Energy use and carbon footprint of the tomato production in heated multi-tunnel greenhouses in Almeria within an exporting agri-food system context

Highlights: • LCA is strategic to environmental assessment of technological changes in agriculture. • Cultivating heated tomatoes demands 5.4 times more energy per hectare. • Cultivating heated tomatoes increases 2.75 times the CO₂-eq emissions per kilogram. • Energy for heating amounts to 56.8% of the on-farm cumulative energy demand. • The supply chain increases 2–3 times the CO₂-eq emissions of heated and unheated crops. Almeria (Spain) is one of the most important agricultural centers of vegetable cultivation in Europe. The search for technological innovation has led to the introduction of climate control systems in greenhouses in Almeria to improve productivity during the cold season. Up to now, no studies have analyzed the energy behavior of introducing this technology in this specific region. The objective of the present study is therefore to analyze the energy use and carbon footprint (CF) of the tomato production in heated multi-tunnel greenhouses in Almeria from a life cycle perspective (cradle to regional distribution center approach). The results obtained show that the introduction of heating systems in multi-tunnel greenhouses in Almeria allowed for an increase in the annual productivity per hectare and kilogram below the increment in cumulative energy demand (CED). The on-farm CED and CF were estimated at, respectively, 13.4 MJ and 0.92 kg CO₂-eq kg⁻¹ of gross production. The impacts were thus 3.3 and 2.75 times higher than those of the unheated crop. The use of energy and infrastructure (86.1%), fertilizers, and infrastructure (66.9%) were the main hotspots of the heated and unheated tomato crops. With regard to the marketed output and the supply chain, the CF and CED of heated tomatoes were 2.07 kg CO₂-eq and 29.30 MJ kg⁻¹, with a non-renewable EROI (energy return on investment) (0.030:1) that was 48% lower than the one obtained with unheated tomatoes. On-farm production (64.1%), transport, and packing (65.9%) were, respectively, the main hotspots in the heated and unheated tomato agri-food systems. The production of heated tomatoes in Almeria may continue to be a better energy option than locally producing the crop in heated greenhouses in northern Europe, as long as other options related to the seasonal local production and changing diets are not taken into account.