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The objective of this study is to examine the potential for a full transition to domestically produced biofuels in the Stockholm County transport system in 2030, without exceeding the proportional share of national bioenergy assets. This target is chosen in order to test the potential of biofuel assets in Sweden, facilitating the transition to renewable fuel systems, and to display the potential of...
The global electricity supply from non-hydro renewables, mainly wind and solar, is currently growing at a high rate, and it is expected that this trend persists. In the near-to-medium term, the power produced by breakthrough fossil fuel technologies might also grow intensively. These expansion patterns can be optimized in a regional context, which translates into a multidimensional problem. As part...
We have developed a model to generate synthetic sequences of half-hourly electricity demand. The generated sequences represent possible realisations of electricity load that could have occurred. Each of the components included in the model has a physical interpretation. These components are yearly and daily seasonality which were modelled using Fourier series, weekly seasonality modelled with dummy...
This paper analyzes the technical, economic, and environmental characteristics of different pathways for supplying hydrogen to vehicles in China. A life-cycle accounting of “well-to-tank” hydrogen delivery for 11 different infrastructure pathways reveals different relative economic costs and environmental benefits. Coal-derived methanol as a hydrogen carrier appears particularly promising for China...
Energy service business, or energy service company (ESCO), is expanding among industrial users as a means of energy saving. The ESCO business normally tends to become a long-term operation. During the operation, fluctuations of fuel and electricity costs significantly impact on the stability of the profit from ESCO business. Therefore, it is essential to reduce the risk of fuel and electricity cost...
The development of a model for any energy system is required for proper design, operation or its monitoring. Models based on accurate mathematical expressions for physical processes are mostly useful to understand the actual operation of the plant. However, for large systems like combined heat and power (CHP) plants, such models are usually complex in nature. The estimation of output parameters using...
The effects of biodiesel (rapeseed methyl ester, RME) and different diesel/RME blends on the diesel engine NO x emissions, smoke, fuel consumption, engine efficiency, cylinder pressure and net heat release rate are analysed and presented. The combustion of RME as pure fuel or blended with diesel in an unmodified engine results in advanced combustion, reduced ignition delay and increased heat...
In this paper, exergy transfer effectiveness is defined to describe the performance of heat exchangers operating above/below the surrounding temperature with/without finite pressure drop. It is discussed systemically that the effects of heat transfer units number, the ratio of the heat capacity of cold fluids to that of hot fluids and flow patterns on exergy transfer effectiveness of heat exchangers...
Appropriate energy–environment–economic (E3) modelling provides key information for policy makers in the electricity supply industry (ESI) faced with navigating a sustainable development path. Key challenges include engaging with stakeholder values and preferences, and exploring trade-offs between competing objectives in the face of underlying uncertainty. As a case study we represent the South African...
Despite the fact that a stand-alone ideal heat-integrated distillation column (ideal HIDiC) can be thermodynamically efficient and operationally stable, the application of an ideal HIDiC system to separate a close-boiling multi-component mixture is still a challenging problem because of the possibility of strong interactions within/between the ideal HIDiCs involved. In this work, employment of two...
The economic and system measures associated with hydrocarbon development are subject to various levels of private and market uncertainty. The purpose of this paper is to develop an analytic framework to quantify the influence of private and market uncertainty under a concessionary fiscal system. A meta-modeling approach is employed to develop regression models for take and investment criteria in terms...
This paper presents the results of a study that estimated the DSM energy saving and load management potential in commercial and government/institutional sectors in Oman (central grid area) and evaluated its impact on generation capacity and energy savings. The end-use (lighting and air-conditioning) energy consumption data have been collected in two major segments of the commercial sector for simplicity...
Being environmental friendly and with the potential of energy-efficiency, more and more ground-source heat pump (GSHP) systems are being widely used. However, the influence of groundwater advection on the performance of the geothermal heat exchanger (GHE) in a GSHP is not still clearly known. In this paper, the configuration of a vertical dual-function GHE used in an integrated soil cold storage and...
Legislative regulations in favor of combined heat and power (CHP) production have been implemented in many countries. Although these regulations put different emphasis on power production vs. process heat production, they are based on energy quantities and not on exergy. In order to analyze and compare the exergetic consequences of the various legislations, a relative avoided irreversibility (RAI)...
The dividing-wall distillation column is thermodynamically equivalent to the Petlyuk column on the condition that no heat transfer is allowed across the dividing wall. However, better energy efficiency of the column may be obtained if heat transfer occurs within a certain part of the wall. The effects of heat transfer across the dividing wall can be analyzed by using the column grand composite curve...
The critical liquefaction of rice straw to bio-oil with sub- and supercritical mixtures (ethanol–water and 2-propanol–water mixture) was studied in a 1000ml autoclave at 533–623K, 6–18MPa, respectively. The results showed that the maximum yield of bio-oil was 39.7% for the 2-propanol:water volume ratio of 5:5 at 573K, while the higher heating value (HHV) of bio-oil increased with the reaction temperature...
Energy demand of India is continuously increasing. Coal is the major fossil fuel in India and continues to play a pivotal role in the energy sector. India has relatively large reserves of coal (253 billion tonnes) compared to crude oil (728 million tonnes) and natural gas (686 billion cubic meters). Coal meets about 60% of the commercial energy needs and about 70% of the electricity produced in India...
The purpose of the present study is to design a current control system which is robust to the system dynamics uncertainty and the disturbance of ambient temperature to assure a stable optical output property of LED. The system dynamics model of the LED lighting system was first derived. A 96W high-power LED luminaire was designed and built in the present study. The linearly perturbed system dynamics...
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