Third order energy chain analysis of hydrogen cars

Norge har som mål om å redusere utslippet av klimagasser med minst 50% i 2030 sammenlignet med utslippsnivået i 1990 (Miljøstatus, 2021b). Utslippet fra veitrafikken utgjør ca. 17% av utslippene i Norge i dag (Miljøstatus, 2021c), og er da en sektor som må redusere utslippene sine for at Norge skal kunne nå klimamålet sitt. En mulighet for å redusere utslipp fra veitrafikken er å bytte ut dagens bensin og dieselpersonbiler med personbiler som benytter alternative drivstoff og har lavere utslipp. Dette inkluderer blant annet elbiler, hydrogenbiler og biler som benytter en hybridløsning mellom fossilt drivstoff og strøm. Fordelen med elbiler og hydrogenbiler er at de ikke har noe utslipp av klimagasser under selve kjøringen av personbilen i motsetning til konvensjonelle biler og hybridbiler som vil ha utslipp av klimagasser. Problemstillingene i denne oppgaven er: Kan hydrogen som drivstoff til personbiler bidra til å redusere utslipp av klimagasser fra persontransport? Hvilken måte å produsere hydrogen på vil føre til de laveste utslippene og hvordan kommer hydrogen ut sammenliknet med elbiler og hybridbil? For å besvare problemstillingen benyttes energikjedeanalyse. Ved å bruke energikjedeanalyse er det mulig å beregne det totale energiforbruket i energikjedene. Det totale energibruket i kjedene er her definert som summen av energibruk fra utvinning av en energikilde til bruk i kjøretøyet, også kalt WTW, og energibruk til produksjon av kjøretøy, batterier og fremdriftssystem. Ved å finne det totale energiforbruket er det mulig å beregne det totale klimagassutslippet, som vil være hovedfokuset i denne oppgaven. De totale energimengdene som kreves i hver energikjedene er interessante å belyse, men de blir først og fremst brukt som en nødvendig mellomregning for å finne klimagassutslippet fra energikjedene. Totalt så tar oppgaven for seg 8 ulike energikjeder, som er kort beskrevet i Tabell 1. Av energikjedene benytter fire personbiler hydrogen som drivstoff, en benytter både strøm og bensin, altså en hybridbil, og de resterende tre energikjedene benytter strøm. I oppgaven er det lagt til grunn fire strømmikser: EU strømmiksen, en fossil strømmiks, en fornybar strømmiks og den norske strømmiksen. Det ble også utført følsomhets- og scenarioanalyser for energikjedene i oppgaven.Norway has a goal to reduce the country’s climate gas emissions by at least 50% in 2030, compared to the country’s emission levels in 1990 (Miljøstatus, 2021b). Emissions from the road traffic sector account for around 17% of total present emissions (Miljøstatus, 2021c), thus the emissions from this sector have to be reduced in order for Norway to meet its climate target. One way of reducing emissions from the road traffic sector is by replacing gasoline and diesel cars with cars that use alternative fuels. This includes electric cars, hydrogen cars or hybrid cars, which use both gasoline and electricity as fuel. The advantage with electric cars and hydrogen cars is that they do not emit emissions while driving, in contrast to gasoline cars, diesel cars and hybrid cars. The aim of this thesis is to answer the following questions: Can hydron as a fuel contribute to reducing emissions of greenhouse gasses from passenger transport? Which ways of producing hydrogen will lead to the lowest emissions and how are these compared to electric cars and hybrid car? To answer this question energy chain analysis is used. By using energy chain analysis it is possible to calculate the total amount of energy used in each energy chain. The total energy amount in each chain is here defined as the sum of the energy used from the extraction of an energy source to its usage in a passenger vehicle, also called WTW, as well as the energy used in the production of the vehicle, batteries and propulsion system. By finding the total energy consumption it is possible to calculate the total greenhouse gas emissions, which will be the main focus in this thesis. The total energy amounts required in each energy chain are interesting to illuminate but are first and foremost used as a necessary between calculation to find the greenhouse gas emissions from the energy chains. Eight different energy chains are included within this thesis, these are presented in Table 2. Four of which used hydrogen as fuel, one is hybrid and thus uses both electricity and gasoline, and the remaining three use electricity as their fuel. The thesis uses four different electricity mixes: an EU electricity mix, a fossil electricity mix, a renewable electricity mix and the Norwegian electricity mix. Multiple sensitivity and scenario analyses were performed within this study as well.M-FORN

