Net present value↗
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Lifetime modeled benefit—
Preparing solar model
✳ THE SOLAR INVESTMENT COMPASS
Make every
sunlit hour
count.
See the energy, the economics and the trade-offs behind your solar decision. Ground your forecast in PVGIS data — then make it your own.
YOUR INVESTMENT / AT A GLANCE
The decision dashboard.
Illustrative model · awaiting live data
Simple payback⌛
—
Estimated break-even—
Annual production☀
—
—kWh/kWp
Year-one benefit◴
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Before annual operating costs—
01 / SOLAR PROFILE
A year of sunlight
Monthly solar generation and where that energy goes.
Used on siteExportedDemand
02 / ENERGY STORY
Your energy balance
First-year projection
SELF-SUFFICIENCY—
Solar used on site—
Sent to grid—
Bought from grid—
03 / FINANCIAL PATH
When does it pay back?
Nominal cumulative cash flow, plus a ±10% solar-output range.
Discounted payback—
Project IRR—
Solar LCOE—
04 / DECISION LENS
✳Reading the results
MODELED OUTLOOK
Review your energy economics.
Results depend on your actual quote, billing structure, and solar usage pattern.
✳Solar resource estimates are illustrative until a successful PVGIS response. Tariffs and project costs are user inputs, not verified market quotes.
02 / YOUR SYSTEM
Design for your real life.
Every assumption is editable. Change the site or roof and update PVGIS; change a price and your economics update immediately.
03 / THE SCENARIO LAB
Better questions. Better decisions.
Explore the changes that actually move the numbers. Then compare a saved set of alternatives side by side.
INSTANT LEVERS
Financial changes reuse the current solar yield; no extra PVGIS call.What changes the outcome?
SIZE OPTIMIZER
Find the best-fitting system size.
Compare sizes under your current tariffs, cost per kWp and estimated self-use. These are scenario calculations, not installer quotes.
No optimization run yet
Run the optimizer to compare 3–12 kWp alternatives.
MY SCENARIO VAULT
Save it. Compare it.
ⓘSaved scenarios stay in this browser unless you export them. Import/export does not upload your financial data.
WHAT-IF ANALYSIS
How resilient is the return?
NPV under ±10% solar output and changes in annual tariff growth.
04 / DAILY ENERGY
Follow the flow of a day.
Explore how solar, household demand and battery charging interact. This is a representative-day simulator, not measured hourly PVGIS output.
REPRESENTATIVE-DAY MODEL
Choose the season and household rhythm.
24 HOURS / POWER
Sunrise to sunset
Representative average-day kilowatts by hour.
Solar outputHousehold demand
DAILY ENERGY BALANCE
Energy in motion
The hourly shape is synthesized from monthly totals and assumed demand timing. It is not observed weather or meter data; do not use it as an engineering battery dispatch guarantee.
PRACTICAL ACTIONS
Timing can be worth more than size.
05 / CASH-FLOW LEDGER
No black-box economics.
Inspect the annual energy, avoided grid purchases, operating expenses and cash flow behind every projection.
PROJECT VS EQUITY RETURNS
Add an optional financing lens.
Project NPV remains unlevered. Debt service affects separate equity cash-flow results.
Project NPV—
Equity NPV—
Annual debt service—
Equity payback—
YEAR-BY-YEAR / DETAILS
Your cash-flow audit trail
| Year | PV (kWh) | Self-use | Export | Grid savings | Export revenue | Expenses | Project cash | Equity cash | Cum. cash |
|---|
06 / DATA & TRUST
Know where every number comes from.
Climate outputs, financial assumptions, model limitations and what to verify before you buy — all clearly separated.
01
European Commission PVGIS 5.3
Location-specific historical climate-based solar production. The app queries PVcalc through a same-origin Cloudflare edge Worker.
Open official source ↗02
Open-Meteo Geocoding
Place-name search to obtain coordinates. It is not a measured roof assessment and cannot determine building obstructions.
Open official source ↗03
Your project assumptions
Electricity tariffs, grants, system costs, module depreciation and demand timing come from your inputs. No live tariff feed is claimed.
CURRENT CALCULATION
Data provenance & confidence
MODEL NOTES
Transparent, not omniscient.
01
Solar production
PVGIS returns 12 monthly climatological outputs. Estimated production is shown explicitly when the API is unavailable. PVGIS is not a forecast of next year's weather.
02
Financial calculation
Annual avoided purchases and exports minus maintenance and replacements yield annual cash flows. NPV discounts those cash flows at your chosen rate.
03
Self-use & storage
Self-use and battery operations are monthly approximations, not hourly co-simulation. Real battery sizing needs measured interval consumption and dispatch rules.
04
Before committing
Get a site survey, electrical design, actual installer quote, meter profile, current supplier tariffs, export arrangements and applicable incentive eligibility.
✳
For planning and comparison only; no investment, tax or engineering guarantee. This tool never asserts an incentive or tariff without your confirmation.