The tank cross-section shows algae cells (green dots) multiplying as light
drives photosynthesis and CO₂ bubbles rise through the culture. Once biomass
density is high enough, cells are drawn through the harvest outlet and converted
into biofuel oil droplets collected below.
μ (growth rate) = μmax · min(I/(I+Ks), CO2/(CO2+Kc), N/(N+Kn))
biomass(t+dt) = biomass(t) + μ·biomass·(1-biomass)·dt − harvest_rate·biomass·0.5·dt
oil_yield% ≈ 20% + 0.3·light% − 0.1·harvest%
- Light intensity — drives the photosynthetic growth term; growth saturates as light approaches its half-saturation constant Ks.
- CO₂ concentration — the carbon feedstock for growth, bubbled continuously through the tank.
- Nutrient level — nitrogen/phosphorus availability; low nutrients cap density even with plenty of light and CO₂.
- Harvest rate — fraction of biomass removed per cycle to produce biofuel; too high starves the standing population.