WO2012131615A1

WO2012131615A1 - Mini power plant, a system for electric power supply and a method for development of a hydroelectric power plant

Info

Publication number: WO2012131615A1
Application number: PCT/IB2012/051516
Authority: WO
Inventors: Thor MIKKELBORG
Original assignee: MINIPOWER AS
Current assignee: MINIPOWER AS
Priority date: 2011-03-29
Filing date: 2012-03-29
Publication date: 2012-10-04
Anticipated expiration: 2013-09-29
Also published as: NO332883B1; NO20111553A1

Abstract

There is disclosed a transportable mini hydropower plant for production of electric power for distribution through a non-rigid distribution network. The mini hydropower plant comprises a water turbine having a water inlet and a water outlet, the turbine being connected to a generator for production of electric power. The turbine and the generator are arranged in a container comprising a water inlet connected to the turbine water inlet, and a water outlet. The mini hydropower plant further comprises a control unit and at least one regulating device that is adapted to control the mini hydropower plant so that the produced electric power out onto the distribution network has essentially constant voltage and frequency. A mini hydropower plant system is also disclosed comprising a group of mini hydropower plants, wherein each mini hydropower plant in the group is developed for a specific combination of head and output and wherein the mini power plants in the group are developed for different combinations of head and output so that when developing a local watercourse, a ready-developed mini hydropower plant can be selected on the basis of head in the local watercourse and an electric power requirement that the mini hydropower plant is to meet.

Description

Mini power plant, a system for electric power supply and a method for development of a hydroelectric power plant

The present invention relates to a mini hydropower plant for installation at remote locations where there is no rigid supply network, an electric power supply system, a mini power plant system and a method for developing a hydropower plant.

The background for the present invention is that many areas of the world today do not have access to electricity and are at the same time located so far from existing supply networks that it is not economically feasible to build power lines so as to provide the local population with access to electric power. This is a problem in particular in developing countries where the authorities often do not have the economic resources necessary to develop the electric supply network. The alternative for the local population is then in practice in many cases a diesel generator or, more commonly, no access to electricity at all. This is a major problem for the local communities concerned and is a major obstacle to the development of the local communities.

A traditional hydroelectric power plant for production of electric power from the energy in a watercourse is realised as a project-based development, the goal of which is to achieve optimal utilisation of maximum available energy in the watercourse. In a given project, therefore, everything from the dimensioning of turbines, generators, water pipes, buildings etc. is specifically projected for this one project. This is a necessary, but costly method of developing a watercourse.

There is, in other words, a need to find solutions that can provide access to electric power to the population of remote villages in areas where there is no possibility of being connected to an existing supply network without this involving costly investments.

International Patent Application WO 99/27251 Al makes known a mobile power plant that is transported from one operational site to another. The power plant comprises a turbine and a generator that are arranged in a container and which produce electric power for operating machine tools requiring electricity, such as drills, lathes, milling machines etc., which also are arranged in the container. In other words, this is a combined workshop and power plant where the power plant produces electric power for operating the machines that are arranged in the container that is moved from construction site to construction site. The power plant that is described in WO 99/27251 Al makes no mention of supplying electric power to a non-rigid supply network with a number of consumers, or of the problems that arise when electric power with stable voltage and frequency has to be provided to a non-rigid network where large variations in the load may arise. The object of the present invention is therefore to find an economically feasible solution for providing electric power in areas where it is not economically possible to connect to an existing rigid supply network.

It is a further object of the invention to provide a solution that is easy to install, and which uses locally available power.

It is also an object of the present invention to provide a physically small power plant that can to a large extent be completed at a production site and is easy to transport to the location where the power plant is to be located.

It is also an object of the present invention to provide an alternative to generators that run on diesel or other types of fuels.

