Hydro-Québec

About: Hydro-Québec is a government organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Electric power system & Dielectric. The organization has 2596 authors who have published 4433 publications receiving 100878 citations.

The role of hydrological model complexity and uncertainty in climate change impact assessment

Abstract: . Little quantitative knowledge is as yet available about the role of hydrological model complexity for climate change impact assessment. This study investigates and compares the varieties of different model response of three hydrological models (PROMET, Hydrotel, HSAMI), each representing a different model complexity in terms of process description, parameter space and spatial and temporal scale. The study is performed in the Ammer watershed, a 709 km2 catchment in the Bavarian alpine forelands, Germany. All models are driven and validated by a 30-year time-series (1971–2000) of observation data. It is expressed by objective functions, that all models, HSAMI and Hydrotel due to calibration, perform almost equally well for runoff simulation over the validation period. Some systematic deviances in the hydrographs and the spatial patterns of hydrologic variables are however quite distinct and thus further discussed. Virtual future climate (2071–2100) is generated by the Canadian Regional Climate Model (vers 3.7.1), driven by the Coupled Global Climate Model (vers. 2) based on an A2 emission scenario (IPCC 2007). The hydrological model performance is evaluated by flow indicators, such as flood frequency, annual 7-day and 30-day low flow and maximum seasonal flows. The modified climatic boundary conditions cause dramatic deviances in hydrologic model response. HSAMI shows tremendous overestimation of evapotranspiration, while Hydrotel and PROMET behave in comparable range. Still, their significant differences, like spatially explicit patterns of summerly water shortage or spring flood intensity, highlight the necessity to extend and quantify the uncertainty discussion in climate change impact analysis towards the remarkable effect of hydrological model complexity. It is obvious that for specific application purposes, water resources managers need to be made aware of this effect and have to take its implications into account for decision making. The paper concludes with an outlook and a proposal for future research necessities.

Amorphous and nanocrystalline Fe–Ti prepared by ball milling

Abstract: Nanocrystalline FeTi has been prepared in two ways: by ball milling the intermetallic compound and mechanically alloying a mixture of the elemental powders. The materials obtained in each case are identical. The reaction proceeds via the formation of interfacial β–Ti(Fe) which then grows to include all of the material present. Oxygen levels above 3 at. % suppress this reaction and lead to the formation of amorphous Fe–Ti.

Environmental impacts of Lithium Metal Polymer and Lithium-ion stationary batteries

Abstract: The installed capacity of stationary batteries is expected to grow rapidly in the coming years. This deployment will have impacts on the environment that must be investigated to guide our policy and technology choices. A large variety of stationary battery technologies exists, however previous studies have failed to assess the environmental implications of several of them. In this study, the environmental performance of Lithium Metal Polymer (LMP) stationary batteries is quantified through the life cycle assessment methodology and compared to Lithium-ion (Li-ion) units. LMP is a promising technology which is advocated as more stable, safe and simple to manufacture than batteries with liquid electrolytes. Models with a storage capacity of 6 MWh and 75 kWh are examined, corresponding respectively to batteries designed for a centralized and a distributed grid configuration. The assessments cover the entire life cycle of the batteries and evaluate their impacts in fifteen different environmental categories. The results show that the battery manufacturing stage drives the majority of environmental impacts in the different investigated batteries. Li-ion batteries cause significantly more impacts than LMP units in terms of global warming and ozone depletion. The effects on global warming come mainly from the production of components in countries where fossil fuel dominates electricity mixes. The production of polytetrafluoroethylene, used only in Li-ion batteries, is the main contributor to the ozone layer depletion category and also an important source of global warming emissions. Conversely, LMP batteries are responsible for a bigger impact in terms of aquatic eutrophication originating from sulfidic tailings linked to mining activities. An additional finding of this study is that centralized battery system configurations bring smaller environmental impacts than distributed systems with more but smaller storage units.

Roles of Dynamic State Estimation in Power System Modeling, Monitoring and Operation

Abstract: Power system dynamic state estimation (DSE) remains an active research area. This is driven by the absence of accurate models, the increasing availability of fast-sampled, time-synchronized measurements, and the advances in the capability, scalability, and affordability of computing and communications. This paper discusses the advantages of DSE as compared to static state estimation, and the implementation differences between the two, including the measurement configuration, modeling framework and support software features. The important roles of DSE are discussed from modeling, monitoring and operation aspects for today's synchronous machine dominated systems and the future power electronics-interfaced generation systems. Several examples are presented to demonstrate the benefits of DSE on enhancing the operational robustness and resilience of 21st century power system through time critical applications. Future research directions are identified and discussed, paving the way for developing the next generation of energy management systems and novel system monitoring, control and protection tools to achieve better reliability and resiliency.