Emission-less greenhouses: dream or reality?

Transcription

1 Workshop sustainable greenhouse 1 Emission-less greenhouses: dream or reality? Cecilia Stanghellini, Wageningen UR Greenhouse Horticulture cecilia.stanghellini@wur.nl EUPHOROS: Efficient Use of inputs in Protected HORticulture Aim of the project: In the European protected cultivation to decrease the use of: Non-renewable energy Water and fertilisers Plant protection products Substrate waste Without damage to productivity Partners: research institutions Partners: business Wageningen UR Greenhouse Horticulture (NL) Estación Experimental de la Fundación Cajamar (ES) IRTA Barcelona (ES) Università di Pisa (IT) University of Warwick (UK) HortiMaX (NL) Ciba poi assorbita da BasF (CH) GroGlass (LV) Perlite (IT) Terra Humana (HU) Cooperativa di produttori Morakert (HU), ora sostituita da Szent István University (HU) Much good about greenhouses but Even un-heated greenhouse production has a Global Warming Potential equivalent to 25 g CO2 per kg tomato N-leaching can be some 2 g NO3 per kg tomato Euphoros consortium, 21 Tomato production is presently hardly profitable across the EU Growers will invest in decreasing emissions only insofar as this improves their balance sheet Examples decreasing resource use = smart design cover materials ventilation capacity decreasing waste = process management ventilation thermal storage irrigation management evaluation of means for decreasing environmental impact of passive greenhouses

2 Workshop sustainable greenhouse 2 Smart greenhouse covers light-saturated heat inside Morphogenesy s Color & Insects photosynthesis + heat in the dark Effect of haze (degree of diffusion) Yield of cucumber upper leaves high haze Net photosynthesis standard cover Incident light Dueck et al., 29 Net photosynthesis Cumulative production (kg/m 2 ) Yield of cucumber Incident light upper leaves standard cover The benefit of a diffusing cover is likely top be even more at lower latitudes than Holland (52 o N) high haze high haze low haze reference Dueck et al., 29 [direct] radiation at various latitudes total solar radiation, MJ/m 2 month direct/total radiation 1 Tucson 32 N Bari 8 De Bilt 41 N 6 52 N inverno primavera estate autunno

3 Workshop sustainable greenhouse 3 Ventilation design Ventilation is the cheapest way to get rid of excess sun energy Ventilation capacity must be enough for worst case (summer conditions) inside effect of ventilation upon With limited ventilation capacity sometimes it closed =f(climate & cover is necessary properties) to reduce starting Temperature with reduced transmissivity ventilation capacity external ventilation rate Effect of roof slope on ventilation rate Ventilation flow (m 3 /s) Q = 5,62v R 2 =,96 Q = 5,28v R 2 =,97 Q = 4,46v R 2 =,96 Q = 2,95v R 2 =, Wind speed (m/s) Roof slope: 12 º Roof slope 25 º Roof slope 18 º Roof slope 3 º Baeza, 27 Suggestions to improve windward ventilation Use of deflectors at least in the first spans Minimum roof slope 25 º Limit the greenhouse width to 5-6 m Baeza, 27 m/s Innovative designs being evaluated

4 Workshop sustainable greenhouse 4 Condensation = light loss (~9%) Large slope prevents dripping on the crop Anti-drop surface coating would minimize light loss So would a [diffusing] glass surface structure Stanghellini et al., 21 Examples L effetto della ventilazione sulla temperatura decreasing resource use = smart design cover materials ventilation capacity decreasing waste = process management ventilation thermal storage irrigation management evaluation of means for decreasing environmental impact of passive greenhouses without ventilation (climate & cover properties) desired external actual ventilation ventilation rate needed ventilation Ventilation management = regulable openings o C4 temperatura unventilated serra non ventilata greenhouse 6 temperatura ventilated serra molto greenhouse ventilata outside temperatura fuori W/m 2 sun radiazione radiation (W/m 2 ) Thermal storage too hot management range of ventilation 15 19/1/28 : 19/1/28 12: 2/1/28 : 2/1/28 12: 21/1/28 : time (1 year or 1 day) too cold.. ideal greenhouse external

5 Workshop sustainable greenhouse 5 Active thermal storage Effect of thermal storage on air heating cooling Utilization Storage of of warm water Low- storage In [underground] water basins, natural or artificial With PERFECT storage a greenhouse has a yearly surplus of energy, EVEN at Dutch latitudes and thus much TOO MUCH surplus at lower latitudes! semi-closed greenhouses Temperature, C closed greenhouse outside open greenhouse time Time, of hday please attend the lecture by Esteban Baeza Passive thermal storage o C air temperatura serra soil temperatura suolo Smart irrigation = less emissions less need for fertilisers Fertilisers costs exceed 1% of production costs in Almeria or even 17% in Hungary (Cajamar, 29; Euphoros consortium, 21) /1/28 6: 19/1/28 6: 2/1/28 6: 21/1/28 6: 22/1/28 6: Yet growers are not exactly eager to adopt smart irrigation (Cuadrado Gomez, 21; Euphoros consortium, 21) Smart irrigation in soil = water on demand Closed vs open cycle tomato (Italy) Euphoros consortium, Incrocci, Pisa university: 21 Leaching Supply Saving Open Closed % Water m 3 ha N kg ha P kg ha K kg ha Treatment Water Use (mm) Fertilizer (KgN/ha) Mean Crop Weight (g) Class 1 (%) A (ref) B C D Irrigation was sensordriven and soil water content was controlled to prevent leaching FLOW-AID consortium, 21 (EU-FP6) Investment could be recovered in 2 years Thereafter a saving of some 35 /years Yet Fear of untested techniques Poor faith in advisory services Concern for root pathologies The grower won t do it unless required by regulations

6 Workshop sustainable greenhouse 6 Examples decreasing resource use = smart design cover materials ventilation capacity decreasing waste = process management ventilation thermal storage irrigation management evaluation of means for decreasing environmental impact of passive greenhouses Cumulative evaluation of environmental impact Various production systems/countries Most promising actions = decreased environmental impact coupled to financial gain Implementation in local conditions to evaluate production We have determined the environmental impact of the new technologies Through Life Cycle Analysis we calculated the decrease of environmental footprint per unit product Diminuzione dell impatto ambientale Tomato production in a multitunnel in Almeria Reducing fertilisers by 3% Closed loop irrigation New greenhouse with improved ventilation Abiotic depletion Acidificat Eutrophicat Global warming Photoch. oxidation Cumulative energy Conclusion There is a strong potential for emission reductions by improving the use of natural resources: particularly sunlight and sun energy This is facilitated by technology: innovative structures; process control means Other [recycling] technologies are leading towards the zero emissions greenhouse (not discussed here) Sustainability is based on three linked issues: environment, economics and social concerns Nothing is achieved until new methods are adopted by growers M.Torrellas, A. Antón, E. Baeza, J.C. López, J. Pérez Parra, M. Ruijs, N. García, J.I. Montero, 211 Thanks to: Jos Balendonck, Wageningen, NL Silke Hemming, Wageningen, NL Esteban Baeza, EEFC, ES Juan Ignacio Montero, IRTA, ES Luca Incrocci, Università of Pisa, IT Questions?