Study on Environment Friendly Urban Energy System

这项研究旨在评估各种关键措施，以实现更良性的城市能源系统。它们是：1)热电联产，2)光伏发电和3)热级联发电。这些措施的研究结果总结如下：1.在促进热电联产渗透到城市能源市场的各种措施中，零售转盘非常有希望，因为它提供了灵活的需求作为缓冲。热电厂的热电比是影响电厂利用率的关键参数。2.位于房顶的光伏发电的优点是配电成本低，但缺点主要来自其输出功率的多变性。对光伏发电的经济分析表明，光伏发电一半以上的价值来自传统发电厂的可替代性，而不是能源成本的降低。根据我们的分析，光伏的盈亏平衡成本比目前的成本低一个数量级，这表明要降低光伏成本，还需要付出更多的努力。并对光伏发电对电力系统LFC容量的影响进行了评估。3.能源梯级是提高社会能效的有效措施之一。能源密集型行业内部的级联将节省总一次能源的几个百分点，但与住宅和商业部门一起级联更有效，因为工业的低温余热可用于向这些部门提供供暖和热水。

This study aims at assessing various key measures for more benign urban energy systems. They are :1) cogeneration, , 2) photovoltaics and 3) heat cascading. The results of the study on these measures are summarized as follows.1.Among various measures which facilitate penetration of cogeneration into the urban energy market retail sales wheeling is very promising in the sense that it provides with flexible demand as buffer. Heat/electricity ratio of the cogeneration plant is a key parameter affecting the usefulness of the plant.2.While the advantage of photovoltaics located on the roofs of houses is the low cost in power distribution, its disadvantage comes mainly from changeability of its outputs. The economic analysis of PV indicates that more than a half of its value comes from its substitutability of conventional power plants, rather than from reduction in energy cost. According to our analysis PV's breakeven cost is of 1 order lower than it pressent cost ; it indicates that much efforts are indispensable for reduction in PV costs. Impacts of PV on LFC capacity of the power system are also evaluated in this study.3.Energy cascading is one of the effective measures for improving energy efficiency in a society. Cascading within energy intensive industries will save a few per cent of the total primary energy, but cascading together with residential and commercial sectors is more effective in the sense that low temperature waste heat from industries may be utilized in heat and hot water supply to these sectors.