Small hydroelectric station with your own hands. DIY hydro generator or homemade hydroelectric power station

IN Lately, due to rising electricity tariffs, renewable sources of virtually free energy are becoming increasingly relevant.

Small hydroelectric power station or small hydroelectric power station (SHPP) - a hydroelectric power station that generates a relatively small amount of electricity and is based on hydropower plants with a capacity of 1 to 3000 kW. There is no concept of a small hydroelectric power station generally accepted for all countries; their installed capacity is taken as the main characteristic of such hydroelectric power stations.

Installations for small hydropower are classified by power into:

equipment for mini hydroelectric power stations with a capacity of up to 100 kW;
equipment for micro hydroelectric power plants with a power of up to 1000 kW.

From the well-known classical triad: solar panels, wind generators, hydroelectric generators (hydroelectric power plants), the latter the most complex. Firstly, they work in aggressive conditions, and secondly, they have the maximum operating time in an equal period of time.

It is easiest to make damless hydroelectric power stations, because The construction of a dam is quite complex and expensive and often requires coordination with local authorities or at least with neighbors. Damless mini hydroelectric power stations are called flow-through ones. There are four main options for such devices.

Types of mini hydroelectric power stations

Water wheel is a wheel with blades mounted perpendicular to the surface of the water. The wheel is less than half immersed in the flow. Water presses on the blades and rotates the wheel. There are also turbine wheels with special blades optimized for liquid flow. But these are quite complex designs, more factory-made than home-made.

Garland mini-hydroelectric power station- is a cable with rotors rigidly attached to it. The cable is thrown from one bank of the river to the other. The rotors are strung like beads on a cable and are completely immersed in water. The flow of water rotates the rotors, the rotors rotate the cable. One end of the cable is connected to the bearing, the other to the generator shaft.

Rotor Daria is a vertical rotor that rotates due to the pressure difference on its blades. The pressure difference is created due to the flow of liquid around complex surfaces. The effect is similar to the lift of a hydrofoil or the lift of an airplane wing.

Propeller is an underwater “windmill” with a vertical rotor. Unlike an air propeller, an underwater propeller has blades of minimal width. For water, a blade width of only 2 cm is sufficient. With such a width, there will be minimal resistance and maximum rotation speed. This width of the blades was chosen for a flow speed of 0.8-2 meters per second. At higher speeds, other sizes may be optimal.

Advantages and disadvantages of various mini-hydroelectric power plant systems

Flaws garland SHPP obvious: high material consumption, danger to others (long underwater cable, rotors hidden in the water, blocking the river), low efficiency. Garlyandnaya hydroelectric power station is a small dam. Rotor Daria Difficult to manufacture, it needs to be untwisted at the beginning of work. But it is attractive because the rotor axis is located vertically and power can be taken off over water, without additional gears. Such a rotor will rotate with any change in flow direction.

Thus, from the point of view of ease of manufacture and obtaining maximum efficiency with minimal cost, it is necessary to choose a design like water wheel or propeller.

Design of a small hydraulic power station

Design of a small hydroelectric power station is based on a hydraulic unit, which includes a power unit, a water intake device and control elements. Depending on what hydro resources are used by small hydropower plants, they are divided into several categories:

Channel or dam stations with small reservoirs;

Stationary mini hydroelectric power stations using the energy of the free flow of rivers;

SHPPs that use existing differences in water levels at various water management facilities;

Mobile mini hydroelectric power plants in containers, used as pressure diversion plastic pipes or flexible reinforced hoses.

Types of hydraulic units for small hydroelectric power plants

The basis for a small hydraulic station is a hydraulic unit, which, in turn, is based on a turbine of one type or another. There are hydraulic units with:

Axial turbines;

Radial-axial turbines;

Bucket turbines;

Rotary blade turbines.

SHPPs are also classified depending on the maximum use of water pressure per:

High-pressure - more than 60 m;

Medium pressure - from 25 m;

Low pressure - from 3 to 25 m.

The types of turbines used in the equipment also differ depending on the water pressure used by the microhydroelectric power plant. Bucket and radial-axial turbines are designed for high-pressure hydroelectric power plants. Rotary-blade and radial-axial turbines are used at medium-pressure stations. At low-pressure small hydroelectric power stations (SHPPs), rotary-blade turbines are mainly installed in reinforced concrete chambers.