This is achieved by means of a mini power plant system as defined in claim 1, a method of developing a hydropower plant according to claim 4, a mini hydropower plant as defined in claim 9, and an electric power supply system as defined in claim 14. Additional embodiments of the invention are defined in the dependent claims. The idea behind the present invention is to harness local water power from streams and rivers for production of necessary electric power for the local community around the mini hydropower plant. When a consumer connects to a small power plant on a rigid power network, as for example in Norway, the load changes will be handled by the network, but as the mini power plant according to the present invention is to be used in places where there is no rigid network to which the mini hydropower plant can be connected, the mini power plant is also designed to be able to regulate the local non-rigid network.

By standardising as far as possible the components of the mini hydropower plant, it will be possible to obtain efficient logistics. The whole mini hydropower plant can be delivered complete from the factory and transported in a container, preferably a standard container, to the location where the mini hydropower plant is to be located. Then all that is required locally is to make a foundation for the container containing the mini power plant and lay a pipeline up along the river to the water intake. Some building work may be necessary there in order to secure the water intake, but this will not be a large structure as the river basically will not be dammed up. The mini hydropower plant will thus be a means of providing electricity to remote and poor areas which otherwise would not have had the possibility of installing electric power.

A transportable mini hydropower plant is provided for the production of electric power for distribution through a non-rigid distribution network. The mini hydropower plant comprises a water turbine having a water inlet and a water outlet, which water turbine is connected to a generator for production of electric power. The turbine and the generator are arranged in a container comprising a water inlet connected to the turbine water inlet, and a water outlet. The mini hydropower plant further comprises a control unit and at least one regulating device, which control unit and regulating device are arranged in the container. The control unit is communicationally connected to the at least one regulating device, for example, through cables or optionally through a wireless connection, and is adapted to control the at least one regulating device so that the produced electric power out on the distribution network has an essentially constant voltage and frequency.

The present invention is particularly suitable in countries where the electric supply network is poorly developed, and in places in these countries where, for economic reasons, it will not be possible to develop the supply network in the foreseeable future. Such local communities have thus in reality only one way of obtaining electric power. This is to use a diesel generator to produce electric power, which is both costly and polluting. In addition, the areas concerned are often so remote that the transportation of fuel for the generator can be problematic and often impossible when the road network collapses in the rainy season or monsoon season. In many areas in developing countries, the population therefore does not have access to electricity.

Often in such areas, however, there will be a river that can be used for the production of electric power. A local supply network can then be developed to which the local population, both private households and local trade and industry to the extent it exists, can connect. Such local development might also be a driving force for the development of local trade and industry once electric power is available.

The idea is that the mini power plant in a standard container is a complete power plant with turbine, generator and the necessary equipment and devices for being able to regulate the current in the non-rigid local supply network in accordance with the load on the supply network. Since this will be a local network of limited size, it is important to regulate voltage and/or frequency in the supply network.

In an embodiment of the at least one regulating device, it comprises an electric resistance regulator. This may be a dump load for excess electric power as for instance one or more electric resistors. This electric resistor may be a steplessly adjustable electric resistor or two or more electric resistors which are coupled in parallel.

The at least one regulating device may also comprise a water intake regulator such that the amount of water into the turbine can be varied. Such a water intake regulator is preferably provided with an adjustable valve device. The water intake regulator can, if desired, be used in combination with the electric resistance regulator. In an embodiment of the invention, the mini hydropower plant comprises a gear device that is disposed between the turbine and the generator. In addition, a flywheel is preferably mounted on the generator shaft to smooth the variations in shaft speed. The mini power plant may also be provided with a brake for regulating the speed of the generator.

The mini hydropower plant can further be provided with at least one sensor for measuring the load on the distribution network. The at least one sensor is preferably adapted to communicate with the control unit, for example, in that the at least one sensor is connected to the control unit by means of one or more suitable signal cables or, alternatively, in that the mini power plant is provided with wireless communication means. The at least one sensor may be adapted for measuring the voltage and/or the frequency and/or the electric current in the network. If necessary, a plurality of sensors may of course be used to make the requisite measurements.

On the basis of the measured value or values that are measured by the at least one sensor and transmitted to the control unit, the control unit is able to control the production of electric power so that the frequency and the voltage in the non-rigid network are basically kept constant even though the load on the non-rigid network can vary a great deal over a relatively short time.

