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Hybrid Off-Grid System Load Balancer

Combine your solar, wind, and hydro generation estimates against your daily load to see total coverage and whether you're looking at a surplus or a shortfall — bring the numbers from the individual calculators above, this adds them up.

Total daily generation12.0 kWh
Coverage of your load80%
Daily shortfall3.0 kWh

How to measure your inputs

  • Solar/wind/hydro daily kWh: from the Solar Array Size, Wind Turbine Output, and Micro-Hydro Power calculators respectively (see the methodology note for exact conversions).

Methodology

Pure addition and comparison: total generation = solar + wind + hydro (kWh/day); coverage % = total ÷ daily load × 100. Deliberately doesn't recompute each source's own physics-based output — that already happens correctly in each dedicated calculator.

Why combining sources changes the reliability picture, not just the total

This tool adds; it doesn’t recompute

Solar, wind, and hydro output are each governed by real, different physics — already handled properly by their own dedicated calculators (Solar Array Size, Wind Turbine Output, Micro-Hydro Power). This tool deliberately doesn’t duplicate that math; it takes the daily kWh each source contributes and adds them against your load, so the underlying physics stays correct in one place rather than being recalculated (and potentially drifting out of sync) here.

Why a hybrid system is often more reliable than any single source alone

Solar and wind often complement each other on different days (calm sunny days vs. windy overcast ones), and hydro — where available — tends to run continuously regardless of weather. A system hitting 100% average coverage from solar alone can still have real shortfall days; combining sources with different weather dependencies genuinely improves day-to-day reliability, not just the annual average.

What "100% coverage" doesn’t tell you

This calculator compares average daily generation against average daily load — it doesn’t model hour-by-hour matching (whether generation happens when you actually need it) or multi-day weather runs. Even a system averaging well above 100% coverage still needs battery storage (see the Battery Bank Size calculator) to bridge the gap between when power is generated and when it’s used.

Frequently asked questions

How do I get the daily kWh figures this calculator needs?

Use Swales’ Solar Array Size calculator for your solar contribution, the Wind Turbine Output calculator (divide its annual kWh by 365 for a daily figure) for wind, and the Micro-Hydro Power calculator (multiply kW by 24 hours if your flow is roughly constant) for hydro.

Why combine solar and wind instead of just oversizing one?

Solar and wind resources often anti-correlate somewhat — calm days are frequently sunnier, and windy days are frequently overcast — so a modest combination of both tends to produce steadier day-to-day output than a single, larger installation of just one source sized to the same average total.

What does a coverage percentage above 100% actually mean?

It means average daily generation exceeds average daily load — useful headroom for cloudy/calm stretches, but it doesn’t guarantee every single day is covered, since generation and consumption timing still need to be reconciled with battery storage.

Do I still need batteries if my system shows a surplus?

Yes — this calculator compares averages, not real-time matching. Batteries bridge the gap between when your system generates power (e.g. midday sun) and when you actually use it (e.g. evening), regardless of whether your long-run average shows a surplus.