As for the operating principle of a mini hydroelectric power station turbine, it is almost identical in all designs: water under pressure flows onto the turbine blades, which begin to rotate. The rotational energy is transferred to a hydrogenerator, which is responsible for generating electricity. Turbines for objects are selected in accordance with certain technical characteristics, among which the main one is water pressure. In addition, turbines are selected depending on the type of chamber that comes with the kit - steel or reinforced concrete.

The power of mini-hydroelectric power plants depends on the pressure and flow of water, as well as on the efficiency of the turbines and generators used. Due to the fact that, according to natural laws, the water level is constantly changing, depending on the season, as well as for a number of other reasons, it is customary to take cyclic power as an expression of the power of a hydroelectric station. For example, there are annual, monthly, weekly or daily work cycles.

When choosing a mini hydroelectric power station, you should focus on power equipment that would be adapted to the specific needs of the facility and meet criteria such as:

Availability of reliable and easy-to-use control and monitoring equipment;

Equipment control in automatic mode with the ability to switch to manual control if necessary;

The generator and turbine of the hydraulic unit must have reliable protection from probable emergency situations;

Areas and volumes construction work for the installation of small hydroelectric power stations should be minimal.

Benefits of using mini hydroelectric power stations:

Low-power hydroelectric power plants have a number of advantages that make this equipment increasingly popular. First of all, it is worth noting environmental safety mini hydro power plants are a criterion that is becoming increasingly important in light of protection issues environment. Small hydroelectric power plants do not have a harmful effect on either the properties or the quality of water. The water areas where a low-power hydroelectric power station is installed can be used both for fishing activities and as a source of water supply settlements. In addition, for the operation of small hydroelectric power stations there is no need for large reservoirs. They can function using the energy of the flow of small rivers and even streams.

Concerning economic efficiency, then here too micro and mini hydroelectric power plants have many advantages. Stations designed with modern technologies, are easy to operate and are fully automated. Thus, the equipment does not require human presence. Experts note that the quality of the current generated by small hydroelectric power plants meets GOST requirements for both voltage and frequency. At the same time, mini hydroelectric power stations can operate both autonomously and as part of the power grid.

Speaking about small hydroelectric power plants, it is worth noting their advantage, such as their full service life, which is at least 40 years. Well, and most importantly, small-scale energy facilities do not require the organization of large reservoirs with corresponding flooding of the territory and colossal material damage.

One of the most important economic factors is the eternal renewability of hydraulic resources. If we calculate the literal benefits from the use of small hydroelectric power plants, it turns out that the electricity generated by them is almost 4 times cheaper than the electricity that the consumer receives from thermal power plants. It is for this reason that today hydroelectric power plants are increasingly being used to supply power to electrically intensive industries.

Let's not forget that small hydroelectric power plants do not require the purchase of any fuel. In addition, they are distinguished by a relatively simple technology for generating electricity, as a result of which labor costs per unit of power at hydroelectric power plants are almost 10 times less than at thermal power plants.

Mini-hydroelectric power station - Leneva's dam-free hydropower unit - with a river flow speed of 1 m/s, a mini-hydroelectric power station installation with dimensions of 1.5 * 0.7 * 0.6 m produces 11 kW.

Mini-hydroelectric power station - Leneva hydropower unit:

Mini-hydroelectric power station - hydropower unit Leneva N.I. uses original, not previously used in any of the existing structures, a method of obtaining energy both from water flow of any kind (rivers, streams, tides, sea waves, etc.) and from movement air masses. In this case, the natural flow is used, without preliminary transformation (construction of dams, canals, pressure pipes).

This method of extracting the power of the water flow is the most beneficial from an environmental point of view, since it does not at all disturb the natural bed of the river, occupying from 1% to 10% of the area, thereby not interfering with the free movement of river fauna and flora, unlike existing hydroelectric power stations .

At a river flow speed of 1 m/s hydropower unit Leneva N.I. dimensions 1.5*0.7*0.6 m produces 11 kW.

Design of the Leneva hydropower unit:

Mini-hydroelectric power station - Leneva hydropower unit is a system (two rows) of blades rectangular shape(flat plate) whose axes divide them into two (1/2) unequal parts, the larger of which is always (due to the action of the flow) located behind the axis further down the flow. This ensures minimal rotation around its axis and, consequently, minimal turbulent turbulence.

