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Solar Fish Farm Calculator

Enter aeration HP, pump HP, and climate — get solar kW, 48-hour critical aeration battery backup, and annual diesel savings.

Farm configuration
ponds
gal
Equipment loads
HP
HP
Location & financial
$/kWh
$/gal
Solar system for your fish farm
5.0 kW system — 13 × 400W panels
⚠️ Critical aeration backup: 44.7 kWh battery bank covers 48h of aeration + circulation (746W) — minimum to prevent fish loss during outages.
Continuous pump load746 W
Daily energy (24/7)17.95 kWh/day
Annual energy6,551 kWh/yr
Annual grid cost avoided$851.58/yr
Annual diesel cost avoided$7,861/yr (1,965 gal)
Battery bank (48h, 48V)933 Ah (44.7 kWh)
Inverter size1 kW
Est. system cost$52,560
Payback vs grid61.7 yrs
Payback vs diesel generator6.7 yrs
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How to Use This Calculator

Enter your pond and pump configuration

Start with the number of ponds or tanks and total water volume. Then enter your aeration pump horsepower — this is the most critical load in any fish farm. Enter the total HP across all aerators. A minimum of 0.5 HP per surface acre of pond is standard for catfish or tilapia; intensive recirculating systems may need 2-5 HP per 10,000 gallons.

Add optional loads and location

Automatic feeders and security lighting add small but real energy loads. Select your climate zone to set peak sun hours for your region. Enter your current electricity rate and diesel cost — the calculator shows payback against both grid power and generator operation, giving you a complete comparison.

Understand the battery requirement

The minimum aeration backup for a fish farm is 48 hours for grid-tied systems, 72 hours for off-grid. This is not a conservative estimate — it is the minimum needed to prevent catastrophic stock loss during cloudy weather. Fish farming operations that install solar without adequate battery backup have lost entire harvests during extended outages.

The Formula

Aeration Watts = Aeration HP × 746W/HP Circulation Watts = Circulation HP × 746W/HP Daily kWh = (Aeration + Circulation) × 24h + Feeder × 1h + Lights × 12h, all ÷ 1000 Annual kWh = Daily kWh × 365 System kW = Daily kWh ÷ PSH ÷ 0.80 Panels = System kW × 1000 ÷ 400W (round up) Battery Wh = (Aeration + Circulation) Watts × 48h (72h off-grid) ÷ 0.80 DoD Payback (grid) = System Cost ÷ Annual Grid Cost Payback (diesel) = System Cost ÷ Annual Diesel Cost (0.3 gal/kWh × diesel price)

The diesel generator comparison assumes a standard fuel consumption of 0.3 gallons per kWh — typical for a properly loaded generator. Lightly loaded generators burn more fuel per kWh; a generator running at 50% load may consume 0.4-0.5 gal/kWh. This means solar vs. diesel payback is often 4-7 years in areas with $4+/gallon diesel, far better than the grid payback.

Example

Johnson Catfish Farm — 3 ponds in Mississippi

The Johnson family runs three 2-acre catfish ponds in Mississippi. They have a 1.5 HP aerator system, a 1 HP circulation pump, automatic feeders, and security lighting. They currently run a diesel generator and pay $4.50/gallon. Their climate zone is subtropical (5.2 PSH).

Aeration1.5 HP = 1,119W
Circulation1.0 HP = 746W
Feeders + lights50W + 200W
ClimateSubtropical (5.2 PSH)

Result

Daily energy~47 kWh/day
Annual energy~17,200 kWh/yr
Annual diesel cost~$23,200/yr (5,160 gal)
System size~12 kW / 30 × 400W panels
Battery (48h backup)~2,330 Ah @ 48V (112 kWh)
Est. system cost~$127,000
Payback vs diesel~5.5 years

At $4.50/gallon diesel, the Johnson farm spends over $23,000 per year on generator fuel. A solar system with battery backup pays for itself in 5-6 years and provides 25+ years of near-free operation. The large battery bank (112 kWh) is expensive but non-negotiable — losing a full catfish harvest to a 2-day power outage would cost far more than the batteries.

FAQ

Fish begin dying within hours when dissolved oxygen drops below critical levels. A 24-hour battery only covers one night without solar production. In practice, extended cloud cover or equipment issues can last 2-3 days. The 48-hour minimum for grid-tied systems (72h off-grid) gives you enough time to diagnose the problem, bring in a backup generator, or get grid power restored before losing your stock. Many aquaculture insurance policies require documented backup power systems.
In most cases, yes — especially for farms already running generators. A diesel generator burning 0.3-0.5 gallons per kWh at $4/gallon costs $1.20-2.00 per kWh of electricity generated. Grid power typically costs $0.10-0.15/kWh. Solar (after system payback) costs effectively $0. Fish farms that switch from diesel generators to solar typically see 4-7 year paybacks, then 18+ years of essentially free electricity. USDA REAP grants (up to 25% of system cost) and the 30% federal ITC further improve the economics.
Small pond systems (1-3 HP aeration) typically run $15,000-40,000 installed including battery backup. Medium operations (3-10 HP) run $40,000-120,000. Large commercial farms (10+ HP) run $100,000-500,000 or more. The battery bank is usually the most expensive component due to the large backup requirement — plan on 30-50% of total cost for batteries in off-grid or critical-backup scenarios. Commercial quotes from multiple installers are essential; this calculator provides estimates for planning purposes.
Fish farms are eligible for several programs: (1) USDA REAP Grant — up to 25% of project cost for agricultural producers and rural small businesses (apply before installation). (2) Federal ITC (Investment Tax Credit) — 30% of system cost as a tax credit, applicable to aquaculture operations. (3) MACRS depreciation — 5-year accelerated depreciation on solar equipment (bonus depreciation available). Combined, these can reduce effective system cost by 50-60% for tax-paying businesses, making payback periods of 2-4 years achievable.
Yes — agrivoltaic fish farming (solar panels over ponds) is a growing practice, especially in Asia and increasingly in the US. Benefits include: reduced water evaporation (25-50% less), partial shading that reduces algae growth and maintains cooler water temperatures beneficial for many species, and dual use of the same land. Panel structures are elevated 8-12 feet above pond surface to allow equipment access. Cost is higher than ground-mount due to the specialized structures, but the combined fish and electricity production often doubles the land's revenue per acre.

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