The container is preferably provided with an opening for connection of a supply water pipe when the mini hydropower plant is installed at the installation site. If necessary, the mini power plant can also be provided with a pipe stub connecting the opening in the container to the turbine inlet. This is preferably done at the workshop where the whole mini hydropower plant in mounted inside the container.

The container also comprises an opening for discharge of water from the turbine outlet. If so desired, a pipe of an appropriate length can be connected from the containers opening such that the water is conducted to the desired location, for example, back to the river. The turbine suction pipe is preferably connected to the container opening inside the container.

During transport from production premises to the location where the mini power plant is to be installed, the openings in the container are preferably covered with suitable transport covers which can easily be removed when the container arrives at the installation site and is to be made ready for operation.

It may be advantageous to use a container that has been made in a standard size for easy transport by boat, railway, truck, aircraft or other suitable means of transport. There is also provided an electric power supply system for an area with no existing rigid supply network, which electric power supply system comprises a non-rigid supply network and a plurality of households and other consumers that are connected to the non-rigid supply network. The electric power supply system comprises a mini hydropower plant as described above for providing the electric power in the supply network and for regulating the non-rigid supply network.

For the supply of water, the electric power supply system may further comprise a water supply pipe which is adapted for intake of water from a water source and which is mounted to the container such that water can be supplied to the turbine. As already indicated above, it is initially not an objective to take out the whole potential of the river for the production of hydropower. Preferably, an amount is taken out that sufficient to meet the local need for electric power. Some of the water in the river will thus be able to flow freely. The water intake in the river may then be substantially simplified as it is not necessary to dam up the river.

The present invention also comprises a mini hydropower plant system for developing a watercourse for provision of electrical energy to a non-rigid electric distribution network in a local geographical area where there are a number of households and/or enterprises which often have a varying need for energy. The mini power plant system comprises a group of ready developed mini hydropower plants as described above. Each mini power plant in the group has been developed for a selected combination of head and output such that when developing a local watercourse, a ready-developed mini hydropower plant can be selected on the basis of the head in the local watercourse and an electric power demand that the mini hydropower plant is to meet.

By standardising alternative modules so as to be able to prefabricate them in large volumes, it will be possible to reduce the investment costs and delivery time considerably compared with conventional solutions. Technically speaking, one set of complete modules is preferably developed, the structure of which facilitates such optimal mass production in a workshop or factory.

As shown in the table below, for example, three different mini power plants may be ready developed with an output of 300kW, 400kW and 500kW, respectively. Two types of each of the three models may be developed, Type Tl for a head in the range of 25-50 metres and Type T2 for a head in the range of 50-100 metres. This means that there is a relatively wide range of models and types of the mini power plant that are ready developed, where in most cases it will be possible to find a model and a type that is suitable for the power requirement in the local distribution network and head in the watercourse that is developed. The table gives an example of the models and types that can be developed, but it is of course possible to develop more models and more types of each model, which will give a greater choice when a mini power plant is to be selected. The prerequisite condition is of course that it is possible to mount the mini power plant inside a container that can be transported from the workshop where the mini power plant is arranged and mounted in the container to the vicinity of the local installation site. The container, as mentioned, is preferably of a standard size, which simplifies the transport of the container. The container must be reinforced such that it withstands the weights and loads involved, and at the time provides the necessary stability during transport of the container to protect of the components of the mini power plant that are installed in the container.

There is also provided a method for developing a hydropower plant for provision of electrical energy to a local non-rigid electric distribution network in a geographical area with no existing rigid supply network and with a plurality of households and/or other consumers of electrical energy where, in the local area, there is a watercourse. In the method, the need for electrical energy supply to the non-rigid network is identified. A mini power plant is then selected from a group of ready-developed mini power plants such that the selected mini power plant meets the identified need for electric power in the local non-rigid distribution network, and so that the selected mini power plant is adapted to the head in the local watercourse. The mini power plants in the group of ready-developed mini power plants are, as described above, preferably developed for mounting in a standard container and with regard to different combinations of head and maximum production of electric power, for example, as indicated in the table above. The mini power plant that is selected is arranged and mounted in a container at a workshop. After the mini power plant has been ready mounted at the workshop, it is transported to the installation site, set up at the installation site and connected to the penstock and the non-rigid distribution network.

The installation site is preferably made ready for the container containing the mini power plant and penstock running from an intake in the watercourse to the installation site in parallel with the selected mini power plant being arranged and mounted in the container at a workshop. This reduces the time it takes to develop the power plant.

All the mini power plants that have been developed beforehand and which can be selected on the basis of power requirements and head are preferably configured as described above.

This way of developing a watercourse as described above gives a substantial time saving and it takes less time from the decision being made to provide the inhabitants of a place with access to electric power until the inhabitants actually have power in their homes. The fact that development is in proportion to the power requirement and that therefore a mini power plant can be chosen that is ready developed also gives a substantial saving of time, whilst it will, in the long run, be extremely economical in terms of costs as the power plant does not have to projected from scratch for each new development as is the case today, since at present power plants are developed to fully exploit the available power in the watercourse.

A non-limiting exemplary embodiment of the present invention will be described below with reference to the attached figures, wherein:

Figure 1 is a schematic view of an installed mini hydropower plant.

Figure 2 is a schematic illustration of an embodiment of the mini power plant.

In Figure 1 , an embodiment of the present invention is shown installed in an area where there is a source for hydroelectric power, for example, a river.

An electric power supply system 10 is shown which comprises a non-rigid supply network 16. This supply network is shown figuratively with masts 20 for power lines 21 which run from a mini hydropower plant 12 where the electric power is produced. A plurality of consumers 18 of electric power are connected to the supply network 16 through power lines 22 (one consumer 18 is shown in Figure 1). The consumers 18 may be households as indicated in Figure 1 , or they may be offices or enterprises etc.

The mini hydropower plant 12 is arranged in connection with a local river or a stream. A water pipeline 32 is laid from the mini hydropower plant 14 up to a point in the river where the water is taken out. Here the water pipeline 32 is connected to a water intake 30 that is arranged in the river. The mini power plant 12 is preferably designed to meet the need for electric power among the consumers who are connected to the non-rigid network 16 and will therefore often not harness all the potential water power in the river. The river will therefore normally not be dammed up completely. This makes the project cheaper and hence simpler to implement in countries where access to capital is a problem. The mini power plant 14 comprises a turbine 40 that is connected to the pipeline 32. The turbine 40 drives a generator 42 as indicated in Figure 1. A control unit 44 controls electricity production.

In Figure 2, the mini power plant 14 is shown in more detail. The pipeline 32 and the turbine 40 are connected to an opening in the container 14. The container 14 is preferably a container of standard size such that it is easy to transport from the assembly site where the whole mini power plant is mounted inside the container and optionally tested, to the location where the mini power plant is to be located and produce electric power. As mounting and testing might be carried out in Norway whilst the mini power plant might be for use in countries in Africa or Asia, it is highly advantageous to use a standard container for the mini power plant.

The turbine 40 is shown mounted in the container 14. An opening 58 in the container 14 allows the turbine 40 to be connected to the water pipeline 32.

Similarly, an opening 56 in the container will allow the turbine 40 to be connected to an outlet pipe 33.

The turbine 40 drives a generator 42. A flywheel 54 is preferably arranged on the generator shaft as shown in the figure. To ensure good quality of the power that is supplied to the non-rigid network 16, the mini hydropower plant 12 is provided with at least one regulating device 50 that regulates the frequency and/or voltage that is supplied to the non-rigid network by the generator 42 through electric lines 46. The mini power plant 12 is also provided with a control unit 44 which controls the at least one regulating device 50. The control unit 44 receives signals from one or more sensors which measure frequency and/or voltage and/or other variables in the non-rigid supply network 16. On the basis of the measured data, the at least one regulating device 50 is controlled such that the frequency and/or voltage in the non- rigid network essentially remain constant. The at least one regulating device 50 may, for example, be an electric resistance regulator or comprise a water intake regulator such that the amount of water into the turbine can be varied.

