1. Definition of micro hydropower
Micro-hydropower is a system that converts the potential energy of small streams and rivers (i.e. micro-hydropower resources) into electrical energy facilities and equipment that meet the requirements of residential electricity. Its working principle is basically the same as small hydropower, but the installed capacity is smaller. At present, the installed capacity of micro-hydroelectricity in different countries around the world, the general pattern is that the industrialized countries tend to be large. The maximum installed capacity of micro-hydro power in the United Kingdom is l000 kilowatts, followed by the maximum installed capacity of 500 kilowatts in the United States and France, and the maximum installed capacity of 100 kilowatts in China’s current standards for micro-hydro power.
Micro-hydro power system mainly consists of water storage and diversion building, micro-hydro power station and power supply system.
The water storage and diversion building includes dam, water intake, diversion channel, etc.; micro-hydro power station includes machine room, micro-hydro generator set, power distribution device, pressure front pool, sewage interception facilities, water diversion pipeline, unit tail water discharge channel, etc.; the power supply system mainly consists of substation equipment, transmission lines, line safety protection device. The core of which is the micro-hydro generator set, which is mainly composed of three major components: hydraulic turbine, generator and controller (or speed governor).
It can be seen that micro-hydropower is a set of water, hydraulic, mechanical, electrical, control, transmission, civil engineering and other technologies as one of the system engineering, not only technically complex, difficult working conditions, and engineering quality and operating procedures involving personal safety.
2. Classification
(1) single-family micro-hydropower technology. Single-family micro hydropower equipment of small power, generally are the whole unit. Single-family micro hydropower is only for single-family users, the required investment capital, engineering volume is also very small, can be self-invested by farmers, self-built, self-management, self-use. The construction of single-family micro-hydro power station includes civil construction, equipment installation and power transmission. Single-family micro hydropower configuration of the generator is generally permanent magnet generator, which has the advantages of simple structure, reliable operation, high efficiency, less maintenance or maintenance-free, easy to use, etc.. Single-family micro-hydropower station needs to be equipped with an electronic regulator for automatic voltage and frequency stabilization, and the distance of power supply should not exceed 1 km.
The power generation capacity of single-family units is divided into: 100, 200, 300, 500, 800 watts, 1, 2, 5 kW, etc.
The water flow required for single-family type hydropower station is 40-140 cubic meters / hour, with a drop of 2-40 meters. Generally on small streams and rivers to choose the natural formation of higher drop for construction.
(2) village-level networked micro-hydropower technology. Village level network type micro hydropower its equipment to the whole installation unit, power generation can be used for a natural village (10 ~ 100 households), construction and installation should be carried out under the guidance of professional and technical personnel. The unit is equipped with automatic voltage and frequency stabilization electronic regulator or governor, multiple units can be networked for power supply, easy to operate and use. Power supply range in principle should be within 2 km, should not exceed 5 km at most.
Village level networked micro-hydropower equipment generation capacity of 5 to 30 kilowatts. The water flow required for the power station is 100 to 500 cubic meters / hour, with a drop of 5 to 60 meters. It needs to build or borrow hydraulic structures to meet its water resources requirements.
(3) Township-level grid-connected micro-hydropower technology. Grid-connected micro-hydropower at the village level has an installed capacity of 30-100 kilowatts and uses grid-connected power supply, which can supplement the power supply at the end of the grid in the mountain and countryside and improve the quality of power supply and operational efficiency of the mountain and countryside grid. The power generation equipment is mainly the whole installed units, which need to be installed with grid-connected substation equipment. The construction of the power station should be formally surveyed and designed, and the project should be carried out under the management and guidance of professional technicians.
Grid-connected micro-hydro power station to sell electricity to the grid, and then by the grid to the user power supply, to overcome the micro-hydro independent power supply dry period five electricity available, issued by the electricity can not be fully utilized, the power generation households themselves charge high labor costs and can not avoid disputes and other off-grid operation of the three inherent obstacles, can gradually become one of the mountain farmers to become rich low-risk investment projects.
