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By establishing a two-stage model in which a monopolization firm first chooses R&D input and then the quantity of energy, this paper compares the different effects of two regulatory policies: feed-in tariff (FIT) and renewable portfolio standard (PRS). The results show that FIT is more efficient than RPS to increase the quantity of renewable energy (installed capacity) and to stimulate the R&D input to reduce costs. And RPS policy is more efficient to reduce the carbon emissions and to improve the consumer surplus. Apart from existing findings, we cannot obtain the accurate conclusion about the effects of social welfare under the two policies. The effects of two policies on the social welfare heavily depend on the level of negative externality.

Abstract A novel solar concentrating PV and thermal (CPVT) combined system with beam splitter and compact concentrator structure is proposed in this study. The system structure and its design method are provided. The optical filter is designed and the incident light angle effect on the beam splitting performance is investigated. Solar concentrating simulations are conducted and the relevant results reveal that the CPVT combined system can provide a high solar concentration uniformity. The evaluation results of configuration and optical analyses indicate that when all the other parameters are settled, the optimal installation height of the solar receiver tube is 923.0 mm. The influence study of sun tracking accuracy on the system optical performance is launched. It is concluded that when the tracking error increases to 1.0°, the overall optical efficiency is 66.2%. The thermodynamic analysis results indicate that the PV conversion and overall energy efficiencies of the CPVT system are 30.5% and 26.6%, which are both higher than those of the normal CPV system. Moreover, the operating temperature effect investigation of solar thermal receiver tube is conducted. The results show that an optimal solar thermal receiver tube temperature (356.0 °C) exists, which can result in the maximum total output power.

Abstract Large volumes of polymeric waste, including natural biomass residues and synthetic waste, motivate the development of a general, robust and flexible process for mining the energy and resources contained in these wastes. By analyzing the positive and negative aspects of current, conventional technologies for the recovery of energy from polymeric waste, an integrated concept of a hybrid technology combining biochemical (anaerobic digestion, gas fermentation, carbon chain elongation) and thermochemical conversion processes (pyrolysis, gasification, hydrothermal carbonization) was proposed. The hybrid technology aims at simultaneously enhancing the efficiency and stability of biochemical conversion, controlling the gaseous and aqueous pollution from thermochemical conversion, and sequestering carbon. This paper presents a detailed review of state-of-the-art research relating to the principles, technical feasibility and practices involved in each technical link between the two conversion processes.

Understanding and simulating the dynamic characteristics of the hydro-turbine governor system is essential to guarantee the safety of the hydro-power systems. This study proposes a modification method of the water head at the draft tube inlet, which is to discretize the draft tube and introduce the excitation term of the vortex rope. The proposed approach is applied for the modeling of the hydro-turbine governor system. The proposed model (Model I) is verified by means of a comparison with a second model (Model II) of the hydro-turbine governor system model without considering the vortex rope and verified against the experimental data during the load reduction. The model developed is accurate providing errors of the water head, inlet water head and flow of the hydro-turbine for Model ¿ are within ±3.3%, ±2% and ±5%, respectively. The proposed model overcomes the limitations of Model ¿ in the time-domain and frequency-domain since that only provides the average pressure at the draft tube, which do not reflect the pressure fluctuation and energy fluctuation. Instead the proposed model allows to capture and model the energy fluctuation during the load reduction as shown in the experimental results. The proposed model promotes the development of the hydro-turbine governor system model. Peer Reviewed