, cable and protection design
Taxes, subsidy, O&M and financing scope