Township-level grid-connected micro-hydropower stations require water resources with a flow rate of 100 to 10,000 cubic meters / hour and a drop of 5 to 120 meters. Often need to borrow small one or two type of reservoirs or larger irrigation canals storage and transfer of water, in order to ensure the annual power generation time, to achieve better economic benefits.
3. Application effectiveness
(1) Economic benefits. The direct economic benefit of micro-hydro power comes from the income from the sale of electricity. At present, there are three ways to supply and sell micro-hydro power: First, self-generation, saving their own electricity expenses. Second, direct power supply to customers, power generation households door-to-door charges to users. The third is to sell electricity to the power company on a grid-connected basis. There are many factors affecting the income from electricity sales, and the general situation of the current working micro-hydro power station is that the average annual electricity sales revenue per kilowatt-hour is 1,000 yuan. Many power generation households have their own processing workshops such as rice milling and flour milling, which can increase their income by 2 to 5 times compared to direct electricity sales. Therefore, power generation households are often the first to become rich in the local family. At present, in mountainous rural areas, if the sale of electricity is guaranteed by government regulations, micro-hydro power at the village and township levels will become a popular project for local farmers to invest in.
(2) Social benefits. Micro-hydropower resources mainly exist in mountainous areas with abundant precipitation, and are only suitable for local development and utilization due to small investment and low output. From the development of micro hydropower, the current status of property rights, the use of the effect can be seen, micro hydropower is born in farmers (the main body of investment is the local farmers), built in rural areas, for agricultural (maintenance of farmland water conservancy, the realization of agricultural and by-products of electric plus / 12) “three agricultural” hydropower. Its social attributes are definitely “agricultural”. The development and utilization of micro-hydro power is in the mountainous areas where the economic development is relatively backward, and its direct social benefit is to help the disadvantaged groups, improve the living and production conditions of local farmers, and help farmers to get rid of poverty and become rich. A 300-watt micro-hydro electric rice mill can save farmers the trouble of walking dozens of miles up the mountain to grind rice. A 5-kilowatt micro-hydroelectric unit supporting the installation of the grinder, annual savings of five to six thousand dollars in electricity costs for farmers specializing in the production of roti. Coffee farmers in Yunnan use micro-hydropower to drag the coffee hulling machine, solving the problem of difficult hulling after coffee harvest. Farmers in Xiling Snow Mountain, Dayi, Sichuan, use micro hydropower to set up tourist reception stations in the scenic mountains, so that visitors can enjoy the beautiful scenery during the day and carry out activities such as karaoke, dancing and watching videos at night. At present, micro-hydro power stations are gradually emerging in mountainous rural areas, using the income from the sale of electricity to maintain farmland water conservancy facilities, “electricity for irrigation” action, for the maintenance of some small reservoirs opened up a promising new ideas, but also become a new direction of micro-hydro power development.
4. China’s technology research and development status
After more than 20 years of efforts, China’s micro hydropower technology has made great progress in hydraulic turbine, generator and controller. At present, the efficiency of most domestic micro-hydropower complete units is between 40% and 60%, and the service life is 10-15 years. A batch of integrated complete units, after several years of operation, have proved that their service life, stability and ease of installation and operation have reached the requirements of productization and are suitable for China’s rural areas. 2006 has also seen the success of multi-unit parallel power supply in Sichuan micro-hydropower. In general, as long as the user can afford it financially, it can fully meet its requirements technically. Since the resource situation of micro-hydropower varies greatly, it is often not easy for users to find micro-hydropower equipment products that fully meet their requirements. If users put forward their own requirements, they must bear the additional costs, which is a consistent practice in the hydropower industry, and used in micro-hydro, it will be unaffordable for micro-hydro investors, greatly hindering the development of micro-hydro. Therefore, it is necessary to develop a series of micro-hydropower equipment that can cover micro-hydropower resources as a basis for the large-scale promotion of micro-hydropower technology.
5. Foreign development
(1) Development status. Foreign developed countries, such as the United States, the United Kingdom, Canada, etc., rely on their good industrial base to produce micro-hydro power in terms of reliability and generator and turbine efficiency compared with domestic micro-hydro power has a greater advantage. The efficiency of foreign micro-hydropower machines can reach up to 75%, and their service life can reach 20 years. As the demand for micro-hydro power in developing countries grows and the awareness of environmental protection increases, micro-hydro power is beginning to receive attention from governments. Some larger companies and research institutes abroad have started to pay attention to the research and development of micro-hydropower, but they have not yet done anything big.
