Financial and Energy Consumption Analysis
Energy consumption was determined based on the number of days (50 days) in which the Click & Grow machines were in use. Since the machines only utilized light for 16 h a day, the total hours in which energy was consumed was 800 h. In accordance to the manufacturer’s information on power consumption, each device consumes 6.2 kWh. Furthermore, Singapore’s electricity price is currently set at S$0.2255 kW-1 h-1 \cite{2021a}. Calculations for total energy consumption for one machine, one spinach, and total for the experiment were based on the information above. Water consumption was calculated based on the total utilization of water at the time of harvest. A total of 5 L of water was added to each machine for the 50-day growing season. As of 2021, Singapore’s National Water Agency charges S$1.52 per m3 of water. Additionally, the total carbon footprint for red spinach growing cycle was calculated based on Singapore’s Operating Margin (OM) GEF, which is 0.4085 kg CO2 kW-1 h-1 \cite{transformation}. The exact pricing of the above-mentioned resources may vary year-to-year and depend on the usage in other jurisdictions. All referenced values are summarized in Table 4.