Michel Verheul
Senior Research Scientist
(+47) 934 08 525
michel.verheul@nibio.no
Place
Særheim
Visiting address
Postvegen 213, NO-4353 Klepp stasjon
Abstract
Greenhouse cultivation can help meet food demand in a growing and increasingly urbanised population. Reliance on fossil-fuel heating and natural ventilation often makes conventional greenhouses energy- and carbon-inefficient. Closed greenhouses address these limitations through resource recycling and energy recovery. While a centralised environmental control system (ECS) integrating climate control and heat harvesting has shown potential to improve greenhouse crop performance at high latitudes, its year-round energy use and energy-related carbon footprint reduction potential remains insufficiently quantified. This study extends an existing dynamic greenhouse climate model to incorporate a novel centralised ECS integrating air recirculation, heating, cooling, and heat harvesting in (semi-)closed greenhouses. The model was validated using experimental data from Norway, reproducing temperature and relative humidity with RMSEs of 1.40–1.63 °C and 7.60–8.55%, respectively. Energy use and tomato yield were predicted with relative errors of 3.8–8.4% and 1.6–4.2%, respectively. Scenario simulations under Norwegian conditions showed that (semi-)closed greenhouses with heat harvesting can reduce fossil fuel use by over 80% while increasing tomato yields by 15–41% relative to open greenhouses, driven by changes in CO2 concentration and temperature following reduced ventilation and heat recovery. The performance of a fully closed greenhouse relying solely on on-site cold storage is constrained by cooling capacity and buffer size, particularly during summer; adding a supplemental cold energy source such as surface water can improve its performance. Despite heat harvesting, a residual boiler heating demand of 3–10% remains. Further gains in energy efficiency and crop performance may be achieved through optimised climate control.
Abstract
Greenhouse tomato production at high latitudes requires substantial inputs of supplemental lighting, heating and climate control. (Semi-) closed greenhouses can improve heat, water and CO₂ retention, but require additional electricity, climate control system capacities and investment. Crop productivity and resource use must therefore be evaluated jointly. This paper presents the EFREE-Green systems framework for integrating local production conditions, greenhouse environmental control, crop physiological responses, resource flows, and economic and environmental performance. The framework is implemented in two experimental greenhouse compartments operating at a semi-commercial scale at NIBIO Særheim, Norway, connected to a centralized environmental control system (ECS). Measurements at leaf, canopy and greenhouse scale link environmental control with crop carbon gain, biomass partitioning, marketable yield and resource use. Illustrative observations demonstrate that crop responses to supplemental lighting depend on interactions among light availability, CO₂ supply and climate management. Experimental measurements, modelling, techno-economic assessment and life-cycle assessment are combined to evaluate crop productivity, energy efficiency, resource recovery, production costs and greenhouse gas emissions. The framework is transferable to other climatic and production settings, but optimal technologies, capacities and control strategies remain location-specific.
Abstract
EUs kommende forbud mot gummigranulat i kunstgressbaner gjør det ikke bare nødvendig å utvikle alternative fyllmaterialer og kunstgressløsninger, men aktualiserer også bruken av Norges rundt 1500 naturgressbaner for fotball. De viktigste begrensninger for økt bruk av naturgress i Norges er for lite lys og for lav temperatur i 4-8 månder av året avhengig av landsdel. På mange baner vil dessuten mangelen på lys forsterkes av skygge fra tribuneanlegg. Den relative betydningen av lys som veskthemmende faktor forventres å øke i framtida, siden denne, i motsetning til temperatur, ikke påvirkes av klimaendringene. Gressets fotosyntese utnytter lysets bølgelengder i området 400-700 nm, og engrapp, flerårig raigras og andre gressarter på norske fotballbaner krever en daglig lysmengde (DLI, daily light integral) i dette området på minimum 8-12 mol m-2d-1 for å gi akseptabel vekst og slitestyrke. LED-belysning (Light Emitting Diodes) med riktig forhold mellom rødt og blått lys gir bedre vekst, større slitestyrke og inntil 40% lavere energiforbruk enn tradisjonelle lyskilder som HPS (High Pressure Sodium)-lamper. En annen fordel med LED er at det er mulig å tilpasse ikke bare DLI, men også lyskvaliteten (spektralsammensetningen) som påvirker gresskvaliteten. På denne måten kan gresskvaliteten tilpasses sesong, værforhold, gressart og brukintensitet. Kombinert med sensorstyrt undervarme basert på jordvarme eller andre miljøvennlige energikilder legger dermed LED til rette for økt bruk av naturgress. Rapporten gir konkrete eksempler på fleksible styringssystemer for mer optimal ressursbruk og bærekraftig drift av naturgressbaner. Vi forslår at NIBIO bør bygge i et pilotanlegg på Landvik eller Særheim for videre forsking på optimale kombinasjoner og smartere styringssystemer for lys og undervarme på naturgressbaner som alternativ til kunstgress.