The axes of the blades, with their upper and lower parts, in turn, are fixed on the upper and lower, closed in rings - PRL chains (or on any other flexible element). The chains transmit force through sprockets (impellers) to two vertical shafts, from which the mechanical energy of the moving medium (water, air, etc., etc.) through a flexible coupling and intermediate shaft is transmitted to the shafts electric generators. The installation shafts through sliding (rolling) bearings are rigidly fixed to the frame of the hydraulic power unit, which has 2/3 closed side walls and a blank bottom wall, which does not prevent the flow of additional water from the surrounding flow through the top and 1/3 of the side walls of the hydraulic power unit.

It is rational to place at least three in one frame block installations of mini-hydroelectric power stations.

The position of the blades in relation to the main flow is regulated by fixed guides for the chain and movable ones for the larger side of the blade, and by changing the distance between the movable guide for the blade and the fixed one for the chain, we set required angle rotation between the blade and the direction of the main flow from 0 0 to 45 0, thereby achieving the optimal operating mode of the hydraulic power unit or stopping it completely. Thus, the flow acts on the blade virtually perpendicularly, at 90 0. One of the shafts of the hydropower unit has stretching device regulating chain tension. The blades must have freedom of rotation on their axes, and the axes must also rotate freely when attached to the chains. Between the blade and the place of attachment to the chain, rollers must be installed on the axles, which will roll along fixed guides, thereby keeping the chain constantly in a perpendicular position relative to the direction of the main flow.

The sizes of mini-hydroelectric power stations are not limited. Determined by the required power and size of the river. As an example, let’s take: width – 1200 mm, depth – 700 mm, length – 1250 mm, i.e. volume – 1 m3. It allows you to place 3 installations with 17 blades in each, which, in turn, have a width of 150 mm and a depth of 500 mm, i.e. each area is 0.075 m2. Since two blades will always be on the turns, then the total working area of one hydropower unit installation is 1.125 m2, the sum of 3 mini-hydroelectric power plant installations in one frame (1 m3 of flow) will be 3.375 m2!!!

The shaft rotation speed is only 30-60 rpm.

It is this design of the hydropower unit that allows for the fullest use of each cubic meter flow of a moving medium, resulting centrifugal and centripetal accelerations, significantly increasing both the speed of the flow and the effect of gravity of the flow of a moving medium, in our case a river, divided into sections.

The material consumption of one kilowatt of mini-hydroelectric power station, depending on the materials used for production, will vary from several hundred grams (plastic, ultra high molecular weight polyethylene) up to 2-3 kg (steel) per 1 kW of installed power.

Description of the operating principle of mini-hydroelectric power stations:

Hydropower unit Leneva N.I. creates in front of it a small backwater of 10 centimeters at a flow speed of 1 m/sec, and behind it - a vacuum, and therefore the water falling from this backlash affects the blade at a different speed than in the surrounding flow. If there is also a vacuum at the outlet of the mini-hydroelectric power plant, the flow increases its speed under the influence of centrifugal force and the gravitational constant! This is not difficult to see in the photographs presented by the outgoing flow and the breakers it creates. The hydraulic power unit works like a pump.

Advantages of the Leneva hydropower unit:

– increased working area of the hydropower unit. In the installation of a mini-hydroelectric power station there is not a single blade that would not work at any given moment or would interfere with the work of the others. The blades are arranged in two rows, each of which is a working one. When turning, the blades also work,

– the form of installation creates a modular design of the hydropower unit, which makes it possible to build larger ones hydroelectric power stations from miniblocks for small, medium and large consumers,

– the working blades of the hydraulic power unit are located in relation to the moving flow under optimal angle at 45 degrees. Thus, the mini-hydroelectric power station not only does not stop the movement of water, taking away all its energy, but also provokes the emergence of additional forces that significantly increase the power of the water flow, and, accordingly, our own

Since electricity tariffs have recently begun to rise, renewable sources of electricity are becoming increasingly important among the population, allowing them to receive electricity almost free of charge. Among known to mankind Such sources include solar panels, wind generators, and home hydroelectric power stations. But the latter are quite complex, because they have to work in very aggressive conditions. Although this does not mean that it is impossible to build a mini-hydroelectric power station with your own hands.

To do everything correctly and efficiently, the main thing is to choose the right materials. They must ensure maximum durability of the station. Do-it-yourself home hydro generators, the power of which is comparable to that of solar panels and wind turbines can produce much more energy. But although a lot depends on the materials, everything does not end there.

Types of mini hydroelectric power plants

Exists a large number of various variations of mini-hydroelectric power stations, each of which has its own advantages, features and disadvantages. Highlight the following types these devices:

garland;
propeller;
Daria rotor;
water wheel with blades.

A garland hydroelectric power station consists of a cable on which rotors are attached. Such a cable is pulled across the river and immersed in water. The flow of water in the river begins to rotate the rotors, which in turn rotate the cable, at one end of which there is a bearing, and at the other - a generator.

The next type is a water wheel with blades. It is installed perpendicular to the water surface, submerging less than half. As the flow of water acts on the wheel, it rotates and causes the generator for the mini-hydroelectric power station on which this wheel is attached to rotate.

Classic water wheel - a well forgotten old one

As for the propeller hydroelectric power station, it is a wind turbine located under water with a vertical rotor. The width does not exceed 2 centimeters. This width is enough for water, because this is the nominal value that allows you to produce maximum amount electricity with minimal resistance. True, this width is optimal only for flow speeds up to 2 meters per second.

As for other conditions, the parameters of the rotor blades are calculated separately. And the Darrieus rotor is a vertically positioned rotor that operates on the principle of differential pressure. Everything happens similarly with an airplane wing, which is affected by lift.

Advantages and disadvantages

If we consider a garland hydroelectric power station, then it has a number of obvious shortcomings. Firstly, the long cable used in the design poses a danger to others. Rotors hidden under water also pose a great danger. Well, in addition, it is worth noting the low efficiency indicators and high material consumption.

As for the disadvantages of the Darrieus rotor, in order for the device to start generating electricity, it must first be spun up. True, in this case, power is taken directly above the water, so no matter how the water flow changes, the generator will generate electricity.

All of the above are factors that make hydraulic turbines for mini-hydroelectric power plants and water wheels more popular. If we consider a manual construction similar devices, then they are not that complicated. And in addition, when minimum costs such mini-hydroelectric power plants are capable of producing maximum efficiency indicators. So the criteria for popularity are obvious.

Where to start construction

The construction of a mini-hydroelectric power station with your own hands should begin with measuring the speed indicators of river flows. This is done very simply: just mark a distance of 10 meters upstream, pick up a stopwatch, throw a chip into the water, and note the time it takes for it to cover the measured distance.

Ultimately, if you divide 10 meters by the number of seconds taken, you get the speed of the river in meters per second. It is worth considering that there is no point in building mini-hydroelectric power stations in places where the flow speed does not exceed 1 m/s.

If the reservoir is far away, you can build a bypass channel

If you need to figure out how mini-hydroelectric power stations are made in areas where the river speed is low, then you can try to increase the flow by organizing a height difference. This can be done through installation drain pipe into the pond. In this case, the diameter of the pipe will directly affect the speed of water flow. The smaller the diameter, the faster the flow.

This approach makes it possible to organize a mini-hydroelectric power station even if there is a small stream passing near the house. That is, a collapsible dam is organized on it, below which a mini-hydroelectric power station is installed directly to power the house and household appliances.

Regular increases in electricity prices make many people think about the issue of alternative sources of electricity. One of best solutions V in this case- hydroelectric power station. The search for a solution to this issue concerns not only the scale of the country. More and more often you can see mini-hydroelectric power plants for the home (dacha). The costs in this case will only be for construction and Maintenance. The disadvantage of such a structure is that its construction is possible only under certain conditions. A water flow is required. In addition, the construction of this structure in your yard requires permission from local authorities.

Mini-hydroelectric power station diagram

Channel, characteristic of plains. They are installed on rivers with low flows.
Stationary ones use the energy of water rivers with fast flow of water.
Hydroelectric power stations installed in places where the water flow drops. They are most often found in industrial organizations.
Mobile, which are built using reinforced hoses.

For the construction of a hydroelectric power station, even a small stream flowing through the site is sufficient. Home owners with central water supply should not despair.

One of American companies A station has been developed that can be built into the water supply system of a home. A small turbine is built into the water supply system, which is driven by the flow of water moving by gravity. This reduces the flow rate of water, but reduces the cost of electricity. In addition, this installation is completely safe.

Even mini-hydroelectric power stations are being built in sewer pipe. But their construction requires the creation certain conditions. Water through the pipe should flow naturally due to the slope. The second requirement is that the pipe diameter must be suitable for the installation of the equipment. And this cannot be done in a separate house.

Classification of mini-hydroelectric power plants

Mini-hydroelectric power plants (the houses in which they are used are mostly in the private sector) most often belong to one of following types, which differ in their operating principle:

The water wheel is the traditional type, which is the easiest to implement.
Propeller. They are used in cases where the river has a bed more than ten meters wide.
The garland is installed on rivers with a gentle flow. To increase the speed of water flow, additional structures are used.
The Darrieus rotor is usually installed in industrial enterprises.

The prevalence of these options is due to the fact that they do not require the construction of a dam.

Water wheel

This classic look Hydroelectric power station, which is most popular for the private sector. Mini hydro power plants of this type They are a large wheel that can rotate. Its blades descend into the water. The rest of the structure is above the riverbed, causing the entire mechanism to move. The power is transmitted through a hydraulic drive to a generator that produces current.

Propeller station

On the frame in a vertical position there is a rotor and an underwater windmill, lowered under water. A windmill has blades that rotate under the influence of water flow. The best resistance is provided by blades two centimeters wide (with a fast flow, the speed of which, however, does not exceed two meters per second).

In this case, the blades are driven by the resulting water pressure rather than by it. Moreover, the direction of movement of the blades is perpendicular to the direction of flow. This process is similar to wind power plants, only it works underwater.

Garlyandnaya hydroelectric power station

This type of mini-hydroelectric power station consists of a cable stretched over a river bed and secured in a support bearing. Turbines of small size and weight (hydraulic rotors) are hung and rigidly fixed on it in the form of a garland. They consist of two half-cylinders. Due to the alignment of the axes when lowered into the water, a torque is created in them. This causes the cable to bend, stretch and begin to rotate. In this situation, the cable can be compared to a shaft that serves to transmit power. One of the ends of the cable is connected to the gearbox. The power from the rotation of the cable and hydraulic propellers is transmitted to it.

The presence of several “garlands” will help increase the power of the station. They can be connected to each other. Even this does not greatly increase the efficiency of this hydroelectric power station. This is one of the disadvantages of such a structure.

Another disadvantage of this species is the danger it creates for others. This kind of station can only be used in deserted places. Warning signs are required.

Rotor Daria

A mini-hydroelectric power station for a private house of this type is named after its developer, Georges Darrieus. Patented this design was back in 1931. It is a rotor on which the blades are located. The required parameters are selected individually for each blade. The rotor is lowered under water in a vertical position. The blades rotate due to the pressure difference resulting from water flowing over their surface. This process is similar to the lift that makes airplanes take off.

This type of hydroelectric power station has good indicator Efficiency Threefold advantage - the direction of flow does not matter.

Among the disadvantages of this we can highlight complex design and difficult installation.

Advantages of mini-hydroelectric power stations

Regardless of the type of design, mini-hydroelectric power plants have a number of advantages:

They are environmentally friendly and do not produce substances harmful to the atmosphere.
The process of generating electricity takes place without creating noise.
The water remains clean.
Electricity is generated constantly, regardless of the time of day or weather conditions.
Even a small stream is enough to set up a station.
Excess electricity can be sold to neighbors.
You don't need a lot of permitting documentation.

Do-it-yourself mini hydroelectric power station

You can build it yourself to generate electricity. For a private home, twenty kilowatts per day is enough. Even a mini-hydroelectric power station assembled with your own hands can cope with this value. But it should be remembered that this process is characterized by a number of features:

It is quite difficult to make accurate calculations.
The dimensions and thickness of the elements are selected “by eye”, only experimentally.
Self-made structures do not have protective elements, which leads to frequent breakdowns and associated costs.

Therefore, if you do not have experience and certain knowledge in this area, it is better to abandon this kind of idea. It may be cheaper to purchase a ready-made station.

If you still decide to do everything yourself, then you need to start by measuring the speed of water flow in the river. After all, the power that can be obtained depends on this. If the speed is less than one meter per second, then the construction of a mini-hydroelectric power station in this location will not be justified.

Another stage that cannot be omitted is calculations. It is necessary to carefully calculate the amount of costs that will go into building the station. As a result, it may turn out that the hydroelectric power plant is not the best option. Then you should pay attention to other types of alternative electricity.

