Cappa water turbine

What is a Cappa Water Turbine? Despite being the most widely used form of renewable energy worldwide, hydroelectricity is generally reserved for large-scale commercial installations built around massive dams. Japanese company Ibasei has shrunk things down and removed the need to build a dam with its Cappa compact hydropower generator – a system that’s designed to be installed along a river or waterway. The basic design of the cappa water turbine is nothing new – blades rotate as the water flows through the unit, which drives a turbine to generate electricity. However, the unit is encased in a special diffuser that is designed to increase the velocity of the water at the point where it passes over the blades, thereby increasing the unit’s electrical output.

Cappa water turbine

Japanese company Ibasei has created the Cappa hydroelectric generator. The Cappa is essentially a shrunken dam. The device works in the same way as a dam, water pushes a turbine to create electricity, but Ibasei has designed their creation to be used on a smaller scale. Instead of using the Cappa to dam mighty rivers, the company imagines it being used along rivers and streams.

One Cappa hydroelectric generator is capable of producing 250 watts of electricity at a water flow rate of 6.5 feet per second. This power output isn’t nearly big enough to power and entire house, but and Ibasei knows that. It sees the Cappa as ideal for use in remote areas without power and during emergency situations. The Cappa hydroelectric generator is scheduled to go on sale sometime in 2013 and will sell for around the price of a compact car.

Mankind’s use of hydroelectric power has been recorded for more than a century now, and most of the time, we do tend to think of these as huge concrete structures, specially built so that entire cities will have enough juice to keep on working. Well, I guess sometimes, a paradigm shift in one’s perspective would do a whole lot of good. Case in point, the Ibasei Cappa generator that is a scaled down “hydroelectric dam” so to speak, where it offers a clean energy alternative to tiny gas and wind powered generators.Advertising

All you need to do with the Ibasei Cappa generator is to submerge it in fast-moving water, and it will get to work right away – no frills or strings attached. This is made possible thanks to a tapered diffuser housing which will increase the speed of water that flows through the turbine, helping boost the total amount of power it is capable of delivering. Having a maximum power delivery of approximately 250 watts, it is enough to power a notebook, but high powered items like a microwave is out of the question. The Ibasei Cappa generator will cost around $12,000 a pop, making it out of reach of the masses.

Pico Hydro Turbines

Principles of Turbines for high, medium and low head conditions

Pico-turbine typesEach type of turbine has its own features. The main characteristic it’s the turbines suitability for different heads and different amounts of water (see picture left). In general a Crossflow turbine has the wides application range and is very tolerant against debris in water. “Self made” Pico turbines usually are waterwheels or propeller turbines. The concept of pressurised pipes over high heads seems not to be common sense. One reason may be that channeling water towards a deep drop requires abstraction of existing landscape. It cannot be seen from a single standpoint. Informative materials may help to raise awareness for such potentials.

Experiences with Certain Pico Turbines

TP100 was developed 2008 by PT.Entec-Indonesia, to be produced in small workshops
Power500 -2000 WSite8 – 40 m @ 10 – 25 l/sCost~ 700 USDSuitable for 1 – 50 household installations
Additional cost*: 500 – 2000 USD
*depending on length of transmission cable► Factsheets on site installations in Indonesia: SalulombeandGarumpar
Infobox Tp100
TC60 (100 W)
CIT in Bandung, Indonesia developed the “TC60” inspired by Vietnamese/Chinese low cost Open Flume turbine (OF turbine) design. Sales started at the beginning of 2007. With a price less than 300 USD makes TC60 an option for private energy supply for single households. It produces 100 W at site specifications of only 3 m head and a flow < 10 l/s. Total installation cost depend on cable length from turbine to house. (50 USD/ 100 m).
Power100 WSite3m @ 8 l/sCost250 USDSuitable for 1 – 5 households (lighting)
Additional cost*: 50 – 200 USD*depending on length of transmission cable
Infobox TC60

Chances and Challenges


  • Cheapest technical solution for independent power supply.
  • Clean, sustain-/ renewable energy resource.
  • Reliable => long lifetime as it is based upon robust mechanical techniques.
  • Minimal running and follow up costs (unlike batteries at PV systems).
  • Small maintenance efforts, which are easy to follow.


  • Site specific power output => pre-feasibility check required.
  • Site specific installation => basic hydro know-how required.
  • All cost are investment cost => upfront.
  • Mostly shared connections => require community organised operation, management and use of water resources.
  • Difficult access of clients => requires hubs and/or supply structure.


Power output is limited by local conditions of height and amount of water available. Turbines are chosen by site conditions.
The following is an example for one specific turbine designed in Indonesia.

Tp100 application-range example
The colored lines indicate the power output at certain height/flow situations. The red horizontal line such turbine is technically not feasible, the blue “2 kW” line indicates a tech. maximum (for this specific turbine). The dotted lines separate three areas wherein turbines have certain sizes (30, 60 and 100 mm wide).
Example: at a site with 15 m height difference and a flow of 15 l/s the turbine can produce 1.5 kW (it will have a width of 60 mm). If on the same site (15 m) 25 l/s flow, power output will be 1.8 kW.

to produce the same electric power by photovoltaic you require about 50 m2 PV-panels (and min. 20 batteries).

