Alternative Energy              

by Marco Scalon

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Definition

Alternative energy is the term we use to refer to the energy created by the use of sources different from fossil fuel; these resources are renewable and have a low impact on the environment.

Alternative Energy Sources

Alternative sources to fossil fuel are biomass, wind, sun, water and geothermal.

 

 

Interesting......

Geothermal energy covers 19.1% of icelandic energy, and it's used by 87% of the homes in the heat system!!

 

 

 

 

 

 

 

pic: Krafla Geothermal Station in northeast Iceland

and talking about Iceland...........

 

 

 

 

 

World Sunlight Map

pics: Solar troughs are the most widely deployed and cost-effective solar thermal technology     

Helios UAV in solar powered flight

 

 

 

 

 

 

 

 

 

pics: Hydroelectric dam in cross section

Rance tidal power plant, France

 

 

 

 

 

 

 

 

 

 

 

 

 

 

pic: the most common modern design of wind turbine: the 3 blades model minimizes forces related to fatigue

 

Biomass

When we talk about biomass we have to understand that, yes, we can burn biomass by itself (in fact, biomass is a "just-dead" material, usually plants....we burn biomass when we burn wood in a stove! ), but when we talk about it as an energy source we actually talk about its products, methane gas and alcohol, which can be use as fuels in the combustion.

Even if in this way seems like burning normal fossil fuels, is not the same; biomass is material whose carbon is in the atmospheric cicle, and will return in it even if we don't burn it, so it doesn't break any equilibrium. When we burn fossil fuels, instead, we put in the atmosphere carbon that has been taken out the cicle a long time ago, and won't return in it if not for our use.

 Geothermal

The source of this energy is the heat stored below the earth surface; since the principle of every power plant is to produce steam and, from it, make a turbine turn, why don't use it when is naturally formed?   In a geothermic power plant, the steam is taken from below the surface, and the water formed is then re-injected in order to produce more steam. In this way the impact of the environment is almost zero, the source is endless and power plants can be built on a degree of scalability: a big plant to "feed" a big city or a small one to give electricity to small villages.

Its price is really competitive and works day and night, uneffected by the weather; the real problem is that it is available only in certain areas, and it's not well developed even there: it produces only 1% of the energy in the world.

The Nesjavellir Geothermal Power Plant in Iceland

 Solar Energy

Using the power of the sun means convert sunlight into electricity by photovoltaics.

The energy of the sun is also used in solar water heaters, cookers, devices for distillation and disinfection and, right now still prototypes, vehicles for ground, air and sea transportation.

 

Solar troughs are the most widely deployed and cost-effective solar thermal technology.Helios UAV in solar powered flight

Energy from Water

Water gives us energy in different ways. First and more used is from dams, 19% of world energy, well developed in China, Russia, North America, South America and North Europe.

Another important form of energy is the tidal power, not yet used a lot, but seen, for its predictabiity and "strenght", as an important energy source in the future.

Last, we have wave power generation, a fairly new and not yet widely developed way of producing electricity from waves; as for now, no big wave farm has been built yet.

Hydroelectric dam in cross sectionRance tidal power plant

Wind

Wind power is the conversion of the wind's energy in a useful form, electricity. It uses the same principles of the "old windmill", with a turbine which is rotated by the wind; from the movement, we "create" electricity.

Even if in this way is produced about 1% of the world-wide energy use, it's really important in Denmark ( 19% ), Spain and Portugal (9% ) and Germany and Eire ( 6% ).

This 3 bladed wind turbine is the most common modern design because it minimizes forces related to fatigue.