We must find and use renewable sources of energy to meet future demands.
Large scale hydro power plant could have been a better solution, but this technology has got its negative environmental aspects. Large scale hydro power plant needs a dam and reservoir. A dam to create a reservoir may obstruct the migration of fish and other marine life. A reservoir and a dam also can change the flow characteristic, temperature, marine life diversity, chemistry and silt load amounts. These environmental effects can significantly change the ecology of the river upstream and downstream. These changes may have negative impact on the deltas that form where rivers merge to the ocean. Also reservoirs can cover vast area, agricultural lands, sites and more over it can cause relocation of people living there. Also a quite large amount of greenhouse gasses may also form in reservoirs, depending on the temperature and lo-cation.
On the contrary water current turbines can be used without a dam to generate electricity for home scale remote power systems.
These so-called micro-hydro installations can be a very good complement to a solar power system, as they pro-duce electricity 24 hours a day. A micro hydropower plant has a capacity of up to 100 kilowatts. A small or micro hydroelectric power system can produce enough electricity for a home, farm, ranch, or village. Small water turbine will produce power non-stop, as long as running water is available, no matter what the other conditions may be.
Micro water current turbines are most suited for places where there is an almost a constant flow of water, throughout the year. The under developed and developing countries can use this techniques to provide electricity to remote places where transmission line cannot be connected easily or the cost becomes very high. And the countries like Bangladesh where there are hundreds of rivers and all of them have got constant flow of water throughout the year, this scheme can be a real solution for power scarcity problems.