Pico Hydro Materials

  • Pump as Turbine

it is possible to use water pumps “backwards” as turbines. Advantages is a wide availability also from spare parts. ► Manual how to plan a site by using a Pump as Turbine (PaT)

  • A Buyers Guide

Canadian brochure of 56 pages. Containing general information about: planning, components, costs, examples and turbine producers of hydropower installations ranging from 200 W – 15 kW. ► “A Buyers Guide” a nice overview, easy understandable.

  • Pico hydropower attempts, MHPP, Indonesia, 2007-08

A consolidation of the Pico hydropower efforts in Indonesia during 2007-08. Especially the results on a feasibility research on Family hydro units. An approach to spread turbine technology for single households or very small clusters of users.

Domestic Wind Turbines – The Basics

Households can now make use of wind power technology by installing micro turbines, also known as or small-wind or ‘microwind’ turbines. When the wind is strong enough it turns the blades of the turbine, generating electricity. The U.K. climate is ideal for wind harnessing technologies as 40% of the wind in Europe is experienced here, and in the right area you should be able to see substantial savings on your electricity bills.

Pole mounted domestic wind turbine
Pole mounted domestic wind turbine

There are two types of microwind turbine:

  • Building mounted: These systems are installed on your roof, and have a fairly small capacity, averaging 1-2kW
  • Pole mounted: These installations are freestanding and have a larger capacity of around 5kW-6kW

The Energy Saving Trust has calculated that in an ideal location a roof mounted micro-turbine system could reduce your electricity bills by around £350 a year. Your system could also be eligible to receive payments for the electricity you generate through the government’s Feed-In Tariff (FIT) scheme. Here’s how the scheme works:

  • You are paid a ‘Generation Tariff’ for each unit of electricity you generate, regardless of whether you use it or not, at a tariff rate that is fixed when you make an application for the scheme. The scheme then pays you starting from when you apply to the scheme, for 20 years. A pole mounted installation in an ideal location could receive £2,700 a year at current tariff values.
  • You are also paid an ‘Export Tariff’ for any generated electricity that you don’t use. The same pole mounted installation could receive £160 a year in export payments at current tariff values.
  • The electricity that you generate is free for you to use. If you use more electricity than your system is generating at any point you will be taking it automatically from the grid as you do now, which you will pay for. Overall, however, you will still save money on your electricity bill.
  • You can get a loan to cover the cost of installing your system by instead signing up to the Green Deal scheme. The loan is recovered via your energy bill, using the money you have saved on your energy bill by using the system. This means that the installation should not cost you any additional money.

Calculate your savings now!

How Domestic Wind Turbines Work

How a domestic wind turbine feeds electricity to your home and to the national grid
How a domestic wind turbine feeds electricity to your home and to the national grid
  • When the wind turns a wind turbine’s blades this movement drives the rotating shaft the blades are attached to. This shaft sits inside a generator. Inside the generator the shaft is surrounded by a magnetic field, so that when the shaft rotates it generates an electric current. In smaller turbines the blades can be attached directly to a generator with a magnetic field.
  • The electricity the turbine produces is DC electricity. This DC electricity passes through a device called an inverter, which connects the turbine and your home’s electrical system. It converts the DC electricity to AC electricity which can be used in your home.
  • The electricity the wind turbine generates can be fed directly into your home or stored in batteries. The turbines can be connected to the national grid so that you can export any surplus electricity and receive FIT payments for your electricity, or you can keep your turbine off the grid and store your surplus using batteries, though this arrangement won’t qualify for FIT payments.
  • If your turbine is connected to the grid, any surplus electricity is automatically exported to the grid, and if you use electricity from the grid this is also supplied to your system automatically.

The providers of the FIT scheme do not currently measure how many units of electricity you export, but for microwind turbine systems it is assumed to be 75% of the electricity you generate. The capacity of a microwind turbine system to generate electricity varies according to the individual system, and can be described in kilowatts (kW). This value can range from approximately 0 to 15. The average capacity of a house mounted system is 1-2kW and the average capacity of a pole mounted system is 5-6kW.

Whilst this measure is valuable, it does not fully describe the capacity of a turbine as the wind speeds at which this capacity is reached differ from turbine to turbine. This means that the Small Wind Turbine Performance and Safety Standard is also used. Contained within this standard is the BWEA Reference Annual Energy. This is the energy in kWh that the turbine will produce annually at a consistent wind speed of 5m/s at a set turbine height. A second value, the BWEA Reference Sound Levels give the noise level of the turbine from 25 and 60m away rounded up to the nearest decibel (dB).

Installing Microwind Turbines

When considering a microwind turbine installation it is essential that you accurately measure the wind speed of your specific location. The average annual wind speed required to make wind turbines worth the investment is a minimum of 5 metres per second (11 mph), which is not usually achieved in urban or suburban areas. This is because the wind speed in urbanised areas is usually reduced by by closely arranged buildings and trees. Nearby hills can also affect wind speed, as does whether you live in a valley or not.

