1. Small Hydro Power Plants

Compact Hydro stands for “water to wire” solutions based on pre-designed modular components and offers a single source of supply for the entire electromechanical equipment, as well as workshop-tested units, reduced dimensions for transportation and short installation times. For Mini Compact Hydro the level of standardization and parametrization was deeper expanded, keeping the same level of performances and quality, for lower investment costs and simplifying operation and maintenance of small hydropower plants. Francis units The features of the Francis turbines ensure a wide application field according to specific needs. Guarantees of efficiency, output and resistance to cavitation for single and double discharge runners are based on model tests from the ANDRITZ HYDRO laboratories. Francis turbines propose the highest efficiency.

As far as the standard concept is applicable, the runner is directly fitted on the generator shaft, which ensures a compact construction and low maintenance. For smaller units the turbine-generator aggregate is delivered as a complete assembly package ready for immediate installation.

Mini hydro from 20 to 3,000 kW and heads from 10 to 150 m. Small hydro from about 500 kW up to 30 MW and heads up to 300 m. Horizontal or vertical axis. Single or double discharge runners.

Spiral intake or open flume Pelton units up to 30 MW Guarantees of efficiency and output are based on model tests from the ANDRITZ HYDRO laboratories for one to three nozzles in horizontal and three to six nozzles in vertical arrangement. The flow control of the Pelton turbine, via operation of nozzles and deflectors, provides a high efficiency along the flow range of operation as well as limited overpressure effect over the penstock. Over the years, the Compact Hydro Division has also developed a strong expertise in special applications for hydraulic turbines, like the energy recovery in Reverse Osmosis desalination process or in the drinking and waste water systems.

Mini hydro from 100 to 5,000 kW and heads from 60 to 800 m. Small hydro up to 30 MW and heads from 50 to 1,000 m. Horizontal, 1 to 3 nozzles. Vertical, 1 to 6 nozzles. Generators. Synchronous or asynchronous type. Horizontal or vertical shaft.

Air or water cooled. Brushless excitation Electrical equipment Electrical equipment includes solutions for unit control, protection systems, and cabling and power transmission To meet the requirements of the market in conjunction with the Compact Hydro turbines, an overall concept has been implemented which comprises both the mechanical and electrical equipment of the powerhouse. Following the modular concept of the mechanical equipment, we also implement the same approach with the balance of plant:. Generators with AVR. Control-protection-measuring system. Digital turbine governor. Supervisory Control and Data Acquisition (SCADA).

AC-DC distribution. Auxiliary transformer. LV and MV-switchgear. Transformer. Substation. Transmission line This means that the Compact Hydro division is in a position to tender both the hydro-mechanical equipment, as well as the total or partial electrical equipment up to a unit output of 30 MW.

Small hydropower stations are usually run off schemes. The most known example in central Europe would probably be a traditional mill. In most countries where water power is used mills have been the firs usage. Originally the water wheel drove the millstones directly. Modern use Turbines instead of water wheels and mostly power a generator to produce electricity. But in cases where machinery can be used and installed near the turbine direct driven systems have some advantages. Such systems are purely mechanical and therefore extremely robust.

Actually there is no comprehensive technology to drive machinery without combustion engines. Categories on small hydropower are mostly taken by size of output power. Nevertheless is the upper limit of a locations power determined by the local conditions like amount of flowing water and height difference. Table 1: Classification of small hydropower by size kW (Kilowatt) = 1000 Watts; MW (Megawatt) = 1,000,000 Watts or 1000 kW.

Figure 1: Layout of a typical micro hydro scheme There are various other configurations which can be used depending on the topographical and hydrological conditions, but all adopt the same general principle. Water into Watts To determine the power potential of the water flowing in a river or stream it is necessary to determine both the flow rate of the water and the head through which the water can be made to fall. The flow rate is the quantity of water flowing past a point in a given time. Typical flow rate units are litres per second or cubic meters per second.

The head is the vertical height, in meters, from the turbine up to the point where the water enters the intake pipe or penstock. The potential power can be calculated as: P = g.

Q. H. f eff Example: A location with a head of 10 metres, flow of 300 liter / sec (= 0.3 m 3/s) will have a potential power of 15 kW electricity: 10m/s 2.

0.3m 3/s. 10m.

0.5 = 15m 5 /s 3 = 15m 5/s 3. 1000 kg/m 3 (density of water) = 15000 J/s = 15000 W = 15kW Power in kW (P); Flow rate in m 3 /s (Q); Head in m (H); Gravity constant = 9.81 m/s 2 (g); Efficiency factor (f eff) = 0.4 - 0.7.Small water turbines rarely have efficiency better than 80%. Generators' efficiency of 90% and power will also be lost in the pipe carrying the water to the turbine, due to frictional losses. A rough guide used for small systems of a few kW rating is to take the overall efficiency as approximately 50%.

