There are currently three types of plants: Dry steam plant, Flash power plant and a Binary power plant. Dry steam plant operates the dry steam reservoirs, which produce very little water. The electricity is produced by directly piping the steam to push the turbines of the power plant. F;ash power plant is used to collect energy from natural reservoirs, where the temperature range is much lower 300-700 degrees F. The water is brought to the surface from the deep reservoir through the production well, while being released from the pressure, so some water is flashes into steam and transferred into a separator, which then spins the turbine and generates the electricity. The third type of plant, the binary plant can be used in even lower temperatures, as it is able to collect energy from a source where the temperatures range from 250 to 360 degrees F. This plant uses a heat exchanger and a liquid, that has a lower boiling temperature than water, e.g. opentane, which then vaporizes and forces the turbines to spin generating electricity. The vapor, like water is then re-condensed and returned into a heat exchanger, like the water returns to the natural reservoir. No waste is produced, because it is, as well as in the other systems above, a closed cycle with no emissions into the air.

That is why type of energy production is considered one of the cleanest.

The three types of plants we talked about above use underground water and steam from natural reservoirs and while they are only present in places with specific geological environment, underground hot dry rock is available everywhere. A new way of harnessing geothermal energy is currently being improved. The new type of power plant uses hot rocks buried very deep under the ground to heat up water via heat exchangers and piping, the cycle is basically the same, but more complex due to the more complicated heat transfer. With improving drilling technology geothermal energy from hot dry rock could be available virtually anywhere and in the near future we will be able to find out the true capacity of earth’s heat resources without harming the environment.

Although geothermal power plants are not common everywhere in the world due to their costs, they are used in most of the developed countries. The biggest producers and utilizes of geothermal energy are United States, New Zealand, Italy, Iceland, Mexico, the Philippines, Indonesia and Japan.

Here we will try to introduce you to the renewable energy sources (RES) available today. RES refers to energy resources which are naturally replenished: wind, solar, hydro-power, biomass, geothermal energy, ocean energy.

The EUROSTAT’s definition of RES: Renewable energies cover hydro-power, wind energy, solar energy, biomass and wastes and geothermal energy. Renewable energies are the sum of hydro-power, wind energy, solar energy, biomass & wastes and geothermal energy.

Today, renewable energy is mainly produced and used domestically. Traditional biomass (for cooking and heating) is growing just slowly as it is used more efficiently or replaced by more modern energy sources, large hydro-power is growing slowly, new renewables (small hydro, modern biomass, wind, solar, geothermal and bio-fuel) are growing very rapidly.

Modern applications of renewable energy have grown steadily over the past three decades and the investment to developing renewable energy capacities in countries is growing rapidly, from $6 billion in 1995 to over $50 billion in 2008

The good news is that renewable resource potentials exceed today’s world energy consumption.

Renewable energy policies and promotions, as well as new targets already exist in more than 50 countries all over the world. Most of them are targeting the share of renewable energy in the electricity generation (typically 5 – 30 per cent). This is true for most developed countries. And as far as we can tell the most rapid changes can be seen in South-Eastern Asia and China.

The biggest problem in developing new RES policies and projects is the lack of a unified system, that would provide information on the know-how and statistics periodically and transparently. The are also copyright law issues and very significant differences in the definitions of RES stated by various organizations. The other interesting fact is that no matter how rapidly the investments to the sector increase, there is still not nearly enough funds to reach the average term goals for this type of resources.