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Tilgang på fornybar energi for sjømatnæringen fram mot 2040 Hovedfunn og konklusjoner fra EnerSea-prosjektet (FHF-901866)
Get PDFEnerSea-prosjektet har som hovedmål å dokumentere sjømatnæringens behov for og fremtidig tilgang på fornybar energi fram mot 2040, barrierer for nettilgang og alternative energikilder og -bærere. Hovedfokus har vært hvordan sjømatnæringen kan få tilgang til fornybar energi, hovedsakelig ved hjelp av raskere nettilknytning, men det er også gjort en vurdering av alternative energikilder og -bærere. Denne rapporten gir et sammendrag av hovedfunnene fra prosjektets tre delrapporter.Tilgang på fornybar energi for sjømatnæringen fram mot 2040 Hovedfunn og konklusjoner fra EnerSea-prosjektet (FHF-901866)publishedVersio
Experimental investigation of simultaneous nitrification-denitrification and phosphorus removal in pilot-scale sequencing batch moving bed biofilm reactors (SB-MBBRs)
Get PDFSequencing batch moving bed biofilm reactors have been widely used in commercial wastewater treatment facilities for organic carbon and nitrogen removal. However, these reactors can remove low phosphorus (P) levels. Therefore, this study investigated the potential of SB-MBBRs for maximizing simultaneous nitrification-denitrification and P removal (SNDPR) potential from P-rich municipal wastewater impacted by industrial discharges. A series of experiments were carried out to investigate the effect of external volatile fatty acid (VFA) dosing, airflow rate, and temperature on SNDPR using pilot-scale SBMBBRs. Stable and robust SNDPR was achieved with an optimum acetic acid supply of 150 mg SCOD/L, at 20 oC and 2.5 L air/min. A low airflow rate (AFR) and high-temperature conditions affected P release and uptake kinetics. Efficient PHA storage, dissolved oxygen (DO) transfer (outer layer), DO diffusion limitation (inner layer) of biofilm, and conversion of NH4-N to NO2-N/NO3-N enhanced SNDPR in the two pilot SB-MBBRs.publishedVersio
Road user opinions and needs regarding small modular autonomous electric vehicles: Differences between elderly and non-elderly in Norway
Get PDFThis study examines road user opinions regarding small modular autonomous electric vehicles, focusing on the differences between the elderly and non-elderly populations in Norway. The data allowed for a comparison between 193 respondents under 65 years old and 208 respondents over 65 years old. The results highlighted significant differences between the two groups about the vehicles, their usability, and the likeliness of using them as public transport if implemented in the future. Traffic safety and personal security were found to be decisive aspects, for respondents over 65 years old being more worried about safety and security than their counterparts. Trust that the authorities will ensure the safe implementation of such vehicles in the current transportation system was also significantly different between the two groups, with the younger generations having more trust in the authorities than the older group. The results shed light on road user opinions about a small modular transport mode, particularly on those over 65 years old, indicating a need for research efforts to better identify how this new form of public transport should be implemented in the future to improve the mobility of all travellers and meet the needs of the seniors.publishedVersio
Pseudo-Hamiltonian neural networks for learning partial differential equations
Get PDFPseudo-Hamiltonian neural networks (PHNN) were recently introduced for learning dynamical systems that can be modelled by ordinary differential equations. In this paper, we extend the method to partial differential equations. The resulting model is comprised of up to three neural networks, modelling terms representing conservation, dissipation and external forces, and discrete convolution operators that can either be learned or be given as input. We demonstrate numerically the superior performance of PHNN compared to a baseline model that models the full dynamics by a single neural network. Moreover, since the PHNN model consists of three parts with different physical interpretations, these can be studied separately to gain insight into the system, and the learned model is applicable also if external forces are removed or changed.publishedVersio
Using ProdRisk–SHOP Simulator for Investment Decisions of Solar and Hydro Hybridization
