Powering the Aeration System:
Solar vs Generator vs Land Expansion

PROBLEM The grid cannot power your aeration

The whole financial case in BFS-016 assumes mechanical aeration runs on grid power. That assumption is broken. The local grid connection at the Paombong site cannot carry the load of the floating aerators and venturi pumps. Box B might carry one small pump — but that is not confirmed, and Box A (the 3.4 ha pond holding 68,000 fish) has no usable grid supply at all.

THE MATH Oxygen demand → power needed

We don't guess the equipment — we calculate it. The fish burn oxygen at roughly 250 mg O₂ per kg of body weight per hour. As the stock grows, biomass climbs and so does the oxygen draw. Here is Box A (3.4 ha, 68,000 fish, 34 million litres of water at 1 m depth):

M4 is the design case — the worst night of the cycle. Everything is sized to survive it.

Confirming the equipment spec

The 3 floating aerators + 2 venturi pumps in the plan are correctly sized. Even the lean build covers peak demand; the mid build is the recommended design point:

PATHWAY 1 ☀️ Solar (off-grid)

A solar array charges a battery bank during the day; the battery runs the aerators through the critical pre-dawn window. This is the only pathway with zero recurring energy cost — after the build, the power is free for 10–15 years.

System sizing (critical-window design)

The make-or-break window is roughly 10 PM–6 AM. Sizing the battery to carry an 8-hour run at the design load (not a worst-case 12-hour run) keeps the system affordable while still protecting the fish:

Cost (Philippine pricing, 2026)

Amortized over a conservative 5-year life (10 cycles): the reduced build costs ≈₱85,500/cycle; the full build ≈₱146,544/cycle. Battery is the cost driver — LiFePO₄ is rated 4,000–10,000 cycles (10–15 yr), so 5 years is a deliberately cautious accounting choice.

PATHWAY 2 ⛽ Diesel generator

A single diesel genset runs the aerators directly. Familiar, mobile, and deployable in a week — but it burns fuel every single night for the life of the farm.

Sizing & fuel

A 10–12 kVA single-phase diesel genset (8–9 kW usable) covers the 6.3 kW Box A heavy load with headroom, and can carry Box B too. Diesel gensets burn roughly 0.32 L per kWh at part load:

PATHWAY 3 🌊 Land expansion + tidal exchange

Paombong sits near Manila Bay with twice-daily tidal water exchange through the sluice gates (see BFS-014). The theory: spread the same number of fish over more water at lower density, so the pond's natural oxygen + tidal flushing keeps DO safe without any machines. We researched whether the science supports it.

So tidal exchange can support bangus without aeration — but only at low density. To keep your head-count and harvest tonnage, you'd have to roughly triple your leased footprint to 14+ hectares. The extra rent (₱285K/cycle) is double what a generator burns in fuel and more than 3× the solar amortization — for the same harvest. You'd also need far more pond prep, more dike maintenance, more caretaker labour, and more fingerlings to stock the larger area.

COMPARE Three pathways side by side

DO THIS Recommended action plan

1. Week 1 — Buy the generator. Order a 10–12 kVA silent diesel genset (Greenfield, Kubota, or KHM Megatools — ₱200–220K). This guarantees aeration is live before a single fingerling goes in the water. Have Sean/Aaron confirm 220V single-phase output and a transfer setup at both boxes.
2. Week 1 — Order aerators. Lock the mid build: 3× 750W floating aerators + 2× AVIA ITALIA 2HP venturi pumps for Box A. Stage them before stocking.
3. Before stocking — Wet test. Run the full aeration setup off the generator for a full night and measure DO at 5 AM with a meter. Confirm ≥5 mg/L. This proves the system before fish are at risk.
4. Month 1 — Get 3 solar quotes. While the generator carries cycle 1, get installed quotes from Solaric, local Bulacan installers, and a Lazada-sourced kit for the ~14 kWp / 50 kWh reduced build. Target ₱855K installed.
5. Month 2–3 — Build solar. Install during the cycle while biomass (and aeration demand) is still ramping. Commission it before the Month 3–4 heavy-load window.
6. Month 4 onward — Solar primary, generator backup. Solar runs the nightly aeration; the generator stays fuelled and ready for consecutive overcast habagat nights or maintenance.
7. Cycle 2 — Pure solar economics. From here your nightly power is effectively free and your breakeven sits at ₱75/kg. The generator is now insurance, not a line item.

BOX B The 1.1 ha pond — handle the uncertainty

Box B (1.1 ha, 22,000 fish) reportedly may have grid that can carry one small pump — but it's unconfirmed. Box B's peak biomass is ~5,500 kg, needing only ~1.8 kg O₂/hr at peak — about 1 kW of aeration (one 1,100W floating aerator plus a venturi).

Action: have Aaron run a load test on the Box B grid line during Week 1 — switch on a 1,100W pump and watch for voltage sag or breaker trips. Cheap test, removes the uncertainty.

INTEGRATION How power cost changes BFS-016 breakeven

The BFS-016 baseline assumed free grid power: cycle cost ₱1,744,902, breakeven ₱71.60/kg on ~24,370 kg of harvest. Adding the real power cost shifts breakeven and mid-case profit (at ₱160/kg) as follows: