It’s a form of energy, a renewable resource. Other renewable resources include geothermal, ware power, wind

power and solar power. Hydroelectric power plants do not use up resources to create electricity nor do they pollute the

air, land or water. Hydroelectric power comes from flowing water, winter and spring runoff from mountain streams and clear lakes. Water , when it is falling by the force of gravity, can be used to turn turbines and generators that

produce electricity.

The mechanical power of falling water is an age-old tool. As early as the 1700’s the advantages of

mechanical hydropower were recognized and were used for milling and pumping. Hydroelectric power became

more and more important to our world. Growing populations and modern technologies require vast

amounts of electricity for creating, building and expanding. The efficiency of today’s hydroelectric plant is about 90%.

From the antiquity still the person exploited the force of water that is found in movement, using primitive wheels. The

hydroelectric energy with her current form was unknown as the season where was discovered the electric engine for the

production of electric energy. Today, the hydroelectric energy constitutes most important part of energy that is consumed by

the humanity. Her advantages are important. It does not present no problem of pollution of atmosphere or marine water

and her cost, afterwards the damping of hydroelectric work, it is almost nothing.

In a lot of countries that have favourable morphology of territory, the production of this type of energy often exceeds the

80% of total production of energy. For the production of hydroelectric energy we exploited the difference of altitude that

exists between the reservoirs of water and in the machines. The water, through suitable dam, is assembled in artificial lake. The locality where is manufactured the dam, should be such, in

order that the water is used not only for the production of energy but also for the irrigation of regions that are close to the

dam.

Hydroelectric Power’s environmental and future role in Greece

Advantages:

Hydroelectric power plants do not use up limited non renewable resources to make electricity.

They do not cause pollution of air, land or water.

They have low failure rates, low operating costs and are reliable.

As an added benefit, reservoirs have scenic and recreation value for campers, fishermen and water sports enthusiasts. The water is a home for fish and wildlife as well. Dams add to domestic water supplies, control water quality and avert flooding.

Hydropower does not discharge pollutants into the environment, however, it is not free from adverse environmental effects such as providing safe fish passage, change of groundwater level, fill up of the river bed with rubble, risk of dam breaks and great demand for land space for the reservoir. Efforts to ensure the safety of dams and the use of newly available computer technologies to optimize operations have provided additional opportunities to improve the environment. Hydropower research and development today is being conducted in the following areas

Fish passage, behavior and response

Water quality

Dum safety

Operations and maintenance

Water resources management

Today, engineers want to make the most of new and existing facilities to increase production and efficiency.

Sfikia DamIn the river Aliakmona one of the richer aquatic resources of Western Macedonia with a

lot of tributaries finds one from the bigger hydroelectric dams that of Sfikia.

The factory of peak of Sfikia functions from 1985, has installed force of 3 units of 105 MW and he is unique in Greece today that his units are reversible.

It has been manufactured above the river Aliakmona. It is a natural watercourse that was separated artificially with the dam with hypsometric difference 92 m. The dam includes a swirl height 73m with pressure roughly 6,5pascal. The scale of water is altered reaching 65 m (biggest price). Under the surface of Aliakmona exist 3 big units each one from which have weight of 700tns something which renders their work difficult if in deed we think that it functions without brakes. In their upper part a generator exists and in the same part an engine is found that realises 150 turns thin. Because there are no brakes this engine executes reverse move.

Moreover an inverter of phases is used that can turn the engine right and left.

In order to pull again behind the water is used a system of air and the water is being emptied by a turbine.

Afterwards tendency is given in one of the turbines so it crowns the system that touches 120-150 rotations . This way the pressure is decreased and water goes up again . This re-use of water has important economic profits.

A control and security room also exists in this space as well as enough metal cabs that contain all the essential information for the proper function of the dam, which give all the commands in order to begin the process for the production of electric current changing in digital signals the various data. Still on these cabs they are incorporated certain tables that give the signal for the event of a breakdown. Below the surface of Aliakmona exist three types of pipes . The blue pipes contain and transport water. The red ones are for firefighting and yellow lubricants . More pipes exist beyond a yellow machine. In this machine a system exists that transforms mechanic force into electric. The axis of slipping is common. There are doors that prompt, direct and spin the water. In the next room there are instruments that remove charges from the engine, keep the tendency constant and variate the turns . In the end there are three drivers with diameter seven hundredth each one. In these drivers there are doors in order to keep the tendency constant for example they open a lot when there is limited quantity of water, while on the contrary they open little when the level of river goes up.

GlossaryDam: A massive wall built across a valley or a river for

storing water.

Generator: A machine that converts mechanical energy into electrical energy.

Hydroelectric Power: Electric current produced from water power.

Hydroelectric Power plant: A building in which turbines are operated, to drive generators by the energy of natural or artificial waterfalls.

Turbine: A machine for generating rotary mechanical power from the energy of a stream of fluid such as water, steam or hot gas.