Abstract:Wind power generation reduces our reliance on fossil fuels and can thus reduce environmental pollution. However, rapid wind power development has caused various issues related to power grid restructuring. A high proportion of the generating capacity of northeast China is based on combined heat and power (CHP), whose inflexible response to the peak regulation of power grids hinders the ability to accommodate wind power; thus, wind power curtailment is prevalent. Electric boilers can directly consume the excess wind power to supply heat during low load periods and thus mitigate the heat supply stress of CHP units. Therefore, electric boilers improve the power grid's ability to accommodate additional wind power. From a regional power grid perspective, this paper discussed the feasibility of such a strategy for increasing the ability to accommodate wind power during the heat supply season. This paper analysed the optimum electric boiler capacity configuration of a regional power grid based on various constraint conditions, such as the heat-power balance, with the objective of maximising the associated social benefits. Using the Beijing-Tianjin-Hebei power grid as an example, the optimum electric boiler capacity of the studied power grid is approximately 1100 MW.

The experiment of improving Selective Non-Catalytic Reduction (SNCR) denitrification efficiency with gas additives (CH4 and C3H8) was carried out in the 50 kW circulating fluidized bed (CFB) pilot-scale equipment. The results show that the denitrification efficiency can reach 20 % when the reaction temperature is 650 °C, and the optimum mole ratio of C3H8/NH3 is 0.5. The denitrification efficiency can exceed 50 % when the mole ratio of C3H8/NH3 is 0.4 and the reaction temperature is 720 °C. However, the CH4 additive does not promote denitrification at this temperature. When the reaction temperature is 760 °C, the optimum denitrification efficiency of CH4 is 60 %, and the required CH4/NH3 is 0.8. Once the amount of CH4 exceeds the optimal value, the denitrification efficiency is suppressed. In addition, the concentrations of N2O and CO in the gas increase significantly with an increase of gas additives. Due to the incomplete oxidation of C3H8, a large amount of C2H4 is produced in the low-temperature region (< 750 °C) of SNCR.

So far, compressed air energy storage (CAES) system is another effective technology for large-scale energy storage which can improve grid flexibility and realize the grid generation of renewable energy. This paper reviews the developments of CAES technology including operation principles, application fields, technology performance of different types of CAES system and the current state-of-art. Finally, the potential key application prospects of CAES in future are discussed.

Natural gas-fired cogeneration power plant is the key joint which connects the natural gas pipeline network, power grid and district heat supply network. Thus its supply and consumption capacity of heat-power-gas is pivotal to the co ordination of urban energy system. Based on material and energy balance principle, the process model of a natural gas-fired combined cycle cogeneration power plant is established. By conducting off-design simulations, a set of boundary capacity data is obtained which enclose the capacity area of heat and power supply under given natural gas consumption. The heat power-gas capacity area can provide essential information on the natural gas-fired cogeneration power plants for urban energy co ordination system.

This study presents application of demand response strategy in a standalone wind-solar-battery hybrid energy system (HES). Inputs for the designed HES are wind speed, solar radiation, temperature and load demand which is variable with time. In this study, hourly values of meteorological data and hourly load demand are considered in one year. An improved gravitational search algorithm (IGSA) is used to optimize the configuration of the standalone wind-solar-battery hybrid power system. The optimal objectives of the system are cost of the system in life cycle, the loss of power supply probability（LPSP）and the energy excess percentage（EXC）.The effect of demand response on economic benefit and energy storage allocation of the standalone wind-solar-battery system is studied. The obtained optimal configuration of the proposed HES can provide minimal energy cost with excellent performance and reduced waste and unmet load.