Artificial top-light is more efficient for tomato production than inter-light

Studies of whole-plant responses of tomato to light environments are limited and cannot be extrapolated from observations of seedlings or short-term crops in growth chambers. Effects of artificial light sources like high pressure sodium (HPS) and light emitting diodes (LED) are mainly studied as supplement to sunlight in greenhouses. Since natural sunlight is almost neglectable in Norway during wintertime, we could study effects of different types of artificial light on crop growth and production in tomato. The goal of this experiment was to quantify the effects of artificial HPS top-light, installed at the top of the canopy, and LED inter-light, installed between plant rows, on fresh and dry matter production and fruit quality of greenhouse tomatoes under controlled and documented conditions. Our aim was to optimize yield under different light conditions, while avoiding an unfavourable source-sink balance. Tomato plants were grown under HPS top light with an installed capacity of 161, 242 and 272 W m−2 combined with LED inter-light with an installed capacity of 0, 60 or 120 W m−2. We used stem diameter as a trait to regulate air temperature in different light treatments in order to retain plant vigour. Results show that both HPS top light and LED inter-light increased tomato yield. However, the positive effect of supplemental LED inter-light decreased at higher amounts of HPS top light. Under the conditions in this experiment, with neglectable incoming solar radiation, an installed amount of 242 Watt m-2 HPS top light and a daily light integral (DLI) of 30 mol m-2 day-1 resulted in best light use efficiency (in gram fresh tomato per mol). Addition of LED inter-light to HPS top light reduced light use efficiency. Results show that winter production using artificial light in Norway is more energy efficient compared to production under sunlight in southern countries. Results can be used for modelling purposes.acceptedVersio

Vurdering av avrenningsvann i veksthusgrønnsaker

Dagens produksjonsmetode av veksthusgrønnsaker gir betydelig utslipp av næringsstoffer. Det er en situasjon som er uønsket og kan føre til forurensing av nærmiljøet, bruk av for mye næringsstoffer og økonomisk tap for produsenter. Registreringer viser at avrenningsprosenter kan variere mellom 30 og 40 % i tomat og agurk. Tapet av næringsstoffer ble estimert. Det ble påvist at det er mulig å begrense mengde avrenningsvann ved å tilpasse vanningsteknikk. Men bruk av denne vanningsteknikken forutsetter at vanntilførselen er 100% nøyaktig. Avvik vil ha store konsekvenser for avling og/eller kvalitet av produktene og dermed for økonomien for den enkelte produsent, og er dermed enda ikke forsvarlig. Resirkulering av avrenningsvann er teknisk mulig. Det vil redusere avrenningen med tilnærmet 100%. Desinfeksjon av avrenningsvann er helt nødvendige for å unngå spredning av sykdommer. Det er god erfaring med gode teknikker fra utlandet, og teknikkene er beskrevet i rapporten. Resirkulering vil kreve en investering i bl.a. oppsamlingstanker, rensesystemer og en ny gjødselblander. Denne investeringen vil øke produksjonskostnader for gartnerier med et gjennomsnittsareal på 1000-3000 m2 med ca 25 %. Besparelsen av utgifter for gjødsling og vann er estimert på 0,10 til 0,15 nok/kg. Rapporten konkluderer at det er pr i dag for de fleste bedrifter ulønnsom å investere i et slikt vanningssystem

Tredjegrads energikjedeanalyse av hydrogenbiler

Norge har som mål om å redusere utslippet av klimagasser med minst 50% i 2030 sammenlignet med utslippsnivået i 1990 (Miljøstatus, 2021b). Utslippet fra veitrafikken utgjør ca. 17% av utslippene i Norge i dag (Miljøstatus, 2021c), og er da en sektor som må redusere utslippene sine for at Norge skal kunne nå klimamålet sitt. En mulighet for å redusere utslipp fra veitrafikken er å bytte ut dagens bensin og dieselpersonbiler med personbiler som benytter alternative drivstoff og har lavere utslipp. Dette inkluderer blant annet elbiler, hydrogenbiler og biler som benytter en hybridløsning mellom fossilt drivstoff og strøm. Fordelen med elbiler og hydrogenbiler er at de ikke har noe utslipp av klimagasser under selve kjøringen av personbilen i motsetning til konvensjonelle biler og hybridbiler som vil ha utslipp av klimagasser. Problemstillingene i denne oppgaven er: Kan hydrogen som drivstoff til personbiler bidra til å redusere utslipp av klimagasser fra persontransport? Hvilken måte å produsere hydrogen på vil føre til de laveste utslippene og hvordan kommer hydrogen ut sammenliknet med elbiler og hybridbil? For å besvare problemstillingen benyttes energikjedeanalyse. Ved å bruke energikjedeanalyse er det mulig å beregne det totale energiforbruket i energikjedene. Det totale energibruket i kjedene er her definert som summen av energibruk fra utvinning av en energikilde til bruk i kjøretøyet, også kalt WTW, og energibruk til produksjon av kjøretøy, batterier og fremdriftssystem. Ved å finne det totale energiforbruket er det mulig å beregne det totale klimagassutslippet, som vil være hovedfokuset i denne oppgaven. De totale energimengdene som kreves i hver energikjedene er interessante å belyse, men de blir først og fremst brukt som en nødvendig mellomregning for å finne klimagassutslippet fra energikjedene. Totalt så tar oppgaven for seg 8 ulike energikjeder, som er kort beskrevet i Tabell 1. Av energikjedene benytter fire personbiler hydrogen som drivstoff, en benytter både strøm og bensin, altså en hybridbil, og de resterende tre energikjedene benytter strøm. I oppgaven er det lagt til grunn fire strømmikser: EU strømmiksen, en fossil strømmiks, en fornybar strømmiks og den norske strømmiksen. Det ble også utført følsomhets- og scenarioanalyser for energikjedene i oppgaven