Mini-hydroelectric power station can become optimal solution in terms of saving energy costs. For its construction, there must be a river near the house. Depending on the desired characteristics, you can select suitable option Hydroelectric power station. At the right approach You can even make a similar construction with your own hands.

Hydroelectric power plants use the power of water to generate electrical energy. Self-made stations solve the problem of distance from centralized power grids or help save on electricity.

Advantages and disadvantages of hydroelectric power stations

Hydroelectric power plants have the following advantages over other types of alternative energy sources:

They do not depend on the weather and time of day (unlike). This allows more energy to be produced at a predictable rate.
The power of the source (river or stream) can be adjusted. To do this, it is enough to narrow the channel with a dam or provide a difference in water heights.
Hydraulic installations do not make any noise (unlike).
Many types of low power stations do not require any installation permits.

The disadvantages of homemade hydroelectric power plants include the inability to work in cold weather. In addition, the aquatic environment is aggressive, so the station parts must be waterproof and durable.

When designing mini-hydroelectric power plants for use as an alternative energy source for own home The following factors should be decisive:

Proximity of the river to the house. Install homemade station It's not worth it far from home. The further away the installation, the lower its efficiency, because some of the energy will be lost during transmission. In addition, it is more difficult to protect your hydroelectric power station from theft or damage.
Sufficient flow speed or the possibility of increasing it. The power of the station increases by geometric progression with increasing water speed.

It's easy to find out the speed. Throw a piece of foam or a tennis ball into the water and time the time it takes for it to swim a certain distance. Then divide the meters by seconds and you will know the speed. The minimum sufficient water speed for a homemade hydroelectric power station is 1 m/s.

If the flow rate of your river or stream is below this value, then it will be increased by a small dam or narrowing pipe. But these options can cause additional difficulties. The construction of a dam requires permission from the authorities, as well as the consent of neighbors.

Do-it-yourself mini hydroelectric power station

The design of a hydroelectric power station is quite complex, so it will be possible to build only a small station on your own, which will save on electricity or provide energy to a modest household. Below are two examples of the implementation of a homemade hydroelectric power station.

How to make a mini hydroelectric power station from a bicycle

This version of the hydroelectric power station is ideal for cycling trips. It is compact and lightweight, but can provide energy to a small camp set up on the banks of a stream or river. The resulting electricity will be enough for evening lighting and charging mobile devices.

To install the station you will need:

Front wheel from a bicycle.
A bicycle generator that is used to power bicycle lights.
Homemade blades. They are cut out in advance from sheet aluminum. The width of the blades should be from two to four centimeters, and the length should be from the wheel hub to its rim. There can be any number of blades; they need to be placed at the same distance from each other.

To launch such a station, it is enough to immerse the wheel in water. The immersion depth is determined experimentally, approximately from a third to a half of the wheel.

To build a more powerful station for permanent use, more durable materials. Metal and plastic elements, which are easier to protect from exposure, are best suited aquatic environment. But they are also suitable wooden parts, if you soak them in a special solution and paint them with waterproof paint.

The station requires the following elements:

Steel cable drum (2.2 meters in diameter). The rotor-wheel is made from it. To do this, the drum is cut into pieces and welded again at a distance of 30 centimeters. Blades (18 pieces) are made from the remains of the drum. They are welded to a radius at an angle of 45 degrees. To support the entire structure, a frame is made from angles or pipes. The wheel rotates on bearings.
Installed on the wheel chain reducer(gear ratio should be four). To make it easier to bring the axes of the drive and generator together, as well as to reduce vibration, rotation is transmitted through the cardan from the old car.
Suitable for generator asynchronous motor. To it should be added another gear reducer with a coefficient of about 40. Then for three-phase generator with 3000 rpm and a total reduction ratio of 160, the number of revolutions will drop to 20 rpm.
Place all electrical items in a waterproof container.

Described starting materials easy to find at a landfill or from friends. You can pay specialists for cutting a steel drum with a grinder and for welding (or do everything yourself). As a result, a hydroelectric power station with a capacity of up to 5 kW will cost a small amount.

Generating electricity from water is not that difficult. It's harder to line up autonomous system power supply based on a homemade hydroelectric power station, maintain the station in working order and ensure the safety of people and animals around it.