Results 11 - 20 of 1916
Results 11 - 20 of 1916. Search took: 0.029 seconds
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[en] Highlights: • A multi-objective MPC strategy for residential heating with heat pumps is presented. • The simulations employ detailed models for heat pump and thermal energy storage. • The feedback of individual controllers on the electricity generation is included. • Results show a significant reduction in required generation capacity is possible. • Costs carried by the consumer rise when demand response is applied. - Abstract: Shifting residential space heating from the use of gas boilers towards the use of heat pumps is recognized as a method to reduce green house gas emissions and increase energy efficiency and the share of renewable energy sources. Demand response of these systems could aid in reducing peak loads on the electricity grid. Extra flexibility can be added in the form of a thermal energy storage tank. This paper proposes a multi-objective model predictive control strategy for such a system, which takes into account the users energy cost, the environmental impact of energy use and the impact of expanding the electricity generation capacity. This control strategy is used in a case study inspired by the Belgian electricity generation park with 500,000 heat pumps to investigate the effect of the size of a space heating storage tank on consumer cost, energy use and required electricity generation capacity. Results indicate that the proposed demand response strategy reduces the required peak load capacity substantially with only a small increase in costs for the consumer. When adding a large hot water storage tank, the required additional capacity is nearly eliminated. Independently of the required capacity, the controller shifts energy use from peak to base generating plants. Increasing the storage tank size increases the amount of energy that is shifted. However, when demand response is applied by using a space heating storage tank, the costs for the consumer always increase relative to the case without demand response or storage tank. If demand response is desired by the grid operator, heat pump owners should be encouraged to participate by remunerating them for their additional expenses.
[en] There is clear evidence of rising levels of carbon dioxide in the atmosphere caused by the profligate use of energy by the industrialised countries. This is threatening global climate change. This, as also continuously depleting fuel resources, is likely to deprive the developing world from meeting its yet unfulfilled development aspirations. Energy is an essential input for development, but growth rate in energy use in any country depends on its current development level. The energy use in the developed countries is projected to grow slowly, while it is growing very fast in the developing countries. It has been the experience of all the countries that development results in a shift from the use of non-commercial energy sources to commercial energy sources, particularly electricity. Thus the developing countries are experiencing a surge in electricity demand, both due to the growth in energy use and shift rom non-commercial to commercial energy sources
[en] We investigate this study to examine the relationship between economic growth, freight transport, and energy consumption for 63 developing countries over the period of 1990–2016. In order to make the panel data analysis more homogeneous, we apply the income level of countries to divide the global panel into three sub-panels, namely, lower-middle income countries (LMIC), upper-middle income countries (UMIC), and high-income countries (HIC). Using the generalized method of moments (GMM), the results prove evidence of bidirectional causal relationship between economic growth and freight transport for all selected panels and between economic growth and energy consumption for the high- and upper-middle income panels. For the lower-middle income panel, the causality is unidirectional running from energy consumption to economic growth. Also, the results indicate that the relationship between freight transport and energy use is bidirectional for the high-income countries and unidirectional from freight transport to energy consumption for the upper-middle and lower-middle income countries. Empirical evidence demonstrates the importance of energy for economic activity and rejects the neo-classical assumption that energy is neutral for growth. An important policy recommendation is that there is need of advancements in vehicle technology which can reduce energy intensity from transport sector and improve the energy efficiency in transport activity which in turn allows a greater positive role of transport in global economic activity.
[en] The German Atomforum (DAtF) and the Kerntechnische Gesellschaft (KTG) held the annular meeting Nuclear Technology from 4th until 6th May 1982 in Mannheim. The structure,which was determined after various changes in the previous year, was retained year and should definitively decisive for further meetings: Three plenary sessions on Tuesday morning and Thursday morning and afternoon, three parallel technical sessions on Wednesday morning, and technical sessions in nine sessions (sections) on Tuesday and Wednesday afternoon. With a cutback to three days, maximum concentration has been achieved for such a wide-ranging meeting. However, an attractive lecture topic and the announcement of the participation of the Federal Minister of the Interior in the final session of the former participants observer on Friday could not prevent the loss of attendance.
[en] This paper discusses the quality of contractor work. Contractors do not consistently work to station standards and expectations. The impact or consequence is that rework causes increase in costs and schedule delays, challenges operations ability to return systems to service and erodes the organizations confidence. Current state or challenges with solving the issue are improvements in supervisory capability and performance, enhanced human performance, focus improvements in outage preparations, improvements in outage execution. In order to solve the issue, improve quality of oversight and improve quality of source documentation used by contractor.
[en] As 2018 draws to a close, there have been several developments that will mean the new year dawning with fresh uncertainties on the horizon for the global nuclear energy industry: Brexit and announcement of the Trump administration for a new policy framework for curtailing civil nuclear commerce with China are two of them.
[en] Ontario Power Generation (OPG) produces almost half of the electricity that Ontario homes, schools, hospitals and businesses rely on each day. With an in-service capacity of 16,218 megawatts, OPG owns and operates a diverse generation fleet that includes: two nuclear stations, 66 hydroelectric stations on 24 river systems, two biomass stations, one thermal station, and one wind turbine. OPG's power is more than 99 per cent free of smog and carbon emissions. Jeff Lehman, Vice President -- New Nuclear Development, will provide an overview of OPG's current operating performance and key projects, including the Darlington Refurbishment project. This presentation will also highlight OPG's involvement in the exploration of future new nuclear development opportunities, including small modular reactor applications.