(2) Development trend. The production of hydropower equipment is a single-piece production, manufacturing costs are very high, it is bound to become a workshop production. All the world’s micro hydropower equipment, including micro hydropower units in the United Kingdom, Canada, the United States and other developed countries, are also from home factories. In order to improve product quality and reduce production costs, often in similar professional products to find alternative components, such as water and electricity pumps instead of hydraulic turbines, diesel generators instead of hydroelectric generators, etc., and achieved good results. Especially in the small power unit, the unit integrated with alternative parts has the potential to replace the special unit.
(3) The inspiration for China. As China has a good working basis for small hydropower development, UNIDO has high expectations for China in the world of micro hydropower development. Many countries also continue to seek cooperation in micro-hydropower in China, but they are still in the small-scale experimental stage. China should set up a project to carry out research and development of series micro-hydro power equipment as soon as possible, and cover the whole micro-hydro energy resources with 3 to 5 series of products to form mass production, so as to establish the cost-performance advantage of China’s micro-hydro power equipment in the international arena.
微水电概述
1．微水电的定义
微型水力发电简称微水电，是指将小溪、小河水(即微水能资源)的位能转换成符合民用电要求的电能设施和设备组成的系统。其工作原理和小水电基本相同，但装机容量较小。目前，世界各国对微水电的装机容量规定不一，总的格局是工业发达的国家趋于大。英国规定微水电的最大装机容量为l000千瓦，其次是美国和法国规定微水电的最大装机容量为500千瓦，我国现行标准规定微水电的最大装机容量为100千瓦。
微水电系统主要由蓄水引水建筑、微水电站和供电系统三部分组成。
蓄水引水建筑包括水坝、取水口、引水渠等；微水电站包括机房、微型水力发电机组、配电装置、压力前池、拦污排污设施、引水管道、机组尾水排放渠道等；供电系统主要由变电设备、输电线路、线路安全保护装置构成。其中核心的是微型水力发电机组，它主要由水轮机、发电机、控制器(或调速器)三大部件组成。
