Table 3 Light parameter, energy demand and photon use efficiency (φC) of the entire process. The energy demand for illumination is derived from QPar, assuming an LED efficiency of 40% and a conversion factor of 4.56 J per photon. φC is calculated from the absorbed photons QPhar and the total C stored in biomass and glycolate at the end of production (Table 1)
Measured values [l−1 reactor run (10 days)−1] | Upscaled values [ha−1 reactor surface y−1] | |
|---|---|---|
Incident light (QPAR) | 22.14 ± 1.5 mol photons | 6.7*107 ± 4.6*106 mol photons |
Absorbed photons (QPhar) | 17.06 ± 1.6 mol photons | 5.2*107 ± 4.9*106 mol photons |
Energy for incident light* | 3.37 ± 0.2 KWh | 10.3 ± 0.7 GWh |
φC (Biomass phase) | 29.84 ± 7.1 [mol photons mol C−1] | |
φC (C fixed in glycolate) | 112.91 ± 10.8 [mol photons mol C−1] | |
φC (overall process) | 74.94 ± 2.8 [mol photons mol C−1] | |