The wind, solar, and geothermal energies have two important things in common. They are non-polluting and do no deplete precious Earth resources. However, there are differences in their cost-effectiveness and environmental imprint.

The wind is actually a form of solar energy. Air moves as the sun warms the irregular terrain of Earth unevenly. Bodies of water and vegetation contributes to the flow. When gusts move the “propeller” of a wind turbine the kinetic energy generated is converted to mechanical force. This can be turned into the electricity we all depend on.

Though wind power produces no pollution, it does have an environmental effect. The turbines are responsible for the death of birds and bats that unwittingly fly into the propeller blades. The cost effectiveness of air current energy also varies with the geographical placement of turbines. Some areas of the world are breezier than others creating more power over the course of a day.

Solar panels have become a familiar sight in many parts of the world. To use the sun’s light for power its rays are captured by different types of collectors (material that absorbs light). This can provide direct heat or is converted into another power source. One type of collector, photovoltaic cells, changes sunlight directly into electricity. Flat-plate collectors warm water by absorbing heat directly into it.

Although capturing light from the sun does not harm the environment, production of collectors and storage containers can cause pollution. It also costs more to produce electricity from the sun than from oil based fuels. That is caused by of the cost of manufacturing solar equipment and is also the result of our planet’s rotation. Light can only be harvested a half of each day. In winter climates, daylight hours are even more limited.

The core of the Earth can exceed 9,000 degrees F, hot enough to soften rock. Heat spreads from the core to Earth’s mantle (layer of underground rock) and turns the stone into semi-liquid, or magma. Geothermal reservoirs are created when magma pools. Tapping the pools provides direct-use power from steam, or is used indirectly to generate electricity. Geothermal energy is extremely clean and efficient. It is available and always ready making it a cost benefit. There is no toxic effect on the environment.

Nature provides solar, the wind, and geothermal energies free from charge but using them still costs money. Structures built to harness and use renewable sources may generate contaminants and can be costly. To choose the most suitable power, geographic location, financial concerns, and ecological imprint must be considered.

Geothermal energy can be used for hot water, heat pumps, and also to generate electricity through hot dry rock. There are, however, many variables which affect the cost of geothermal activity. While the initial price of geothermal power purchased ranges from roughly million to 0 million per MWh, there are often price escalations from year to year (one to two percent annually). This increase is entirely based on the possibility of the success of geothermal energy, on how much geothermal energy will benefit existing power companies, and how much geothermal power is going to be used.

Geothermal energy is used in over 70 countries. With the use of heat pumps it is possible to heat many homes, as well as bodies of water. The system involved includes underground pipes and loops which work with a heat exchanger and ductwork within the structure. Geothermal heat pumps can use the Earth as a coolant or a heating source. The design of the geothermal heat pump takes advantage of moderate temperatures in the shallow ground to boost efficiency and reduce operational costs. Solar heating is often combined with geothermal energy to form a geosolar system with large efficiency rates.

Geothermal hot water (hot springs) can be found underground and have a variety of uses. Water from hot springs is heated by the geothermal heat from the interior of the earth. The temperature of the earth’s rocks increases with depth (known as a geothermal gradient). If water reaches into the crust it comes in contact with these very hot rocks. The water from hot springs in non-volcanic areas is heated in this manner. Geothermal hot water can be used to heat buildings, grow greenhouse plants, for pasteurization or for fish farming.

Geothermal hot dry rock can be used to generate electricity. While geothermal energy itself is renewable, geothermal sites are not necessarily. An overworked site, or one with an excessively large energy plant, can quickly be depleted. The potential release of toxic elements also needs to be actively managed so as to minimize the impact on the surrounding environment.

When natural cracks and pores will not allow for positive flow rates of geothermal energy, high pressure cold water is pumped into the rock. This increases the rate of the geothermal energy, and the water captures the heat of the rock until it is forced out of the ground in the form of hot water. The water is then converted into electricity with either a steam turbine or a binary power plant system.