Regarded as a long-term, large capacity energy storage solution, commercialized power-to-gas(PtG) technology has attracted much research attention in recent years.PtG plants and natural gas-fired power plants can form a close loop between an electric power system and a natural gas network. An interconnected multi-energy system is believed to be a solution to the future efficient and environmental friendly energy systems. However, some crucial issues require in-depth analysis before PtG plants can be economically implemented. This paper discusses current development status and potential application of PtG plants in the future interconnected multi-energy systems, and further analyzes the costs and benefits of PtG plants in different application scenarios. In general, the PtG plants are not economical efficient based on current technologies and costs. But the situation is likely to change with the development of PtG technologies and interconnected operation of gas-electricity energy system.
With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30% of the maximum load in many cities during summer.This paper proposes a scheme of constructing a virtual peaking unit(VPU) by public buildings’ cool storage central AC(CSCAC) systems and non-CSCAC(NCSCAC)systems for the day-ahead power network dispatching(DAPND). Considering the accumulation effect of different meteorological parameters, a short term load forecasting method of public building’s central AC(CAC) baseline load is firstly discussed. Then, a second-order equivalent thermal parameters model is established for the public building’s CAC load. Moreover, the novel load reduction control strategies for the public building’s CSCAC system and the public building’s NCSCAC system are respectively presented. Furthermore, based on the multiple-rank control strategy, the model of the DAPND with the participation of a VPU is set up. The VPU is composed of large-scale regulated public building’s CAC loads. To demonstrate the effectiveness of the proposed strategy, results of a sample study on a region in Nanjing which involves 22 public buildings’ CAC loads are described in this paper. Simulated results show that, by adopting the proposed DAPND scheme, the power network peak load in the region obviously decreases with a small enough deviation between the regulated load value and the dispatching instruction of the VPU. The total electricity-saving amount accounts for7.78% of total electricity consumption of the VPU before regulation.
大容量风力发电基地的快速发展给电力系统安全与经济运行带来了新的问题,对输电系统进行规划时,既要考虑具备足够的可用输电能力(available transfer capability,ATC)以容纳大规模风电并网,又要避免输电容量过分冗余造成投资浪费。在此背景下,针对含有大容量风力发电的电力系统,提出了一种计及ATC的输电系统规划随机优化模型,主要内容包括:(1)在考虑风速和负荷等随机变量之间相关性以及线路和发电机故障概率的基础上,构造了ATC概率模型;(2)采用拉丁超立方采样和灵敏度分析相结合的方法求解ATC概率模型;(3)构建以输电线路投资成本最小和ATC期望值最大为目标的优化模型,将输电系统规划的经济性和运行风险进行有机结合。采用遗传算法求解所建立的输电系统规划优化模型,并用18节点和46节点算例系统说明所发展模型和方法的基本特征。