Building mounted domestic wind turbine
Building mounted domestic wind turbine

It is strongly recommended that before you commission a microwind installation that you accurately measure your local wind speed by buying and fitting an anemometer (wind measuring instrument). You should leave this device to carry out measurements for at least three months but ideally you should leave it for a year to get a comprehensive overview of the wind levels your property is exposed to.

Domestic Wind Turbine Installation Checklist

There are a few important things to consider:

  • Building mounted or pole mounted: Building mounted systems have a lower capacity than pole mounted systems, meaning that they will generate less electricity and are cheaper to install
  • Whether you want to connect to the grid: Currently you will need to connect to the grid toreceive FIT payments. Contact your local DNO (District Network Operator) to arrange connecting your turbine to the grid
  • Whether your local area is prone to power cuts: When the power in an area fails all inverters connected to the grid are switched off, meaning that your system will stop working. You can install batteries with your turbine to provide a back-up electricity store – ask your installer for more information
  • Roof integrity: If you are intending to install a building mounted turbine it’s wise to consult your installer on whether your house is durable enough to support the turbine – they can be heavy and vibrate when in use
  • Planning permission: There are currently permitted development rights granted for domestic wind turbine systems in England, which should mean that you won’t need planning permission for your installation. However, the criteria for this are complex and there are varying needs for planning permission across the rest of the U.K. It is therefore wise to check the planning permissions for your installation with your local authority well in advance. You will have to supply a number of documents as well as paying an application fee of £150. It is a good idea to meet with a local planning officer before submitting your application so you know exactly what is required, as is consulting with any third parties such as neighbours who may be affected by your installation. Some installers will provide information and support with filling out planning applications
  • Environmental permissions: If your planned turbine is over 15m tall or you are planning to install two turbines you may be required to commission a bat or bird survey of the area
  • Your energy supplier: The larger energy companies have a legal obligation to be registered FIT suppliers but for smaller companies this is optional. Check with your energy supplier to see what they provide regarding FIT
  • Are you carrying out other building projects? You might be able to reduce the size of your installation bill by carrying out the work at the same time as any other building or landscaping work you are planning

Installation Time

The time your system will take to install will vary with your specific circumstances, particularly if you decide to carry out the installation at the same time as other building work.

Domestic Wind Turbine Installers

If you intend to apply to the FIT payments scheme you will need to ensure that your installation is carried out by an MCS accredited installer using parts that meet MCS standards. When your installer signs off your installation as being MCS compliant they will give you an MCS certificate that you will need when applying for the scheme. If you are financing your installation through the Green Deal you will need to instead use an authorised Green Deal installer.

Domestic Wind Turbine Costs

A standard 1kW building mounted turbine installation costs around £2000, with a 2.5kW turbine costing around £15,000 and a 6kW around £23,000 including installation costs.

Pole mounted domestic wind turbine
Pole mounted domestic wind turbine

Typically larger systems cost more to install but can generate more electricity, delivering you bigger energy savings and larger tariff payments. An average system working in a 5 m/s wind speed location can save you around £350 on your electricity bill and pay you £160 in Export Tariff payments and £2,700 in Generation Tariff payments every year. You will be paid these tariffs from the date you register for FIT payments for 20 years.!2&btvi=1&fsb=1&xpc=ZReE55zIJo&p=https%3A//

The system will run for at least 20 years, and as the tariff value is set at the start of payments and index linked it is likely that the system will pay for itself in 7 years or less. After this point you will be receiving savings on your electricity bills and payments for around 13 years. For more information on the FIT scheme you can visit our Feed-In Tariff (FIT) page.

If you cannot afford to pay for the installation yourself the Green Deal scheme provides long term finance to cover all or part of your costs. These costs are recovered through your electricity bills using the savings you have made by using the turbine. Because the payment value should not exceed your saving this should mean that the installation doesn’t cost you additional money over what you would usually spend on your electricity bill. The scheme does include 7% interest in the payments however, so you will make more of a saving overall if you can afford to pay for the installation upfront. To find out more about the Green Deal, visit our Green Deal page.

In terms of maintenance, your installer will be able to give you specific guidance on any maintenance checks that need to be carried out. Usually it is recommended that you get your system professionally checked yearly at a cost of £100-£200. The turbine system comes with a lifetime warranty but the inverter may need replacing during that time at a cost of £1,000-£2,000 for larger systems. Any batteries used with the system will usually have to be replaced every 6-10 years.Find an MCS accredited local installer

The Benefits of Domestic Wind Turbines

An average household installing a well-sited domestic wind turbine system could benefit by over £3,200 a year. This includes the money you could save on your electricity bill as well as the Generation Tariff and Export Tariff payments you could receive from the FIT scheme. Our Feed-In Tariff scheme page contains more information on this new initiative. Domestic wind turbines deliver additional benefits:

  • Reduce your carbon footprint: A 6kW pole-mounted wind turbine system can save around 5.2 tonnes of CO2 a year.
  • Pays for itself quickly: Larger systems have a payback time of around 7 years at current tariff rates, meaning that your system’s payback time could be similar or less.

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