Thus, the theoretical power must be multiplied by 0.50 for a more realistic figure If a machine is operated under conditions other than full-load or full-flow then other significant inefficiencies must be considered. Part flow and part load characteristics of the equipment needs to be known to assess the performance under these conditions. It is always preferable to run all equipment at the rated design flow and load conditions, but it is not always practical or possible where river flow fluctuates throughout the year or where daily load patterns vary considerably. Depending on the end use requirements of the generated power, the output from the turbine shaft can be used directly as mechanical power or the turbine can be connected to an electrical generator to produce electricity. For many rural industrial applications shaft power is suitable (for food processing such as milling or oil extraction, sawmill, carpentry workshop, small scale mining equipment, etc.), but many applications require conversion to electrical power.

For domestic applications electricity is preferred. This can be provided either:.

directly to the home via a small electrical distribution system or,. can be supplied by means of batteries which are returned periodically to the power house for recharging - this system is common where the cost of direct electrification is prohibitive due to scattered housing (and hence an expensive distribution system), Where a generator is used alternating current (a.c.) electricity is normally produced.

Singlephase power is satisfactory on small installations up to 20kW, but beyond this, 3-phase power is used to reduce transmission losses and to be suitable for larger electric motors. Power supply must be maintained at a constant 50 or 60 cycles/second for the reliable operation of any electrical equipment using the supply. This frequency is determined by the speed of the turbine which must be very accurately governed. Suitable Conditions for Micro-Hydro Power The best geographical areas for exploiting small-scale hydro power are those where there are steep rivers flowing all year round, for example, the hill areas of countries with high year-round rainfall, or the great mountain ranges and their foothills, like the Andes and the Himalayas. Islands with moist marine climates, such as the Caribbean Islands, the Philippines and Indonesia are also suitable. Low-head turbines have been developed for small-scale exploitation of rivers where there is a small head but sufficient flow to provide adequate power. To assess the suitability of a potential site, the hydrology of the site needs to be known and a site survey carried out, to determine actual flow and head data.

Hydrological information can be obtained from the meteorology or irrigation department usually run by the national government. This data gives a good overall picture of annual rain patterns and likely fluctuations in precipitation and, therefore, flow patterns. The site survey gives more detailed information of the site conditions to allow power calculation to be done and design work to begin. Flow data should be gathered over a period of at least one full year where possible, so as to ascertain the fluctuation in river flow over the various seasons. There are many methods for carrying out flow and head measurements and these can be found in the relevant texts.

Turbines A turbine converts the energy in falling water into shaft power. There are various types of turbine which can be categorised in one of several ways. The choice of turbine will depend mainly on the pressure head available and the design flow for the proposed hydropower installation. As shown in table 2 below, turbines are broadly divided into three groups; high, medium and low head, and into two categories: impulse and reaction. Table 2: Classification of turbine types. Head pressure Turbine Runner High Medium Low Impulse.

Pelton. Turgo. Multi-jet Pelton. Crossflow. Turgo. Multi-jet Pelton.

Crossflow Reaction. Francis. Pump-as-turbine (PAT). Propeller. Kaplan.

The difference between impulse and reaction can be explained simply by stating that the impulse turbines convert the kinetic energy of a jet of water in air into movement by striking turbine buckets or blades - there is no pressure reduction as the water pressure is atmospheric on both sides of the impeller. The blades of a reaction turbine, on the other hand, are totally immersed in the flow of water, and the angular as well as linear momentum of the water is converted into shaft power - the pressure of water leaving the runner is reduced to atmospheric or lower. Load Factor The load factor is the amount of power used divided by the amount of power that is available if the turbine were to be used continuously. Unlike technologies relying on costly fuel sources, the 'fuel' for hydropower generation is free and therefore the plant becomes more cost effective if run for a high percentage of the time. If the turbine is only used for domestic lighting in the evenings then the plant factor will be very low. If the turbine provides power for rural industry during the day, meets domestic demand during the evening, and maybe pumps water for irrigation in the evening, then the plant factor will be high.

It is very important to ensure a high plant factor if the scheme is to be cost effective and this should be taken into account during the planning stage. Many schemes use a 'dump' load (in conjunction with an electronic load controller - see below), which is effectively a low priority energy demand that can accept surplus energy when an excess is produced e.g.

