Geothermal Resources

Introduction to geothermal resources:

Geothermal energy is the heat from inside the earth, a kind of domestic energy which is reliable, cost effective and environmentally friendlier than other conventional sources of energy. It is released at an average heat flux of 60 mW/m2 by conduction. It is used for direct-heat use and electrical power generation.

Through production wells hot water is pumped up from the underground reservoir for generation of electricity, and then converted to steam by discharge of pressure. The steam is led into a turbine engine, which turns a generator. Remaining geothermal fluid is goes back into the reservoir to maintain its pressure.


Resources for geothermal energy


The global tectonic plates dictate the location of geothermal resources. Geo-dynamic processes like subsidence, sub-duction, uplift, fracturing result in geothermal features like volcanism and hydrothermal convection.

Common geothermal resources are:

A deep simple hot rock or magma body.

Heat carrying fluid.

Fractured or spongy rock.

Top rocks provide an insulating cover

The general geothermal resources need a fluid for heat transfer.

For direct-heat application, heat is extracted from the geothermal water at temperatures less than 120 o C which is used for greenhouse, home heating, vegetable drying and other small scale industries. The hot water spent, is used for direct application.


Technology and Resource Type


Geothermal resources  can be just liquid water, dry, a mixture of steam and water or mainly steam and varies in temperature from 30-350 o C. Water is the medium to transfer geothermal heat from the earth which is naturally occurring in most places but modern technologies extract this energy from hot dry rock resources. The temperature of the resource indicates the type of technologies required or its uses.


Conclusion to geothermal resources


Geothermal electric plants are built on the edges of tectonic plates as high temperature geothermal resources are available close to the surface

There are approximately 8,000 MW of generating and 12,000 MW of direct use geothermal resources world-wide.

Solar Wind Geothermal

Introduction to solar, wind and geothermal energy:

Renewable energy comes from natural resources like sunlight, tides, wind, rain and geothermal heat. Three major renewable energy resources are wind power, solar energy and geothermal energy. Advantage of renewable energy is that they are inexhaustible, environmentally friendly with low dangerous pollutant emissions.



Solar energy


Solar energy is derived from the sun in the form of solar radiation. Electrical generation by solar power relies on heat engines and photovoltaic. Solar applications include day lighting, solar architecture, solar cooking, solar hot water and for industrial purposes.

Solar technologies can be classified as passive or active, depending on the method of intake, conversion and distribution of solar energy. Active solar techniques include solar thermal collectors and photovoltaic panels to harness the energy. Passive solar techniques include selecting materials, orienting to the Sun, light dispersing properties, and designing spaces that naturally circulate air.


Advantages and disadvantages of wind energy


Flow of air is used to run wind turbines which provide a source of clean and renewable energy for homes or business. Small wind energy devices generate power very cost effectively.

Wind turbines range from 600 kW to 5 MW of power. The power output is the cube of the wind speed, hence power output increases as the wind speed increases. Offshore and high altitude areas where winds are stronger are preferred for wind farms.

Advantages:

Wind energy is friendly to the surrounding environment,

Wind turbines take up less space than a power station.

The wind is free.

Wind turbines can generate energy in remote locations.

Disadvantages:

The winds unreliability factor, which can be too low to support a wind turbine or wind farm,

Wind turbines produce less electricity than fossil- fueled power station; hence multiple wind turbines are needed to make an impact.

Construction can be very expensive.

The noise pollution from commercial wind turbines is sometimes similar to a small jet engine.


Geothermal power energy


The earth contains a large amount of energy in the form of heat. Geothermal energy is obtained by using the earth's heat from kilometers deep into the Earth's crust or from some meters. All this geothermal energy has the potential to generate power to provide electricity.

Three different types of geothermal energy power plants are used to generate power: flash, dry steam and binary.

The best advantage of geothermal energy is that they are useful even in cold regions like Norway and Sweden by using ground source heat pumps.