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Water current

Water current scientists in the us have developed a hydro-electric generating system. The device can either convert the energy potential of a river or canal as it flows downhill, or extract energy from in and out movements of tides. The system does not require a dam for generating energy because it operates with low pressure. During the energy generation process, fishes are not harmed as the system does not require in-stream turbine. This device is being under development for the past many years.

Cablepower Energy Systems of Denver, Colorado, usa , has developed and patented this energy conversion mechanism. Now, the company is planning to even manufacture the device. The device consists of an integrated system of hydrofoil blades that are linked and held in tension by cables. This is then mounted to a platform or rafts that are either held floating in the stream flow, or rest on the sides of a diversion channel box. In effect, the blades "fly' through the water, and reciprocate by changing directions, thus changing the kinetic energy of the flow stream into high pressure hydraulic energy. Further, this pressure energy that is produced, is collected and passed through a motor to generate energy.

The aim of this energy device is to produce large-scale plants that could be sited on rivers within large urban areas. By placing the plants on already commercialised river sites, the power that is required to be brought over costly long distance transmission lines from remote dam sites can be eliminated or greatly reduced. These large plants, could then be made compatible with shipping and river uses, even in congested urban waterways.

Cablepower in early 1996, had constructed a simple, single-stage model to demonstrate the feasibility of the technology. This model was successful and exceeded exceptions. By using data verified from the model and with standard scale-up techniques, costs for a 2 megawatts ( mw ) plant were projected. Including all hard-ware components and project costs for a water-to wire scope of supply, the estimate was 6 to 12 c/k w h.

At present, Cablepower is engaged in the process of designing and manufacturing a higher efficiency prototype for demonstration in a large measurable stream. Faculty members from the Universities of Colorado and New Mexico are providing help with the research.

The site for the test has been provided by the us Bureau of Reclamation and the Northern Colorado Water Conservancy District. The test site is a 9.14 metres (m) long section of concrete lined supply canal, 3.6 m wide and 1.2 m deep. The flow of the canal can be monitored and changed within limits, to change the flow volume. Along with data collection and data feedback instrumentation, the entire device will be mounted on 2.4 x 3.65 m platform spanning the channels. The initial testing and operation of this first commercially available Cable-power system has been scheduled for June 1998.

A canal site which was seen as being particularly suitable, has been chosen for the demonstration project. The volume of flow is constant and controllable, and flow through concrete-lined beds makes siting relatively simple. Even there are several canals in the area. In the us , the us Bureau of Reclamation alone owns or operates more than 88,500 km of canals, many which require energy dissipation system to control the flow.

The great potential for using the device in micro hydro applications became apparent as the team progressed through the design process of the prototype project. In the beginning, efforts had been concentrated primarily on producing large-scale power systems for direct link-up and sale through the established grid.

However, what is needed to support many off-grid users, such as remote villages and small industrial and agricultural units, is a small compact hydropower system that produces 5 to 10 k w of continuous 12 v dc power. As the Cablepower prototype matched these requirements closely, design efforts were redirected from large plant research to a low-cost micro hydro system which could become commercially available.

The system, thus, aims to give micropower users renewable energy based at a cost that is competitive with fossil fuel systems, and without recurring fuel costs. This low head, low velocity energy extraction system offers a solution for small hydro development, avoiding the need for costly civil works and flooded land. The cost of a 1 to 5 kw system will be around us $10 to us $10,000.

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