由此可见，微水电是集水利、水工、机械、电机、控制、输电、土建等多项技术为一体的系统工程，不仅技术复杂、工作条件艰苦，而且工程质量和操作规程涉及人身安全。
2．分类
(1)单户型微水电技术。单户型微水电设备的功率小，一般都是整装机组。单户型微水电只供单家独户的用户使用，所需要的投入资金、工程量等也很小，可以由农户自投、自建、自管、自用。单户型微水电站建设包括土建、设备安装和电力输送等内容。单户型微水电配置的发电机一般为永磁发电机，它具有结构简单、运行可靠、效率高、少维护或免维护、使用方便等优点。单户型微水电站需要配备自动稳压和稳频的电子调控器，供电距离不应超过1千米。
单户型机组的发电量分为：100、200、300、500、800瓦，1、2、5千瓦等。
单户型水电站所需要的水流量为40—140立方米／时，落差为2—40米。一般在小溪小河上选择自然形成的较高落差进行建造。
(2)村级联网型微水电技术。村级联网型微水电其设备以整装机组为主，发电可以供一个自然村(10～100户)使用，建设安装应在专业技术人员的指导下进行。机组配有自动稳压和稳频的电子调控器或调速器，可多台机组联网供电，操作使用方便。供电范围原则上应在2千米之内，最多不应超过5千米。
村级联网型微水电设备发电量为5～30千瓦。电站需要的水资源流量为100～500立方米／时，落差5～60米。需要建造或借用水工建筑才能满足其水资源要求。
(3)乡级并网型微水电技术。乡级并网型微水电的装机容量为30—100千瓦，采用并网供电，可以对处于电网末端山乡电网进行电力就近补充，提高山乡电网的供电质量和运行效率。发电设备以整装机组为主，需要安装并网变电设备。电站建设应进行正规勘测和设计，工程要在专业技术人员的管理指导下进行。
并网型微水电站向电网卖电，再由电网向用户供电，克服了微水电独立供电枯水期五电可供，发出的电无法全部利用，发电户自己收费的高人力成本及无法避免纠纷等离网运行三大固有障碍，可以逐步成为山区农民致富的低风险投资项目之一。
乡级并网型微水电站需要的水资源流量为100～10000立方米／时，落差5～120米。往往需要借用小一或小二型水库或较大的灌溉水渠蓄调水量，才能保证年发电时间，取得较好的经济效益。
3．应用成效
(1)经济效益。微水电的直接经济效益来源于卖电收入。目前微水电的供电和卖电方式有三种：一是自发自用，节省自家电费开支。二是直接向用户供电，发电户上门向用电户收费。三是并网向供电公司卖电。影响卖电收入的因数很多，目前正常工作的微水电站的普遍情况是平均每千瓦时每年的卖电收人为1000元。不少发电户都自己办有碾米磨面等加工作坊，可使收入比直接卖电提高2～5倍。因此，发电户往往都会成为当地先行致富的人家。目前，在山区农村，如果卖电方面得到政府的法规保障，村级、乡级的微水电就会成为当地农民投资的热门项目。
(2)社会效益。微水电资源主要存在于降水量丰富的山区，由于投资小、产出少，只适合于在当地开发利用。从微水电的开发情况、产权现状、利用效果都可以看出，微水电是生于农民(投资主体是当地农民)、建于农村、利于农业(养护农田水利、实现农副产品的电动加／12)的“三农”水电。其社会属性肯定姓“农”。微水电的开发利用是在经济发展相对落后的山区，其直接的社会效益就是扶助弱势群体，改善当地农民的生活生产条件，帮助农民脱贫致富。一台300瓦的微水电电动碾米机，可使农民省去担着稻谷走几十里山路去碾米的烦恼。一台5千瓦的微水电机组配套安装磨浆机后，每年为腐竹生产专业农户节省电费五六千元。云南的咖农用微水电拖动咖啡脱壳机，解决了咖啡收获后脱壳难的问题。四川大邑西岭雪山的农民利用微水电在风景秀丽的山上办起了旅游接待站，使游客们白天能欣赏美丽的风光，夜晚又能开展卡拉OK、跳舞、看录像等活动。目前山区农村正在逐步兴起的办微水电站，用卖电收入养护农田水利设施的“以电养灌”行动，为部分小型水库的养护开辟出一条充满希望的新思路，也成为微水电发展的一个新方向。
4．我国技术研发现状