Bioeconomic evaluation of extended season and year-round tomato production in Norway using supplemental light

CONTEXT For high latitude countries like Norway, one of the biggest challenges associated with greenhouse production is the limited availability of natural light and heat, particularly in winters. This can be addressed by changes in greenhouse design elements including energy saving equipment and supplemental lighting, which, however, also can have a huge impact on investments, economic performance, resources used and environmental consequences of the production. OBJECTIVE The study aimed at identifying a greenhouse design from a number of feasible designs that generated highest Net Financial Return (NFR) and lowest fossil fuel use for extended seasonal (20th January to 20th November) and year-round tomato production in Norway using different capacities of supplemental light sources as High Pressure Sodium (HPS) and Light Emitting Diodes (LED), heating from fossil fuel and electricity sources and thermal screens by implementing a recently developed model for greenhouse climate, tomato growth and economic performance. METHODS The model was first validated against indoor climate and tomato yield data from two commercial greenhouses and then applied to predict the NFR and fossil fuel use for four locations: Kise in eastern Norway, Mære in mid Norway, Orre in southwestern Norway and Tromsø in northern Norway. The CO2 emissions for natural gas used for heating the greenhouse and electricity used for lighting were calculated per year, unit fruit yield and per unit of cultivated area. A local sensitivity analysis (LSA) and a global sensitivity analysis (GSA) were performed by simultaneously varying the energy and tomato prices. RESULTS AND CONCLUSIONS Across designs and locations, the highest NFR for both production cycles was observed in Orre (116.9 NOK m−2 for extended season and 268.5 NOK m−2 for year-round production). Fossil fuel was reduced significantly when greenhouse design included a heat pump and when extended season production was replaced by a year-round production. SIGNIFICANCE The results show that the model is useful in designing greenhouses for improved economic performance and reduced CO2 emissions from fossil fuel use under different climate conditions in high latitude countries. The study aims at contributing to research on greenhouse vegetable production by studying the effects of various designs elements and artificial lighting and is useful for local tomato growers who either plan to build new greenhouses or adapt existing ones and in policy formulation regarding incentivizing certain greenhouse technologies with an environmental consideration or with a focus on increasing local tomato production.publishedVersio

Bio-economic evaluation of greenhouse designs for seasonal tomato production in Norway

Greenhouses are complex systems whose size, shape, construction material, and equipment for climate control, lighting and heating can vary largely. The greenhouse design can, together with the outdoor weather conditions, have a large impact on the economic performance and the environmental consequences of the production. The aim of this study was to identify a greenhouse design out of several feasible designs that generated the highest net financial return (NFR) and lowest energy use for seasonal tomato production across Norway. A model-based greenhouse design method, which includes a module for greenhouse indoor climate, a crop growth module for yield prediction, and an economic module, was applied to predict the NFR and energy use. Observed indoor climate and tomato yield were predicted using the climate and growth modules in a commercial greenhouse in southwestern Norway (SW) with rail and grow heating pipes, glass cover, energy screens, and CO2-enrichment. Subsequently, the NFR and fossil fuel use of five combinations of these elements relevant to Norwegian conditions were determined for four locations: Kise in eastern Norway (E), Mære in midwestern Norway (MW), Orre in southwestern Norway (SW) and Tromsø in northern Norway (N). Across designs and locations, the highest NFR was 47.6 NOK m−2 for the greenhouse design with a night energy screen. The greenhouse design with day and night energy screens, fogging and mechanical cooling and heating having the lowest fossil energy used per m2 in all locations had an NFR of −94.8 NOK m−2. The model can be adapted for different climatic conditions using a variation in the design elements. The study is useful at the practical and policy level since it combines the economic module with the environmental impact to measure CO2 emissions.publishedVersio

Bioeconomic evaluation of extended season and year-round tomato production in Norway using supplemental light

