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With many favorable advantages including fast response ability in particular, utility-level energy storage systems (ESS) are being integrated into energy and reserve markets to help mitigate uncertain renewable resources and fluctuant demands. This paper discusses a stochastic unit commitment (UC) model to explore capabilities of ESSs in providing valuable grid services by simultaneously joining energy and reserve markets. The proposed reserve model of ESSs presents the following features: (i) two constraints are proposed to formulate ESS’s reserve provision ability in each hour via six operation modes, namely increasing/reducing the level of charge, switching to discharge, increasing/reducing the level of discharge, switching to charge; (ii) as an energy-limited asset, constraints on ESS’s reserve deliverability across multiple hours is introduced to hold enough state of charge (SOC) headroom and floor room, guaranteeing that reserves cleared in individual hours are continuously deliverable over multiple successive hours without violating operation limits. Moreover, a scenario-based UC model, which addresses uncertainties of renewables and demands, is adopted to evaluate reserves provided by ESSs and generators. To effectively solve the stochastic UC problem, the progressive hedging algorithm with heuristic approaches is discussed. A 6-bus system and a modified IEEE 118-bus system are used to illustrate effectiveness of the proposed approaches.

With many favorable advantages including fast response ability in particular, utility-level energy storage systems (ESS) are being integrated into energy and reserve markets to help mitigate uncertain renewable resources and fluctuant demands. This paper discusses a stochastic unit commitment (UC) model to explore capabilities of ESSs in providing valuable grid services by simultaneously joining energy and reserve markets. The proposed reserve model of ESSs presents the following features: (i) two constraints are proposed to formulate ESS’s reserve provision ability in each hour via six operation modes, namely increasing/reducing the level of charge, switching to discharge, increasing/reducing the level of discharge, switching to charge; (ii) as an energy-limited asset, constraints on ESS’s reserve deliverability across multiple hours is introduced to hold enough state of charge (SOC) headroom and floor room, guaranteeing that reserves cleared in individual hours are continuously deliverable over multiple successive hours without violating operation limits. Moreover, a scenario-based UC model, which addresses uncertainties of renewables and demands, is adopted to evaluate reserves provided by ESSs and generators. To effectively solve the stochastic UC problem, the progressive hedging algorithm with heuristic approaches is discussed. A 6-bus system and a modified IEEE 118-bus system are used to illustrate effectiveness of the proposed approaches.

The enzymatic hydrolysis of the native and the pretreated palm pressed fiber (PPF) was deeply investigated by using the enzyme cocktail ACCELLERASE 1500. Together with the spent PPF from the first hydrolysis and the further doubly-treated PPF, the proportions of three main components were determined and analyzed based on a triangle figure. The proportion (cellulose/hemicelluloses/lignin) in the spent PPF was equal to 44:23:33 and the surface morphology of the spent PPF looks very similar to the native PPF surface showing poor hydrolysis efficiency. After further double treatment, the proportion was changed evidently from the original 44:23:33 to 54:21:25 and the surface structure was significantly disrupted showing a potential to be hydrolyzed completely. Additionally, all samples were characterized by Fourier transform infrared spectroscopy and X-ray diffractogram through considerations of alkaline solution treatment, so as to understand better the nature of biomass hydrolysis, from the aspect of three biomass components.

The enzymatic hydrolysis of the native and the pretreated palm pressed fiber (PPF) was deeply investigated by using the enzyme cocktail ACCELLERASE 1500. Together with the spent PPF from the first hydrolysis and the further doubly-treated PPF, the proportions of three main components were determined and analyzed based on a triangle figure. The proportion (cellulose/hemicelluloses/lignin) in the spent PPF was equal to 44:23:33 and the surface morphology of the spent PPF looks very similar to the native PPF surface showing poor hydrolysis efficiency. After further double treatment, the proportion was changed evidently from the original 44:23:33 to 54:21:25 and the surface structure was significantly disrupted showing a potential to be hydrolyzed completely. Additionally, all samples were characterized by Fourier transform infrared spectroscopy and X-ray diffractogram through considerations of alkaline solution treatment, so as to understand better the nature of biomass hydrolysis, from the aspect of three biomass components.

It is found via the analysis of the meteorological data in Chengdu that the number of annual average calm wind days is more than 240. In the non-calm wind time, the dominant wind direction is not obvious, while the annual average wind speed is about 1.0 m/s. In consequence, problems arise as to indoor ventilation in residential buildings without mechanical ventilation in this climate zone and the way how local residential wind has adapted and improved natural ventilation for a long time. In this paper, the state of indoor ventilation in this zone is studied by measuring the concentration of carbon dioxide in the house for a long time. And the long-term adaptive improvement strategy of local residents to the ventilation of residential buildings in calm climate zone is investigated. So are strategies and experiences of local residents in improving natural ventilation in residential buildings.

It is found via the analysis of the meteorological data in Chengdu that the number of annual average calm wind days is more than 240. In the non-calm wind time, the dominant wind direction is not obvious, while the annual average wind speed is about 1.0 m/s. In consequence, problems arise as to indoor ventilation in residential buildings without mechanical ventilation in this climate zone and the way how local residential wind has adapted and improved natural ventilation for a long time. In this paper, the state of indoor ventilation in this zone is studied by measuring the concentration of carbon dioxide in the house for a long time. And the long-term adaptive improvement strategy of local residents to the ventilation of residential buildings in calm climate zone is investigated. So are strategies and experiences of local residents in improving natural ventilation in residential buildings.

The sodium storage mechanism of hard carbon, optimization strategies of electrochemical performance, and the scientific challenges towards the commercialization of sodium-ion batteries were systematically summarized and analyzed.