经过20多年的努力，我国微水电技术在水轮机、发电机、控制器等方面都取得了长足的进步。目前，国内微水电的整机效率大多在40％～60％之间，使用寿命为10～15年。一批一体化的整装机组，经过几年的运行，证明其使用寿命、稳定性、安装操作方便性等都达到了产品化的要求，适用于我国农村。2006年，在四川微水电的多机并联供电也取得了成功。总的来说，只要用户在经费上能够承受，在技术上完全可以满足其要求。由于微水电的资源情况差异很大，用户往往不容易找到完全符合自己要求的微水电设备产品。如果用户提出自己的要求，就必须承担额外的费用，这是水电行业的一贯做法，而用在微水电上，就会让微水电投资者难以承受，极大地阻碍了微水电的发展。因此，必需开发出能够覆盖微水电资源的系列化微水电设备，以此作为微水电技术规模化推广的基础。
5．国外发展情况
(1)发展现状。国外发达国家，如美国、英国、加拿大等，依靠其良好的工业基础，生产的微水电在可靠性和发电机、水轮机效率两个方面与国内微水电相比有较大的优势。国外微水电的整机效率最高可达到75％，使用寿命可达20年。随着发展中国家微水电需求量的增长和各国环保意识的增强，微水电开始受到各国政府的重视。国外的一些较大公司和研究所开始关注微水电的研发工作，但是尚没有大的作为。
(2)发展趋势。水电设备的生产属于单件生产，制造成本很高，必然成为作坊式的生产。世界上所有的微水电设备，包括英国、加拿大、美国等发达国家的微水电机组，也都是出自家庭工厂。为了提高产品质量、降低生产成本，经常在相近专业产品中去寻找替代部件，如用水电泵替代水轮机，以柴油发电机替代水力发电机等，取得了很好的效果。尤其是小功率机组方面，替代部件集成的机组大有取代专用机组之势。
(3)对我国的启示。由于中国小水电开发有很好的工作基础，联合国工发组织在世界微水电发展方面对中国寄予厚望。许多国家也不断在中国寻求微水电方面的合作，但目前都还处于小规模试验阶段。我国应该尽快立项开展系列化微水电设备的研发，以3～5个系列的产品覆盖整个微水能资源，形成批量生产，以确立我国微水电设备在国际上的性价比优势。
1．微水电的定义
微型水力发电简称微水电，是指将小溪、小河水(即微水能资源)的位能转换成符合民用电要求的电能设施和设备组成的系统。其工作原理和小水电基本相同，但装机容量较小。目前，世界各国对微水电的装机容量规定不一，总的格局是工业发达的国家趋于大。英国规定微水电的最大装机容量为l000千瓦，其次是美国和法国规定微水电的最大装机容量为500千瓦，我国现行标准规定微水电的最大装机容量为100千瓦。
微水电系统主要由蓄水引水建筑、微水电站和供电系统三部分组成。
蓄水引水建筑包括水坝、取水口、引水渠等；微水电站包括机房、微型水力发电机组、配电装置、压力前池、拦污排污设施、引水管道、机组尾水排放渠道等；供电系统主要由变电设备、输电线路、线路安全保护装置构成。其中核心的是微型水力发电机组，它主要由水轮机、发电机、控制器(或调速器)三大部件组成。
由此可见，微水电是集水利、水工、机械、电机、控制、输电、土建等多项技术为一体的系统工程，不仅技术复杂、工作条件艰苦，而且工程质量和操作规程涉及人身安全。
2．分类
(1)单户型微水电技术。单户型微水电设备的功率小，一般都是整装机组。单户型微水电只供单家独户的用户使用，所需要的投入资金、工程量等也很小，可以由农户自投、自建、自管、自用。单户型微水电站建设包括土建、设备安装和电力输送等内容。单户型微水电配置的发电机一般为永磁发电机，它具有结构简单、运行可靠、效率高、少维护或免维护、使用方便等优点。单户型微水电站需要配备自动稳压和稳频的电子调控器，供电距离不应超过1千米。
单户型机组的发电量分为：100、200、300、500、800瓦，1、2、5千瓦等。
单户型水电站所需要的水流量为40—140立方米／时，落差为2—40米。一般在小溪小河上选择自然形成的较高落差进行建造。
(2)村级联网型微水电技术。村级联网型微水电其设备以整装机组为主，发电可以供一个自然村(10～100户)使用，建设安装应在专业技术人员的指导下进行。机组配有自动稳压和稳频的电子调控器或调速器，可多台机组联网供电，操作使用方便。供电范围原则上应在2千米之内，最多不应超过5千米。
村级联网型微水电设备发电量为5～30千瓦。电站需要的水资源流量为100～500立方米／时，落差5～60米。需要建造或借用水工建筑才能满足其水资源要求。
(3)乡级并网型微水电技术。乡级并网型微水电的装机容量为30—100千瓦，采用并网供电，可以对处于电网末端山乡电网进行电力就近补充，提高山乡电网的供电质量和运行效率。发电设备以整装机组为主，需要安装并网变电设备。电站建设应进行正规勘测和设计，工程要在专业技术人员的管理指导下进行。