Get PDFThis paper uses two scheduling tools to compare the economic performance and production outcomes of three investment alternatives in a Norwegian hydropower plant. The investment options considered are 1) Hybridization with Floating Photovoltaics (FPV), 2) Incorporation of an additional creek inlet to the reservoir, and 3) Enhancement of the generator capacity. Specifically, we utilize a short-term deterministic optimization model (SHOP) and a simulator that integrates the deterministic model with a mid-term stochastic model (ProdRisk-SHOP Simulator). Based on 24 years of historical inflow data, market prices, and simulated 10-MWp FPV production from 2000 to 2023, the numerical results of both tools indicate that the additional creek inlet option yields the highest average economic returns, followed by the hybrid configuration. While the upgraded capacity scenario results in the lowest average annual profit, it capitalizes on volatile market conditions by maximizing production during price spikes. ProdRisk-SHOP Simulator outperforms SHOP regarding resource management since in SHOP, the initial and end reservoir water levels are predetermined, whereas in the simulator, they are part of the optimization.Using ProdRisk–SHOP Simulator for Investment Decisions of Solar and Hydro HybridizationacceptedVersio
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Onboard carbon capture and storage (OCCS) for fossil fuel-based shipping: A sustainability assessment
Get PDFLimiting the carbon intensity of maritime transport is crucial to meet 2050 net-zero targets. Onboard carbon capture and storage (OCCS) offers a practical short-term solution for reducing shipping-related CO2 emissions until cleaner technologies are ready for large-scale adoption. This study introduces an innovative multi-objective approach to integrate sustainability into the conceptual design and decision-making phases of OCCS. A systematic technology screening identified possible OCCS solutions, which were then assessed for onboard feasibility. Specific indicators were defined to evaluate OCCS performance based on technological, economic, environmental, and social criteria, and aggregated sustainability perspectives. Using a fossil fuel-powered cruise ship as a case study, results were benchmarked against zero-carbon alternatives. Among the alternatives considered, chemical absorption by amine scrubbing (AS) and advanced cryogenic carbon capture (A3C) appeared as the only feasible solutions considering onboard energy requirements. The emerging cryogenic A3C concept resulted in being outperformed by benchmark AS, primarily due to an environmental impact 1.5 times higher. All alternative technologies, whether OCCS- or cleaner fuel-based, were found to be more sustainable than the baseline fossil fuel-based engine, lowering the environmental impact by at least 61%. Hydrogen as a marine fuel leads to the most promising scenario for future cleaner shipping operations, reducing the sustainability footprint by up to 76%. The robustness of the proposed method was confirmed by a probabilistic Monte Carlo sensitivity analysis. Overall, the results obtained can guide toward more informed solutions and policies promoting the sustainability of ship propulsion systems. © 2024 The AuthorspublishedVersio
Environmental Impact of Enhanced Geothermal Systems with Supercritical Carbon Dioxide: A Comparative Life Cycle Analysis of Polish and Norwegian Cases
Get PDFLow-carbon electricity and heat production is essential for keeping the decarbonization targets and climate mitigation goals. Thus, an accurate understanding of the potential environmental impacts constitutes a key aspect not only for the reduction in greenhouse gas emissions but also for other environmental categories. Life cycle assessment allows us to conduct an overall evaluation of a given process or system through its whole lifetime across various environmental indicators. This study focused on construction, operation and maintenance, and end-of-life phases, which were analyzed based on the ReCiPe 2016 method. Within this work, authors assessed the environmental performance of one of the renewable energy sources—Enhanced Geothermal Systems, which utilize supercritical carbon dioxide as a working fluid to produce electricity and heat. Heat for the process is extracted from hot, dry rocks, typically located at depths of approximately 4–5 km, and requires appropriate stimulation to enable fluid flow. Consequently, drilling and site preparation entail significant energy and material inputs. This stage, based on conducted calculations, exhibits the highest global warming potential, with values between 5.2 and 30.1 kgCO2eq/MWhel, corresponding to approximately 65%, 86%, and 94% in terms of overall impacts for ecosystems, human health, and resources categories, respectively. Moreover, the study authors compared the EGS impacts for the Polish and Norwegian conditions. Obtained results indicated that due to much higher electricity output from the Norwegian plant, which is sited offshore, the environmental influence remains the lowest, at a level of 11.9 kgCO2eq/MWhel. Polish cases range between 38.7 and 54.1 kgCO2eq/MWhel of global warming potential in terms of electricity production. Regarding power generation only, the impacts in the case of the Norwegian facility are two to five times lower than for the installation in the Polish conditions. Keywords: enhanced geothermal systems; supercritical carbon dioxide cycles; life cycle assessment; geothermal energy; environmental performancepublishedVersio