Claims

A mini hydropower plant system for developing a watercourse for provision of electrical energy to a non-rigid electric distribution network,

characteri se d in that the system comprises a group of ready- developed mini hydropower plants according to one of claims 9-13, wherein each mini hydropower plant in the group is developed for a specific combination of head and output, and wherein the mini power plants in the group are developed for different combinations of head and output so that when developing a local watercourse, a ready-developed mini hydropower plant can be chosen on the basis of head in the local watercourse and an electric power requirement that the mini hydropower plant is to meet.

A mini hydropower plant system according to claim 1 ,

characteri se d in that a plurality of private households and/or enterprises is connected to the non-rigid distribution network.

A mini hydropower plant system according to one of claims 1-2,

characteri se d in that each mini power plant is developed for mounting in a container of standard size in a workshop before the mini power plant is transported to an installation site in proximity to a watercourse.

A method for developing a hydropower plant for provision of electrical energy to a non-rigid electric distribution network in a geographical area with no existing rigid supply network where, in the local area, there is a watercourse, characteri se d in that the need for electrical energy supply to the non-rigid network is identified, and that a mini power plant is selected from a group of mini power plants such that the selected mini power plant meets the identified need for electric power in the local, non-rigid distribution network, and such that the selected mini power plant is adapted to the head in the local watercourse, and where each mini power plant in the group is developed for a selected combination of head and output, and the mini power plants in the group are developed for different combinations of head and output.

A method according to claim 4,

characteri se d in that the mini power plant that is selected is arranged and mounted in a container of standard size in a workshop.

6. A method according to one of claims 4-5,

characteri sed in that the installation site for the container containing the mini power plant and penstock running from an intake in the watercourse to the installation site is prepared in parallel with the selected mini power plant being arranged in the container at a workshop.

7. A method according to one of claims 4-6,

characteri se d in that the container with mini power plant is transported to the installation site using suitable means of transport, that the container is set up at the installation site and connected to the penstock and the non-rigid distribution network.

8. A method according to one of claims 4-7,

characteri se d in that each mini power plant in the group of mini power plants is designed according to one of claims 9-13.

9. A mini hydropower plant for production of electric power for distribution

through a non-rigid distribution network, which mini hydropower plant comprises a water turbine having a water inlet and a water outlet, which water turbine is connected to a generator for production of electric power, which turbine and which generator are arranged in a container comprising a water outlet and a water inlet connected to the turbine water inlet,

characteri se d in that the mini hydropower plant further comprises a control unit and at least one regulating device, which control unit and regulating device are arranged in the container, and where the control unit is

communicationally connected to the at least one regulating device and is adapted to control the at least one regulating device so that the electric voltage and frequency out onto the non-rigid distribution network are essentially constant.

10. A mini hydropower plant according to claim 9,

characteri se d in that the at least one regulating device comprises an electric resistance regulator.

11. A mini hydropower plant according to one of claims 9-10,

characteri sed in that the at least one regulating device comprises a water intake regulator, such that the amount of water into the turbine can be varied.

12. A mini hydropower plant according to one of claims 9-11,

characteri se d in that the mini hydropower plant comprises at least one sensor for measuring the load on the distribution network, which at least one sensor communicates with the control unit.

13. A mini hydropower plant according to one of claims 9-12,

characteri se d in that the container has a standardised size for easy transport by vessel, railway, truck, aircraft and other suitable means of transport.

14. A electric power supply system for a geographical area with no existing electric supply network, which electric power supply system comprises a non-rigid supply network and a plurality of households and/or other consumers which are connected to the non-rigid supply network,

characteri sed in that the electric power supply system comprises a mini hydropower plant according to one of claims 9-13 for harnessing water power in a watercourse in the geographical area for providing the electric power and for regulating frequency and/or voltage in the non-rigid supply network.