并网型微水电站向电网卖电，再由电网向用户供电，克服了微水电独立供电枯水期五电可供，发出的电无法全部利用，发电户自己收费的高人力成本及无法避免纠纷等离网运行三大固有障碍，可以逐步成为山区农民致富的低风险投资项目之一。
乡级并网型微水电站需要的水资源流量为100～10000立方米／时，落差5～120米。往往需要借用小一或小二型水库或较大的灌溉水渠蓄调水量，才能保证年发电时间，取得较好的经济效益。
3．应用成效
(1)经济效益。微水电的直接经济效益来源于卖电收入。目前微水电的供电和卖电方式有三种：一是自发自用，节省自家电费开支。二是直接向用户供电，发电户上门向用电户收费。三是并网向供电公司卖电。影响卖电收入的因数很多，目前正常工作的微水电站的普遍情况是平均每千瓦时每年的卖电收人为1000元。不少发电户都自己办有碾米磨面等加工作坊，可使收入比直接卖电提高2～5倍。因此，发电户往往都会成为当地先行致富的人家。目前，在山区农村，如果卖电方面得到政府的法规保障，村级、乡级的微水电就会成为当地农民投资的热门项目。
(2)社会效益。微水电资源主要存在于降水量丰富的山区，由于投资小、产出少，只适合于在当地开发利用。从微水电的开发情况、产权现状、利用效果都可以看出，微水电是生于农民(投资主体是当地农民)、建于农村、利于农业(养护农田水利、实现农副产品的电动加／12)的“三农”水电。其社会属性肯定姓“农”。微水电的开发利用是在经济发展相对落后的山区，其直接的社会效益就是扶助弱势群体，改善当地农民的生活生产条件，帮助农民脱贫致富。一台300瓦的微水电电动碾米机，可使农民省去担着稻谷走几十里山路去碾米的烦恼。一台5千瓦的微水电机组配套安装磨浆机后，每年为腐竹生产专业农户节省电费五六千元。云南的咖农用微水电拖动咖啡脱壳机，解决了咖啡收获后脱壳难的问题。四川大邑西岭雪山的农民利用微水电在风景秀丽的山上办起了旅游接待站，使游客们白天能欣赏美丽的风光，夜晚又能开展卡拉OK、跳舞、看录像等活动。目前山区农村正在逐步兴起的办微水电站，用卖电收入养护农田水利设施的“以电养灌”行动，为部分小型水库的养护开辟出一条充满希望的新思路，也成为微水电发展的一个新方向。
4．我国技术研发现状
经过20多年的努力，我国微水电技术在水轮机、发电机、控制器等方面都取得了长足的进步。目前，国内微水电的整机效率大多在40％～60％之间，使用寿命为10～15年。一批一体化的整装机组，经过几年的运行，证明其使用寿命、稳定性、安装操作方便性等都达到了产品化的要求，适用于我国农村。2006年，在四川微水电的多机并联供电也取得了成功。总的来说，只要用户在经费上能够承受，在技术上完全可以满足其要求。由于微水电的资源情况差异很大，用户往往不容易找到完全符合自己要求的微水电设备产品。如果用户提出自己的要求，就必须承担额外的费用，这是水电行业的一贯做法，而用在微水电上，就会让微水电投资者难以承受，极大地阻碍了微水电的发展。因此，必需开发出能够覆盖微水电资源的系列化微水电设备，以此作为微水电技术规模化推广的基础。
5．国外发展情况
(1)发展现状。国外发达国家，如美国、英国、加拿大等，依靠其良好的工业基础，生产的微水电在可靠性和发电机、水轮机效率两个方面与国内微水电相比有较大的优势。国外微水电的整机效率最高可达到75％，使用寿命可达20年。随着发展中国家微水电需求量的增长和各国环保意识的增强，微水电开始受到各国政府的重视。国外的一些较大公司和研究所开始关注微水电的研发工作，但是尚没有大的作为。
(2)发展趋势。水电设备的生产属于单件生产，制造成本很高，必然成为作坊式的生产。世界上所有的微水电设备，包括英国、加拿大、美国等发达国家的微水电机组，也都是出自家庭工厂。为了提高产品质量、降低生产成本，经常在相近专业产品中去寻找替代部件，如用水电泵替代水轮机，以柴油发电机替代水力发电机等，取得了很好的效果。尤其是小功率机组方面，替代部件集成的机组大有取代专用机组之势。
(3)对我国的启示。由于中国小水电开发有很好的工作基础，联合国工发组织在世界微水电发展方面对中国寄予厚望。许多国家也不断在中国寻求微水电方面的合作，但目前都还处于小规模试验阶段。我国应该尽快立项开展系列化微水电设备的研发，以3～5个系列的产品覆盖整个微水能资源，形成批量生产，以确立我国微水电设备在国际上的性价比优势。