Water heating, storage heaters or storage cookers. Load control governors Water turbines, like petrol or diesel engines, will vary in speed as load is applied or relieved. Although not such a great problem with machinery which uses direct shaft power, this speed variation will seriously affect both frequency and voltage output from a generator. Traditionally, complex hydraulic or mechanical speed governors altered flow as the load varied, but more recently an electronic load controller (ELC) has been developed which has increased the simplicity and reliability of modern micro-hydro sets. The ELC prevents speed variations by continuously adding or subtracting an artificial load, so that in effect, the turbine is working permanently under full load. A further benefit is that the ELC has no moving parts, is very reliable and virtually maintenance free. The advent of electronic load control has allowed the introduction of simple and efficient, multi-jet turbines, no longer burdened by expensive hydraulic governors.

Other Issues. The Economics - Cost Reduction Normally, small-scale hydro installations in rural areas of developing countries can offer considerable financial benefits to the communities served, particularly where careful planning identifies income-generating uses for the power.

The major cost of a scheme is for site preparation and the capital cost of equipment. In general, unit cost decreases with a larger plant and with high heads of water. It could be argued that small-scale hydro technology does not bring with it the advantages of 'economy of scale', but many costs normally associated with larger hydro schemes have been 'designed out' or 'planned out' of micro hydro systems to bring the unit cost in line with bigger schemes. In recent years there has been much debate over the appropriate scale of hydro power.

Many argue that large hydro is not only environmentally damaging (as large areas of land are flooded) but that there is also a negative social impact where large imported technologies are used. Summary The information below provides a short summary for constructing a small hydro power.

Equip a Certain Place with Hydropower (A) 1. Check the sites feasibility.

This means, gather the following Data: head, flow, number of consumers, location data (distance from grid.). ► Go there and fill out this form = ► If you need further quick information go to 2. Calculate the sites hydropower potential: Multiply the (minimal) flow in liter/second with the available height difference.

The result times 5 gives you an estimation on how many Watts can be produced. ► see also 3.

Estimate the required power at the site. Separate consumer power and productive use power. Keep in mind that transmission cables are costly. Consumers basics are light and TV.

Light requires min. 5 -20 Watt per bulb (5 W = energy saving lamp, if available). A TV requires 40 - 150 W (depending on size and type). Machinery needs much more power. Palfinger pk 12000 specs. Motors may require from 1000 Watt (1kW = small) upward. Heating needs also a lot power (min.

500 W for a small water heater). Compare the local hydropower potential with the de'mand of electric power. If the potential is to be gained, check if the Data from point 1. Is really valid. Is the measured flow available all year round? Is the head available on a short horizontal distance - means 'how long have and to be?' Cost estimation: There is no general cost estimation possible as any site differs from the other.

Biggest cost blocks are usually: Civil structure: Ask a company to find out the local cost for building (material). Mansion cost per m 3 weir - 1.5 m height x width of river; cost per m canal - size depends on water volume; cost per m 2 powerhouse 10 - 25 m 2 Penstock: ask the local prices for pipes - size depends on water volume Turbine, Generator, Controller: Ask a turbine manufacturer for an offer for your power range and site conditions (flow and head). The final price will range between the offer from a German producer and some Chinese products. Transmission line: Check required local standards. Ask the cable cost/meter for your potential power. Cable length goes from powerhouse towards the load center (village center) Transformer: Power 10 kW and long transmission lines 2 km require transformer stations. House connections: Depending on distance towards house and power line (cable length), number of appliances (just lights?), safety standards (mcb) and metering devices/ load limiters.

please feel free to extend and sharpen this cost section see A) 3. Integrate the potentially affected communities as soon as possible in the process. If supplying a local or isolated grid the local community plays a key role for the sites later success. Do not ever promise anything before you sure that a project will be implemented at a certain location. Concentrate on cooperation and integration of participants.

Use local resources where ever possible. Social issues are usually much more complicated than technical issues. They are time consuming, may vary during the process and are different on each location. Nevertheless a working social network is usually the biggest factor towards success.

Micro-hydro Design Manual, A Harvey & A Brown, ITDG Publishing, 1992. Micro-hydro power: A guide for development workers, P Fraenkel, O Paish, V Bokalders, A Harvey & A Brown, ITDG Publishing, IT Power, Stockholm Environment Institute, 1991. Small hydro Power in China, ITDG Publishing, 1985.

Motors as Generators for Micro-Hydro Power, Nigel Smith, IT Publications, 1994. Pumps as Turbines - A users guide, Arthur Williams, ITDG Publishing, 1995. Rural Energy in Peru - Power for Living, ITDG, 1996. Low-cost Electrification - Affordable Electricity Installation for Low-Income Households in Developing Countries, IT Consultants/ODA, 1995.

Small Hydro Power Plants

The Micro-hydro Pelton Turbine Manual: Design, Manufacture and Installation for Small-scale Hydropower, Jeremy Thake, ITDG Publishing, 2000.Going with the Flow: Small-scale Water Power, Dan Curtis, CAT 1999. The Role of the Private Sector in the Small-scale Hydropower Field, K. Goldsmith, SKAT, 1995.