CONTEXT For high latitude countries like Norway, one of the biggest challenges associated with greenhouse production is the limited availability of natural light and heat, particularly in winters. This can be addressed by changes in greenhouse design elements including energy saving equipment and supplemental lighting, which, however, also can have a huge impact on investments, economic performance, resources used and environmental consequences of the production. OBJECTIVE The study aimed at identifying a greenhouse design from a number of feasible designs that generated highest Net Financial Return (NFR) and lowest fossil fuel use for extended seasonal (20th January to 20th November) and year-round tomato production in Norway using different capacities of supplemental light sources as High Pressure Sodium (HPS) and Light Emitting Diodes (LED), heating from fossil fuel and electricity sources and thermal screens by implementing a recently developed model for greenhouse climate, tomato growth and economic performance. METHODS The model was first validated against indoor climate and tomato yield data from two commercial greenhouses and then applied to predict the NFR and fossil fuel use for four locations: Kise in eastern Norway, Mære in mid Norway, Orre in southwestern Norway and Tromsø in northern Norway. The CO2 emissions for natural gas used for heating the greenhouse and electricity used for lighting were calculated per year, unit fruit yield and per unit of cultivated area. A local sensitivity analysis (LSA) and a global sensitivity analysis (GSA) were performed by simultaneously varying the energy and tomato prices. RESULTS AND CONCLUSIONS Across designs and locations, the highest NFR for both production cycles was observed in Orre (116.9 NOK m−2 for extended season and 268.5 NOK m−2 for year-round production). Fossil fuel was reduced significantly when greenhouse design included a heat pump and when extended season production was replaced by a year-round production. SIGNIFICANCE The results show that the model is useful in designing greenhouses for improved economic performance and reduced CO2 emissions from fossil fuel use under different climate conditions in high latitude countries. The study aims at contributing to research on greenhouse vegetable production by studying the effects of various designs elements and artificial lighting and is useful for local tomato growers who either plan to build new greenhouses or adapt existing ones and in policy formulation regarding incentivizing certain greenhouse technologies with an environmental consideration or with a focus on increasing local tomato production

Bio-economic evaluation of greenhouse designs for seasonal tomato production in Norway

Greenhouses are complex systems whose size, shape, construction material, and equipment for climate control, lighting and heating can vary largely. The greenhouse design can, together with the outdoor weather conditions, have a large impact on the economic performance and the environmental consequences of the production. The aim of this study was to identify a greenhouse design out of several feasible designs that generated the highest net financial return (NFR) and lowest energy use for seasonal tomato production across Norway. A model-based greenhouse design method, which includes a module for greenhouse indoor climate, a crop growth module for yield prediction, and an economic module, was applied to predict the NFR and energy use. Observed indoor climate and tomato yield were predicted using the climate and growth modules in a commercial greenhouse in southwestern Norway (SW) with rail and grow heating pipes, glass cover, energy screens, and CO2-enrichment. Subsequently, the NFR and fossil fuel use of five combinations of these elements relevant to Norwegian conditions were determined for four locations: Kise in eastern Norway (E), Mære in midwestern Norway (MW), Orre in southwestern Norway (SW) and Tromsø in northern Norway (N). Across designs and locations, the highest NFR was 47.6 NOK m−2 for the greenhouse design with a night energy screen. The greenhouse design with day and night energy screens, fogging and mechanical cooling and heating having the lowest fossil energy used per m2 in all locations had an NFR of −94.8 NOK m−2. The model can be adapted for different climatic conditions using a variation in the design elements. The study is useful at the practical and policy level since it combines the economic module with the environmental impact to measure CO2 emissions

A greenhouse climate-yield model focussing on additional light, heat harvesting and its validation

A greenhouse climate-crop yield model was adapted to include additional climate modification techniques suitable for enabling sustainable greenhouse management at high latitudes. Additions to the model were supplementary lighting, secondary heating and heat harvesting technologies. The model: 1) included the impact of different light sources on greenhouse air temperature and tomato production 2) included a secondary heating system 3) calculated the amount of harvested heat whilst lighting was used. The crop yield model was not modified but it was validated for growing tomato in a semi-closed greenhouse equipped with HPS lamps (top-lights) and LED (inter-lights) in Norway. The combined climate-yield model was validated with data from a commercial greenhouse in Norway. The results showed that the model was able to predict the air temperature with sufficient accuracy during the validation periods with Relative Root Mean Square Error <10%. Tomato yield was accurately simulated in the cases under investigation, yielding a final production difference between 0.7% and 4.3%. Lack of suitable data prevented validation of the heat harvest sub-model, but a scenario is presented calculating the maximum harvestable heat in an illuminated greenhouse. Given the cumulative energy used for heating, the total amount of heating pipe energy which could be fulfilled with the heat harvestable from the greenhouse air was around 50%. Given the overall results, the greenhouse climate(-crop yield) model modified and presented in this study is considered accurate enough to support decisions about investments at farm level and/or evaluate beforehand the possible consequences of environmental policies