Fig. 3: Annual energy use intensity per unit yield and per unit of growing area, by yield density.

Results by crop type are shown in (a, b), by facility type in (c, d), by presence or absence of energy efficiency measures in (e, f), and by modeled versus measured analysis in (g, h). Each symbol indicates a cultivation trial in the meta-analysis for which the corresponding metric can be calculated. Yields reflect total annual amounts harvested per growing surface (kg/m²-y) which in most cases occur multiple times each year and often on more than one growing level or surface, particularly in plant factories. Cases lacking yield density are not plotted. Corresponding values for open-field crops provided in some of the CEA studies are shown in (c, d). The tendency towards lower yields and lower energy intensities for open-field cultivation is evident. Sample sizes are indicated in the legends. Crops included in some of the aggregated categories are defined in the caption to Fig. 2 and the data and sources are provided in the Supplementary Information.