ENVIROMENT A small number of dams were built specifically for hydropower generation. While hydropower generators do not directly produce emissions of air pollutants, hydropower dams, reservoirs, and the operation of hydropower electric generators can affect the environment. obstruct fish migration, change natural water temperatures,river flow characteristics, 
ecology and the physical characteristics of the river.


Solar thermal energy can be used to heat water or air. It is most often used for heating water in homes and in swimming pools. It is also used to heat the insides of buildings.


A solar collector absorbs solar radiation and converts it into heat (photo-thermal conversion).The high efficiency solar collector implies maximum absorption of incident solar radiation with a minimum thermal and optical loss.

A. GREENHOUSEAll greenhouses trap solar energy during the day, usually with the benefit of south-facing placement and a sloping roof to maximize sun exposure. Stones, cement and water or water-filled barrels can all be used as simple, passive thermal mass materials (heat sinks), capturing the sun’s heat during the day and radiating it back at night.

B. SOLAR DISTILLATION: The sun provides energy to evaporate freshwater from saline water. In solar distillation, the water vapour formed from the evaporation process condenses on a clear glass or plastic covering and is collected as freshwater in a condensate trough. 
solar furnace: 1 MW and a temperature of 3300 °C. only experiment of heat and melts metal.
POWER TOWER SYSTEMSuse a large field of Sun-tracking mirrors known as heliostatsto focus sunlight onto a central receiver at the top of a tower. The receiver contains a heat-transfer fluid which is heated by the concentrated sunlight. 
PARABOLIC TROUGH SYSTEMS. They use parabola-shaped reflectors to focus sunlight onto a tube that runs along the focal-line of the reflectors. A heat-transfer fluid (oil) inside the tube is heated and used to generate steam in interchange heat to drive a conventional turbine generator which then produces electricity. 
PHOTOVOLTAIC SOLAR PLANT. They are made of silicon, a special type of melted sand.When sunlight strikes the solar cell, electrons( red color) are knocked loose.
WIND:The winds that travel around the earth have two different driving mechanisms. The first mechanism is uneven heating of the earth by the sun: equatorial latitudes receive more of the Sun’s rays than the polar latitudes. wind power is actually another form of solar power. The second mechanism is the rotation of the earth, which, through theCoriolis Effect.


There are two main designs of wind turbines that capture the wind’s energy.

The Horizontal Axis Wind Turbine (HAWT) is rather simple. Much like medieval windmills used to grind flour, modern turbines harness wind by using large angled propeller blades to catch the wind. When the wind passes through the blades, it causes the entire blade assembly, known as a rotor, to spin around a centralnacelleatop a tall tower. Inside the nacelle is housed a gearbox which converts the low-speed incoming rotational force into high-speed outgoing rotational force, powerful enough to run an electrical generator also housed in the nacelle.

It is necessary a 5 m/s of speed of wind to start. The maximum efficiency is when the speed reaches 15 m/s. But the speed is very high, it does not starTS.

The designs include theDarrieus,GiromillandSavoniusturbines.They all work on the same basic principle: the rotors spin around a central vertical tower, generating power for the gearbox and generator located at the base of the tower.

PWIND=0,37.S.V^3        The aerodinamyc efficiencyis:
                  Ewind =Pwind

1.BIOMASS:Biological material from living, or recently living organisms such as trees, grasses, and agricultural crops. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel.It is usually turned into higher heat power fuel, because it has a low energy efficiency and it takes up a lot spaces to storage.

1.1Direct Extraction

It is based in there are some vegetable species that they produces some hydrocarbons and products with a high amount of hydrogen in their metabolism . These products are known as biofuels. The process of obteining is throught crushing and adding chemical products. Ethanol and Methanol  are made from some plants, for instance palm leaves, sunflower.They are used in internal combustion engines.

1.2. Thermochemical Processes

Biomass is suffered from high temperatures and they are carried up some irrrervesible chemical processes by heat (combustion). There are some types of process.:

Biomass is burned with a big amount of air, it is obteined heat and it is used for moving a turbine and consquently electric energy is generated.

Gasification of biomass is a high temperature process in which biomass is converted into a combustible gas or syngas. Gasification takes place at high temperatures (700 – 1500ºC) and heat or amount of air/oxygen ( between 10 to 50% of theorycal amount necessary) . The air is blown to a big speed throught burning combustible.  Depend on using air or pure oxygen there are two types of products.

Pyrolysis is the thermal decomposition of biomass occurring in the absence of oxygen. It is the fundamental chemical reaction that is the precursor of both the combustion and gasification processes and occurs naturally in the first two seconds. The products of biomass pyrolysis include biochar, bio-oil and gases including methane, hydrogen, carbon monoxide, and carbon dioxide.