[en] There has been a rapidly-growing international interest in smaller, simpler reactors for generating electricity and process heat. Interest in a new generation of advanced small modular reactor (SMR) technology has been driven by many factors, including the desire to reduce capital costs, to reduce greenhouse gas emissions, to replace retiring fossil plants that do not meet today's environmental standards, and to provide reliable power in 'off-grid' or 'edge-of-grid' locations. This new generation of low-carbon, GHG-free advanced reactors can be used in remote communities and resource extraction industries to supply safe, reliable and economical energy generation that can help mitigate climate change and help stimulate economic growth. Introduction of these advanced small reactors, particularly in Canada's resource-rich remote northern regions, will raise issues in a wide variety of technical, institutional, socio-economic, and regulatory policy areas. The Emissions-Free Energy Working Group (EFEWG) has been established as a technology-neutral, small-reactor industry-wide organization to identify and prioritize the high-level issues that need to be addressed and work with the CNSC and other interested stakeholders to agree on a resolution acceptable to all parties. By working together as one entity, the industry has an opportunity through the EFWG to influence the development of high-level regulatory policy and the associated regulatory framework and documents as they apply to small reactors in Canada. This will benefit the industry by reaching issue resolutions that are applied uniformly across the SMR industry and by distributing their development costs across the industry. The vision of the EFEWG is a flourishing small reactor industry in Canada within the next 25 years. The approach it is taking is to identify barriers to realizing this vision and to identify measures that can be taken to reduce or transcend those barriers. It will communicate its findings to other stakeholders and will collaborate with them to implement these measures. The philosophy of the EFEWG is to work openly and transparently with regulatory authorities and other stakeholders to ensure that small reactors meet all legitimate public requirements and concerns, with a view to realizing this industry's potential to benefit Canada while maintaining or improving nuclear safety. Among its many activities, the EFEWG has cooperated with the CNSC to hold workshops for provincial and federal government stakeholders on very small reactors in remote northern regions; has prepared a report on the legal and regulatory issues for deployment of factory fuelled and sealed SMRs across international waters from one country to another; and is now conducting a Canadian deployment study for transport of factory fuelled SMRs from one provincial jurisdiction to another. The Emissions-Free Energy Working Group looks forward to continuing its work on behalf of the small-reactor industry and its stakeholders. (author)
[en] Highlights: • A dynamic model of Steam Turbine control valve and actuation systems is proposed. • An innovative study of the equations that rule the assembly movement is provided. • Control valve response and accuracy is analyzed in detail with test and simulation. • System upgrade is achieved with Electro-Hydrostatic Actuation technology. - Abstract: The paper describes a study conducted on the control valve and the actuation systems of a Steam Turbine. These devices are of utmost importance, as they rule the machine final power production and rotational speed, thus their accurate modelling is fundamental for a valuable dynamic analysis of the whole system. In particular, a dynamic model developed in the Matlab/Simulink environment is proposed, which supports the analysis of the operational stability of the hydro-mechanical system as well as the failure modes that it may face during operation. The model has been successfully validated through specific field tests conducted on the actuation system at a cogeneration plant located in the General Electric Oil & Gas - Nuovo Pignone facility of Florence. The proposed work also highlights the requirements that new actuation technologies should fulfill in order to meet control valve system performance criteria and is thus useful as both a methodological approach and a “virtual benchmark” allowing to validate in advance any new actuation system.
[en] Highlights: • Optimization model for BtL production considering competing utilization paths. • Supply chain with decentralized pre-treatment via torrefaction and fast pyrolysis. • Local supply curves are used to model diseconomies of scale in biomass supply. • Synthetic gasoline can be produced at a cost of 0.8–0.9 € per liter. • BtL feedstock costs are 20–50% higher compared with established consumers. - Abstract: Second generation biofuels offer the opportunity to mitigate emissions from the growing transportation sector while respecting the scarcity of arable land in agriculture. Biomass-to-liquid (BtL) concepts based on large-scale gasification are capable of using low-quality residual feedstock, such as wheat straw or forest residues, for the production of transportation fuels. However, large amounts of biomass feedstock are required to achieve the economic capacity of a synthesis plant. Depending on the steepness of the terrain and the role of feedstock owners, biomass potentials can only be utilized to a large extent at increasing costs per ton. Such diseconomies of scale are particularly problematic in the presence of already established value chains consuming the easily accessible and low-cost feedstock. As a result, second-generation biofuel supply chains face steep supply curves with sharply increasing unit costs. This article investigates the impact of established utilization paths on a large-scale biofuel production value chain. To do so, a mixed-integer linear model is presented which first determines the allocation of biomass resources to CHP plants and domestic consumers. Based on the resulting costs and supply curves, the model then determines the optimum configuration of the synfuel supply chain including locations and capacities of conversion plants, feedstock procurement and transportation. The model is applied to a case study covering six regions in south-central Chile. The total supply chain cost for the production of synthetic gasoline is estimated to amount to 0.8–0.9 € per liter. Feedstock costs of the synfuel supply chain are 20–50% higher in comparison to the price paid by CHP plants and households. The results indicate that both torrefaction and fast pyrolysis can be applied beneficially to utilize remote biomass resources which are less in demand by established consumers.